For reference, this city is about as north as Anchorage Alaska and today they got less than 7 hours of sunlight and it'll continue to decrease for the next 3 weeks.
The Nordic countries generally still wants to increase their wind and solar power, but the big issue during winters is when there's cold air high pressure systems we get neither sun nor wind, having an energy storage that can hold up to 5 days worth of energy should help us nudge past them.
Hydro-energy exist (mainly Sweden and Norway, but I think some in Finland as well), but it's fairly built out so stable non-fossil power needs to be nuclear, or wind/sun + storage (that hasn't been good enough so far).
One of the interesting things about hydro is that it's usually constructed to satisfy baseload power. In reality, shifting that over to a peaking plant requires relatively modest changes to system, a small fraction of the cost of an entirely new dam. You don't actually need the "Pumped" part of pumped hydro, you can just throttle normal hydro on and off if you have enough turbines (though for ecological & geomorphological reasons some minor downstream damming also helps). There wasn't any reason to install the extra turbines in the age of fossil fuels. They only take ~30 seconds to spin up, versus days or weeks for thermal plants.
> You don't actually need the "Pumped" part of pumped hydro, you can just throttle normal hydro on and off if you have enough turbines (though for ecological & geomorphological reasons some minor downstream damming also helps).
Yeah that generally can work for a week or so, not for entire season.
Imagine if we build hydro to full capacity and monetize the excess with data/compute centers and/or crypto mining. We'd have so much spare capacity for any residential or industrial purposes.
Datacenters and crypto are evidently a bad source for large-scale load variability because their significant capex demands that they be kept running 24/7.
This is often a problem with variable load schemes that do any useful work, rather than just dumping heat into something. It would be interesting to see a list sorted by just how thick they are with capital considerations. Aluminum smelting, hydrogen electrolysis, lots of other options on that list.
> their significant capex demands that they be kept running 24/7.
US companies are sitting on a pile of not yet connected GPUs because they have no place to put them. They would take 10 out of 24h if they could get 10. It's better than zero that they currently have for those GPUs.
Same with crypto. No point of running a rig if it's losing you money becaus electricity is too expensive at this moment. Regardless of capex sometimes it's better not to run it.
> “Hydro-energy exist, but it's fairly built out so stable non-fossil power needs to be nuclear, or wind/sun + storage”
Interconnectors also exist (and more are planned), which means, for example, that Norway can buy wind energy from the UK when it’s cheap and abundant, in preference to using stored energy from their hydro lakes.
That way they effectively get more out of existing hydro lakes, which in Norway is already a very significant storage capacity.
Theres not going to be built any more interconnectors from Norway anytime soon.
Electricity became a lot more expensive in Norway after building several interconnectors to UK and mainland Europe. Importing high prices from the failed energy politics of UK and Germany which both have among the most expensive electricity in the world.
This has been a huge debate, and the general concensus seems to be that joining ACER and building inrerconnectors to mainland Europe was a big mistake.
About 90% of Norway's 40 GW energy production (mostly hydro) is state owned. By exporting energy and thereby getting other countries to pay, the money literally goes to the norwegian people. Not directly into their bank accounts, but into their govt budgets, which they later pay less in taxes.
Norwegian power generation is sized for the domestic market, so tax income from selling excess is marginal at best. The power bills however have indeed crept quite a way up. This was especially noticeable in the first winter of the Russian invasion, when the Nordics had to subsidize the bill that suddenly dropped on short-sighted German energy policy.
Germany benefits a lot from the open market. If only countries introduced a rule to export only the excess of the energy then Germany would be cooked, because prices would sky rocket for them, not 2x, 3x, but way more. Luckily for them they can make strategical mistakes and go away with it making others to pay for that.
Example, the Netherlands had the biggest gas reserve in forever. It's 2/3rds or 3/4ths empty now and extraction has or is stopping due to it causing earthquakes. But the income from exporting the excess gas has been used for socialist policies. Now that that income is gone, and now that expenses for gas have gone way up (also due to reliance on cheap Russian gas), people are feeling it in their bank accounts directly and the socialist policies are being dismantled one by one.
Do they actually pay less in taxes because of this? I’m not arguing. That is great and I would appreciate if you could provide a source for me to read.
We do not but there's a social consensus about the value people get from this taxation level. However the excess power price which is not a domestic supply/demand outcome is a lot harder to sell.
There are government subsidies for consumers to either have a fixed price or a price cap on electricity in Norway as a political response to the increase. This would be harder to pull off if not most of the profits from export didn’t land in the public sector (either taxes or government owned energy companies).
> Importing high prices from the failed energy politics of UK
Remember that its a market, not the consumer price.
The spot price for UK electricity is still quite competitive in the winter, just not reliable.
The other thing to note is that peak in the UK is different to peak further up in longitude, which means that there is benefit to both countries for this.
Electricity prices don't go up because you have access to expensive power, it goes up because you don't have enough cheap power so you have to buy the expensive power.
It seems like Norway just wouldn't have power if they weren't connected to other sources, not that they'd have more cheap power.
Electricity prices go up when you have access to customers who are willing to pay more. If grid connections to other regions are limited, people in regions with a lot of cheap generation (such as Norway) pay low prices. But if you add grid connections without increasing generation capacity, prices start equalizing between regions, as every power company tries to sell to the highest bidder.
Norway could power itself fully with domestic hydro. But it chose not to, as the power companies make more money by importing foreign power when it's cheap and exporting hydro when it's not.
Washington state has the same problem to a lesser degree. California pays more for cheap Washington hydro, which causes the costs to go up for us, although I guess not as drastic as Norway since our electricity is still considered cheap.
> "Norway could power itself fully with domestic hydro."
We have events where the we cannot get enough load from domestic production. Typically in winter when water freezes.
> It seems like Norway just wouldn't have power if they weren't connected to other sources, not that they'd have more cheap power.
This is not the case as Norway and neighbouring Sweden have plentiful hydro. It's especially valuable as it can be regulated to complement wind/solar fluctuations, essentially replacing storage.
Obviously the presumably large amount of money spent to interconnect could have been spent adding local production and storage. It would be a waste of money if there was a reasonable path to local energy independence that was neglected.
A significant proportion of Norway's domestic energy production is hydro, which comes with it's own "built in" storage up to the capacity of the dams, so Norway already has a very significant storage capacity.
Estimates suggests a storage capacity of 87TWh of storage in hydro reservoirs, compared to production capacity in recent years between 146 and 157 TWh, and a theoretical production capacity of ~309TWh (I don't know the basis for that - I'd imagine peak production at all the plants, but I doubt that could ever happen in reality, so the 146-157TWh based on real production are better...)
Compare that to Norwegian electricity consumption of 124 TWh in 2020.
Of course, since so much of Norways total electricity production is hydro, large storage is necessary, as the hydro supply is highly seasonal, based on e.g. things like the amount of melting snow in the mountains in spring.
they have too much cheap power, so they decided to sell it. But the fact they have a buyer that buys for more than locals, means they do not longer have to sell to locals at low price.
Tho it being state owned make it weird, you'd think state would keep lower rates for the people
Prices went up in norway because the uk had even higher prices than norway.
Having these interconnections is good for producers in norway and consumers in Uk, but very bad for consumers in Norway
It’s basic supply and demand. And by linking to other grids, you increase demand since there’s now more customers for your supply. What they have (comparatively) less is supply since the supply in those markets is shite in comparison to what Sweden and Norway have for their local demand.
Even Southern England cannot get enough wind energy from Scotland to fully utilise wind farms because transmission capacity is insufficient. I would imagine a transmission line to Norway will be even more expensive than to England.
But they are building such a link, because it'll make/save more money than it costs.
Imagine how many doom and gloom headlines we'd have avoided if these two massive construction projects could have been sync'd up perfectly or if we had a national press that could do anything other than try to scare people with big numbers.
I think the point is that winter can create periods where there is neither adequate wind or adequate sun. Having strong wind production at some times will only be good if there's a way to store the excess. That's exactly what this project does and I believe that was GPs point.
Hydro energy generation is fairly built out, but the Nordics have lots of places suitable to build out hydro energy storage. Hydro generation requires a flow to dam, but storage doesn't.
We don't really. Hydro storage requires reservoirs where you can freely adjust the water level. Most of our lakes have shorelines that have been built out, and the property owners get really angry if you suggest frequently adjusting the water level significantly.
The largest planned hydro storage projects are using decommissioned mines, and those are going to run out quickly.
You could just build a back-channel for the existing hydro-dams? Those reservoirs are only full for a short period and that is when you dont need pump energy.
But where? In Finland, at least, the land is relatively flat when compared with Norway and Sweden, and with a large rural population there aren't really any good locations.
In my local area, we had major flooding this spring because the hydro plant operators were sleeping on the job (or whatever they did instead of regulating water levels). And that was a simple 2m increase in water levels.
NO/SE have some more geographically suitable locations, but last time I checked, flooding them was considered too environmentally destructive too the local environment.
Yeah, you're right regarding the environmental concerns.
Most of Norway's hydro dams were built a long time ago when there was little focus on the environmental effects.
The last major plant went live in 1993. Most of the focus now is on far smaller schemes, that doesn't really add up to a lot compared to Norway's established generating capacity (which outstrip the total electricity use anyway), but which also meet far less opposition.
Part of the reason for that was growing local opposition to larger plants, and sometimes national opposition, culminating with the Alta controversy[1] in the late 70's that were some of the largest civil protests in Norway since the end of WW2. The protests eventually failed, but it had a lasting effect on Norwegian politics.
If you pump the water back into the existing reserviors you will have less flooding?
I suggested a pump-water extension to existing hydro power reservoirs.
Like your EV recharges when you release the pedal.
Right shouldn't talk about EVs with a Finn, that analogy will not fly. Ok, like if you plan carefully where you throw up your koskenkorva you can re-use it.
The reservoirs in Finland aren't quite at the scale your Explorer Vodka-fuelled Swedish mind believe them to be. Most are small generators hooked up to the local rivers, and are required to prioritize keeping the water from flooding residential areas.
There's a reason we're looking at using old mines for pumped hydro rather than trying to pump water upriver during a spring flood because other power sources have surplus generation.
You could use the ocean for the bottom level and an artificial reservoir for the top level. You're not going to noticeably affect ocean levels.
Or just use a large lake. You're not going to noticeably affect the water levels of a large lake. You might pump 10 billion litres of water, which is .02% of the volume of Mjøsa.
10 billion liters of water is 1,000 m^2 * 10m deep. There is no suitable location for that that is both elevated enough and near enough to Mjøsa to be financially viable.
Norway also existing hydro reservoirs with a capacity equivalent to around 6-8 months electricity supply, so it's not really a major need for Norway, anyway, but this is a fairly general problem: Finding suitable locations that are close enough to a water source, and provides a large enough potential reservoir is hard.
Looking at a few of them, a few obvious problems are apparent.
Firstly, it takes a rather liberal idea of how close the basins need to be to each other to be viable.
Secondly, most of the ones I looked at would require extensive relocation of existing populations and/or large-scale infrastructure changes, such as re-routing important roads.
The first few I looked at also do not have a sufficient water supply nearby - you'd face either covering them or you'd quickly run into problems of evaporation that you have little ability to replenish/replace.
A lot of the ones I quickly looked at would also face "fun" issues such as no nearby infrastructure such as roads to bring in construction materials.
I have no idea how many suitable locations there are on that map, but it seems pretty apparent it is a small fraction of the ones marked before you even consider how many would be politically unviable because of public resistance to the environmental destruction.
To be clear, I'm not at all opposed to investigating pumped storage, but it's also not nearly that simple.
> And pumped storage is significantly cheaper for seasonal storage than any proposed alternatives.
This is incorrect. There is currently not a single pumped hydro station that is suitable for seasonal storage. They're all designed to drain their upper reservoir in 4-16 hours.
It's the only thing that's half economical. Do the math: Even a modest power plant - 1 GW output - that can run for 1000 hours means you need a 1 TWh (even typing it feels ridiculous) storage reservoir. If you only have 100m of head, that's 3 cubic kilometers of water. That would mean building an artificial lake that immediately would be Norway's 6th largest body of fresh water, and draining it completely every winter.
And effectively, you'd have to build it twice - you also need a lower reservoir. Because there's nowhere to get 3 cubic kilometers of fresh water to fill it otherwise, and you really don't want to do pumped hydro with seawater.
Norway already have seasonal storage with a storage capacity equivalent to 6-8 months of total electricity use in the form of its existing hydroelectric plants, with no need to pump things back up again.
> And yet it's still far cheaper than any other form of seasonal storage.
Only for countries with very suitable landscape, and the willingness to use it - damming high altitude valley is extremely unpopular and bad for the environment.
Also, pumped hydro is expensive. Initial capex is higher than today's lithium batteries, if you design comparable systems. The only reason anybody is still building new pumped storage is that you can use it for 100 years (instead of 20 for the batteries, although nobody really knows how much they'll actually degrade).
I think we'll find hundreds of TWh of seasonal storage elsewhere. Thermal storage is extremely attractive if (or once) you have district heating installed. Takes care of a massive junk of domestic heating, and could take over light (food processing, paper,... ) and medium (chemical, ...) industry. Just don't try to turn it back into electricity...
Once steel and concrete get electrified, we might get seasonal hydrogen storage in underground salt caverns. Concrete and steel need absurd amounts of high heat which probably means making lots of hydrogen, putting those in the right locations might make additional hydrogen for fuel cells/gas turbines available, relatively cheaply (still extremely expensive, seasonal storage always is). But who knows...
> A typical pumped storage facility uses 100m of delta
Most projects seek 200-600m. This map doesn't even consider pumped hydro <200m: https://maps.nrel.gov/psh
> And pumped storage is significantly cheaper for seasonal storage than any proposed alternatives.
Based on what? Cost is particularly variable for pumped hydro. It can be one of the cheaper options when stars align. But you need 1) a suitable geography that minimizes the cost of damming or digging a resivoir with sufficient head 2) available for development without too much backlash 3) Near enough grid resources to minimize infrastructure and line losses. I'm surely leaving pieces out.
It can be cheap, but it has far more hoops to jump than alternatives like batteries, hot sand and other "storage-in-a-building" designs which can be built where needed and using fairly standard industrial construction.
True, but that disrupts ecosystems. Or so the argument against go building storage dams go.
That said, there's been a fair bit of talk here in Norway recently about tax incentives blocking hydro owners from upgrading old generators, improving efficency. Apparently a lot of currently unused power available if they "just" did that.
I wonder if it's possible to also increase the amount of generation on existing dams? I could imagine there being situations where there's excess peak flow capacity but it isn't utilized because the flow rate would be unsustainable. But if we're looking for storage it could make sense.
A reversable pump-turbine is not significantly different from a standard hydro generation turbine, and there are tons of examples of those operating in cold regions.
> Are there extant succesful examples of pumped hydro in cold regions?
There's some pumped hydro at Niagara falls in Canada, which is far enough North that it should see a bit of a that/freeze cycle but is still a relatively mild climate.
Don't know anything about what issues this does/doesn't present to them, just happen to know it exists.
For reference, Niagara Falls is at roughly the same latitude as Barcelona and Milan. Vääksy, Finland, is approximately 1,250 miles (2k km) north of there, slightly north of Anchorage, Alaska.
Latitude is a poor point of comparison here, North America tends to be substantially colder than Europe at the same latitude.
Or concretely Niagara Falls goes from an average low of -6.44 C in February to 21.0 C in July. Barcelona an average low of 4 C in January to 20.2 C in August (according to the internet).
But yes, it's warmer than Finland, just cold enough to see something of a freeze that cycle.
A couple days of -6 is probably a lot easier. Its probably still economical enough to heat the equipment on the days below 0. I imagine having a couple months of -20 is a bit different.
Either fusion or drill baby drill is necessary. Watt’s steam engine was absolutely horrible, but it was the worst steam engine ever built. If Finland builds the worst deep geothermal ever that still works, we can hope for better ones.
Yeah I know drilling through ~8-10 kilometers of rock is kinda hard… they know, they tried, maybe it now is a good political climate to try again?
> Yeah I know drilling through ~8-10 kilometers of rock is kinda hard… they know, they tried, maybe it now is a good political climate to try again?
The Finnish 7 kilometer geothermal drilling failed commercially, I guess that's what you're referring to. Is there any reason to assume drilling deeper would work?
Yeah, that’s the one. Economics of this are hard - but money is numbers in computers, it’s just a question of how serious the government is with getting it done - physics-wise it gets like 10-15C warmer with every km, which is important for the delta T obviously. I know nothing about drilling the extra couple km, though, only assuming it can be done with enough engineering.
I understood that temperature wasn't the problem. How it works is that you pump water into one well, and get it out from an adjacent one. The main problem was permeability, they couldn't get the necessary flow rate between the wells.
They tried in southern Finland not long ago. At great expense and spending a lot of time they managed to drill down 6-7 km until they figured out that the porosity of the rock down there was so poor that it was impossible to make the project economical, so it was cancelled. The idea was to pump this heat directly into the district heating grid.
> but it's fairly built out so stable non-fossil power needs to be nuclear,
Or just gas turbines running on decarbonized fuels. The backup for the "10 year winter" can be fossil fuels. It is such a minuscule problem that it does not matter in the slightest.
It is essentially the emergency reserve we are talking about, no point wasting tens of billions in subsidies per new built nuclear reactor.
Those "10 year" winters seems to appear every year with producers falling back to burning fossil fuels to keep the grid working.
Now part of that problem is that we more or less constantly export electricity to Germany (but that was because they closed their nuclear plants).
The main problem domestically in Sweden is that 30% of current electricity generation in Sweden is nuclear, but the _newest_ plants are 40 years old, on top of that the electricity generation needs to increase, steel mills de-carbonizing, more electric cars and so on.
For a few hours leading to insignificant emissions.
> Now part of that problem is that we more or less constantly export electricity to Germany (but that was because they closed their nuclear plants).
We have previously imported way more. The problem nowadays is that carbon emissions are expensive and even more so when coming from LNG rather than pipeline from Russia.
In other words: our prices were previously more aligned with Germanys because ours were more expensive and Germanys was cheaper.
If you are Swedish, or understand Swedish following from the "we", take a look at this talk starting at 43:40 to understand where the prices are coming from:
> The main problem domestically in Sweden is that 30% of current electricity generation in Sweden is nuclear, but the _newest_ plants are 40 years old, on top of that the electricity generation needs to increase, steel mills de-carbonizing, more electric cars and so on.
And new built nuclear power won't be online until the 2040s. Are you saying that we should wait until the 2040s to decarbonize those parts of the economy rather than do it ASAP with renewables and storage?
The existing nuclear power fleet has now targetted their maintenance on operation until the 2060s, so it is not like it will disappear overnight.
I'm not ruling out Nuclear in general, but let's remember that:
* Energy can also be carried northward from other areas in the same country or neighboring countries, where there are more sunlight hours or more wind.
1. The southernmost spot in Finland is too far north, and the scramble that happened in EU at the loss of Russian energy supplies made it crystal clear that we can not trust any other country to help in times of need.
2. We have no geothermal sources sufficient for production of electricity, it can only be used to slightly reduce primary energy use during winter, but it will raise electricity use during winter.
3. Helps not at all, because 0 times however large number you like is still 0.
4. Likewise.
5. Improvements in efficiency do not help you stay alive when it's -30°C.
The option up here really truly is "do we use fossil fuels, or do we use nuclear". Renewables do not help. They are nice to have, and it makes sense to build them because they complement the reduced output of nuclear in summertime, and because the lower cost/kWh can help some industry, but that's all.
The difference between baseline and peak electricity consumption in Finland is >2x. That's mostly driven by heating. Because renewables make electricity cheap on the average, utility companies invest in cheap heat storage systems such as sand batteries. They use electricity when it's cheap, store the heat, and distribute it when it's needed.
As for nuclear, the challenge is finding companies that are able and willing to build it. Areva and Rosatom both failed at the "able" part. And a power company (I think it was Fortum) recently stated that they would consider building new nuclear reactors with German electric prices but not with Finnish prices.
There is more to that than a power company asking for subsidies. Finland is a small country. Olkiluoto 3 alone generates >10% of the electricity. Newer reactors would likely be smaller but still ~10% of the total. Finnish power companies are too small to take risks like that on their own. They can't build new reactors at their own risk, in order to sell the power in the market. Before a reactor gets built, the power company needs long-term commitments from industrial users and utility companies to buy power for a guaranteed price. Such commitments would make sense for the buyer with German electricity prices but not with Finnish prices.
I think this is exactly right, and people are focusing on the wrong risk with nuclear. It's financial risk, not safety risk, that is the biggest burden for more nuclear.
Finland was very very wise and savvy to get a fixed price contract for Olkiluoto 3. The final cost was far far far above its price, and France ended up paying that price. I'm not sure if you'll see a builder go down that route any time soon again.
Well that covers the financial risk from the safety risks... but even if it were purely about safety it's an act that's part of making the safety not be an issue. Unless it were not renewed, then it would be a problem agai.
>2. We have no geothermal sources sufficient for production of electricity, it can only be used to slightly reduce primary energy use during winter, but it will raise electricity use during winter.
The project for properly deep geothermal for district heating in Espoo was not resounding success. And that is 6,4km deep hole in southern part of Finland. My understanding is that it somewhat worked. But not as good as expected.
>The option up here really truly is "do we use fossil fuels, or do we use nuclear". Renewables do not help.
Hey now - renewables gave us electricity up here long before Einstein started thinking about atoms!
We are very few people here, 250MWh helps a lot, but if we have to chip in to build a nuclear plant we'll be broke before the project planning is done. ;-)
> The southernmost spot in Finland is too far north, and the scramble that happened in EU at the loss of Russian energy supplies made it crystal clear that we can not trust any other country to help in times of need.
Note that even if Central Europe did have sufficient energy for export it wouldn't really help during crisis. To get the energy to Finland it would need to either go thru the Baltic Sea via undersea cables or via Northern Sweden. We have seen that it's not necessarily good idea to rely on the former during the crisis as those lines can easily be cut, they have been multiple times in just past year or so by certain commercial ships "accidentally" dropping their anchors.
As for latter Sweden, doesn't currently have capacity for it and I don't think they have been very interested in increasing it, currently Finland often benefits from the fact that there isn't enough transport capacity between Southern and Northern Sweden electric grids so Finland gets some cheap electricity from there.
> 3. Helps not at all, because 0 times however large number you like is still 0.
Show me your Monte Carlo simulation where wind (which is negatively correlated to solar) and 8 hours of battery storage are factored in, along with small amounts of gas peaking plants.
What is also important to know is during the winter is that while production on average shows numbers every day, in practice that production comes only during the few actually sunny days in December when the panels aren't covered in snow.
Go even a bit up north from Helsinki and unless you keep your panels clear of snow manually, you'll hardly make anything between Nov and April.
We have the problem of stable high-pressure polar air masses potentially parking over the country. Whenever that happens, we get 2 weeks of dead calm, coinciding with the coldest weather that occurs in the country. At the time of the year when there is no solar.
Show one where it does work. Even in far souther countries like Poland solar production is 1/4 of what it is in summer. I'd have to fill my entire roof with solar and still would have to get some power from the network to heat my house
Right, the worst case scenario is cold temperatures, transmission problems (say days after a storm), lull, and nuclear and hydro power malfunction. However, it should be pointed out that winters are usually quite windy and there are only a few days per year you get very cold temperatures coupled with nearly no wind at all.
The system in the article works alongside gas and wood chips heating, so there are other options in place if the sand battery cannot be "charged".
FTA:
> The project will cut fossil-based emissions in the Vääksy district heating network by around 60% each year, by reducing natural gas use bu 80% and also decreasing wood chip consumption.
Not really, we're currently borderline. If OL3 goes down, and it's simultaneously cold over the nordics + northern germany and the baltics, and no wind, our industry will have to shutdown.
This would be an argument for widespread backup power, actually. If every residence had enough backup power to get through 24 hours, it would be far easier to deal with these relatively rare doldrums.
But "stable" isn't really want they want or need. They have a) cold, dark winters so they want more energy in the winter not a constant amount year round, b) hydro (89% of electricity in Norway!) that is already used as seasonal storage and can be varied to meet daily variation.
Cheap wind that produces more in winter is the obvious answer and indeed seems to be a focus of their build out.
> But "stable" isn't really want they want or need.
Yes, that is exactly what they need. They need stable energy over let's say a 1-2 week period. A windy week is often followed by a non-windy week. So if they can store the energy from the windy week and use it in the following week then they can rely on wind power as a stable energy source.
There's an interesting property to thermal storage, as a consequence of simple geometry. Consider a cube. volume = n³ and surface area = 6*n². Surface area increases more slowly than volume. The ratio of surface to volume decreases with more size. Thus: a sufficiently large thermal reservoir becomes self-insulating with its own mass.
It's even better than that. In addition to the factor of n from ratio of volume to surface area, there's also a factor of n from the increased thermal resistance of the mass of the storage volume (the temperature gradient from the surface to the center goes as 1/n). So, the thermal time constant of the object scales as n^2.
This very favorable scaling is why natural geothermal retains heat even though the input energy was delivered gradually over as much as millions of years.
I've always wondered why we don't build homes with a buried tank of water used as heat storage. In the summer it can be heated with solar thermal to around 90c, and in the winter heat can be drawn out and go through radiators or underfloor heating, with a mixer valve. You just need a few pumps and valves, not even a heat pump is needed.
If you assume a modern house with a heat load of 1800kWh per year (fairly standard for a new build medium sized home where I live, in Northern Europe) that means you'd need a tank roughly 50m3, or 10,000 gallons for Americans. In terms of insulation you'd need around 50cm of XPS foam, and it would be buried a meter below ground.
It's nothing terribly complicated in terms of construction or engineering. Of course you'd pay more upfront, but then your heating bills would be practically zero. In warmer climates it would be much simpler, you could probably get away without burying it.
This is essentially what a ground source heat pump system is. Except instead of a sealed water tank you just make a tall hole that fills with water and the sun will warm it for you during the summer automatically.
1800 kWh is very little. We use around 12000 kWh and our neighbours' new house uses around 8000 kWh annually and most of that is heating. I'm not sure how many houses can hit 1800.
A ground source heat pump (also geothermal heat pump) is a heating/cooling system for buildings that use a type of heat pump to transfer heat to or from the ground, taking advantage of the relative constancy of temperatures of the earth through the seasons.
You can also recharge your geothermal well or ground heat collection field by heating the outgoing thermal collection liquid with either cheap electricity (rooftop solar?) or direct solar heat collection. I think this will be a growing thing as the earliest mainstream ground source heat wells start to be a few decades old. Many of them are sized so that they don't fully recover during the summer, so the heat output slowly drops.
A modern house in Finland needs around 15-24kWh a year of heat energy if it's well insulated. On the higher end for big + northern houses, and less if you're smaller and further south.
Some get this energy by burning wood, others with heat pumps, and some with direct electricity.
My 90sqm bungalow in the U.K. uses about 15MWh a year for heating - 1500 litres of oil, almost all in winter. Peak load is about 2.5kW over a day (60kWh)
I think you are off by about 3 orders of magnitude as my Austrian flat need about 7MWh a year for heating and 3MWh of electricity. I could generate 24kWh per year on an indoor bicycle.
I can't find the link now, but there was an episode of Grand Designs here in the UK (a show detailing private individuals developing interesting or unusual homes) where the owner was building a passively heated house based on an idea by his architect father.
The ground beneath the footprint of the house was insulated around the sides to a depth of about 2m, effectively extending the thermal mass of the house into the ground. After construction, it took about 2 years (IIRC) to warm to a stable level, but thereafter required little to no energy to stay at a comfortable temperature year round.
I remember that one, but also can't find a link. Wasn't the heat from the people living there, and from appliances etc. enough to keep it at a comfortable temperature?
> I've always wondered why we don't build homes with a buried tank of water used as heat storage. In the summer it can be heated with solar thermal to around 90c, and in the winter heat can be drawn out and go through radiators or underfloor heating, with a mixer valve. You just need a few pumps and valves, not even a heat pump is needed.
Because building houses is already expensive, and that would add significant amount, pushing it into "can't afford it in the first place". And zero ability to realistically service it means anything going wrong might make whole investment moot.
On top of that, any investment like that competes with "why not just put the money into low risk fund"
> 1800kWh per year
now factor in losses for months
now factor the fact the energy you're using for heating is one you're not using for... energy or selling
also is that heat or energy ? Because if that's "what power heat pump used", multiply that by 3-4
It's just... expensive to do it like this. Expensive enough that most people that could did the math and it wasn't mathing
I'm not sure if the 1800kWh is correct here. I'm guessing it's one of these two:
- You're talking about what heat pumps use in electricity. However, the system would store heat. If a heat pump uses 1 kWh to get 3 kWh of heat into the house, a heat based storage system needs to store the 3 kWh.
- You're confusing gas & electricity. 1800 m3 in gas would be about correct. However, that's about 9,5 kwh per m3 in heat.
There are interesting heat storage methods though, there is a long term basalt heat storage system in 'Ecodorp Boekel' in The Netherlands. It uses solar to heat during the summer and heats the homes with that in winter.
Due to size though, it only really works in 'collective' communities. The bigger the size, the more heat it can store per size.
Sounds like it didn’t go so well:
In 2020, the system started showing signs of deterioration resulting in significant maintenance issues. System components, knowledge, and technical expertise for repairs were becoming increasingly challenging to find. In response to system failures, the Drake Landing Solar Company added redundancies to the system to be sure that homes in the community were receiving heat… In 2024, a decommissioning process for the Drake Landing Solar Community began, where the majority of the 52 homes were converted to natural gas-fired furnaces.
Nowadays, solar thermal collectors are completely obsolete except in very niche applications. Solar PV is so cheap that it’s literally cheaper (not to mention much less maintenance) to wire a bunch of PV panels to a resistance hot water heater than it is to directly heat the water with thermal collectors!
> I've always wondered why we don't build homes with a buried tank of water used as heat storage
Skip the tank completely. Use the ground directly. This is what geothermal heating does.
Drill a deep hole and drop tubes into it. Use a heat pump to pump heat into or out of the ground. There is so much easily accessible thermal mass in a borehole that you don’t need to deal with a giant underground water tank
Its kind of done. Active heating systems often have the intake air go through the foundation so it heats up in summer and cools down in winter reducing both heating and cooling costs.
Not in the rock that geothermal can access. That rock is recharged by heat flow from below on a shorter timescale than that (but much longer than geothermal would extract the heat.)
As I understand it, most of the heat that was deposited by radioactive decay in the crust three billion years is still in the crust, not having had time to conduct its way to the surface, and most of heat deposited in the crust even today is from radioactive decay in rocks in the crust itself. But https://en.wikipedia.org/wiki/Geothermal_gradient#Heat_sourc... says that's wrong: "An estimated 45 to 90 percent of the heat escaping from Earth originates from radioactive decay of elements, mainly located in the mantle."
https://en.wikipedia.org/wiki/Geothermal_energy#Resources says 20% of the Earth's internal heat content is residual heat from planetary accretion 4.5 billion years ago, but of course that's mostly not in the crust. It also says, "the conductive heat flux averages 0.1MW/km²."
At the given thermal gradient of about 28°/km, a nominal thermal conductivity of 3.3W/m/K for granite (https://www.sciencedirect.com/science/article/abs/pii/S00137...), we can derive a heat flow rate, which works out to 0.09 MW/km², in good agreement with the Wikipedia number. By dividing by a nominal specific heat of 0.7J/g/K and some density estimate like 2.4g/cc, can we get a speed in meters per second? The units don't quite work out; the specific heat times the density gives us 1.7MJ/m³/K.
So I guess I don't know how I came to my conclusion, so maybe it's wrong. How did you come to yours?
Just as important here: The higher the temperature of the storage medium, the higher the fundamental limit to how much electric energy you can recover.
Put differently: If you used the same amount of energy to heat one bucket of sand by 200C (A) or two bucket of sands by 100C (B), you would be able to recover more electric energy from case A because of the fundamental Carnot Limit.
This is why sand is a good storage medium (as opposed to e.g. water), and why some solar power systems work with molten salts. Also why steam-based power plants need to operate at high pressure to be able to obtain high-temperature steam.
You speak theoretically but metropolitan areas in these countries all have those pipes in place and in use for the better part of a century.
Using heat for heating has many redeeming qualities. Heat is high entropy and it is not a good idea to "waste" low entropy energy to create high entropy energy. Many industrial processes run on heat and waste heat is generated everywhere. The systems are also cheap to run once in place.
That's a real issue, but this is for a district heating system which already exists and already faces this issue. And yet the district heating system is presumably practical.
Changing to a different central source of heating (i.e. storage) seems orthogonal.
Larger storage structures are easier to (thermally) insulate. Because geometry.
But going with larger structures probably means aggregation (fewer of them are built, and further apart). Assuming homes to be heated are staying where they are, that requires longer pipes. Which are harder to insulate. Because geometry.
I can't help but wonder how the efficiency compares to generating electricity, running that over wires, and having that run heat pumps.
The conversion to electricity loses energy, but I assume the loss is negligible in transmission, and then modern heat pumps themselves are much more efficient.
And the average high and low in February in 26°F and 14°F according to Google, while modern heat pumps are more energy-efficient than resistive heating above around 0°F. So even around 14–26°F, the coefficient of performance should still be 2–3.
So, in your scenario (heat->electricity conversion, then transmission, then electricity->heat conversion), overall efficiency is going to be 50% * 50% = 25%, assuming no transmission losses and state-of-art conversion on both ends.
25% efficiency (a.k.a. 75% losses) is pretty generous budget to work with. I guess one can cover a small town or a city's district with heat pipes and come on top in terms of efficiency.
We've got lots of heating districts around the world to use as examples. They only make sense in really dense areas. The thermal losses and expense of maintaining them make them economically impractical for most areas other than a few core districts in urban centers... Unless you have an excess of energy that you can't sell on the grid.
Geothermal heat is also not that functional in cities, you'd need so many wells so close together that you'd most likely cool down the ground enough in winter so your efficiency tanks.
I don't understand, what am I missing? The heat pump increases efficiency by having COP 2-4 right? Assuming air to air and being in, say, Denmark.
Heat (above 100C, say, burning garbage) to electricity: 50% (theoretical best case)
Electricity to heat (around 40C): 200%-400%
Net win?
The surplus energy comes from air or ground temperatures..
Yes you cannot heat back to the temperature you started with but for underfloor heating 40C is plenty. And you can get COP 2 up to shower water of 60C as well.
If the heat is stored at high temperature, but the demand (for heating buildings, say) is at lower temperature, it could make sense to generate power, then use that power to drive heat pumps. You could end up with more useful heat energy than you started with, possibly even if you didn't use the waste heat from the initial power generation cycle.
Alternately, if you are going to deliver the heat at low temperature to a district heating system, you might as use a topping cycle to extract some of the stored energy as work and use the waste heat, rather than taking the second law loss of just directly downgrading the high temperature heat to lower temperature.
High temperature storage increases the energy stored per unit of storage mass. If the heating is resistive, you might as well store at as high a temperature as is practical.
Gas-fired heat pumps have been investigated for heating buildings; they'd have a COP > 1.
I am interested if there are any cheap small scale external combustion engines available (steam? stirling? ORC?)
It can be anything between easy and impossible depending on the temperature difference. 200 C steam is easy with a commercially available turbine, but 50 C is really hard. There are things like Sterling engines that can capture waste heat but they've never really been commercially viable.
There's no way around it: We have to respect entropy.
Yes and a freezer that is only a bit larger, taller or deeper has a lot more liters of storage. Not just because it's in 3D but also because a smaller freezer still needs big sides. So, a lot more liters but only a tiny bit more energy consumption.
ps: living in an area with a high price per square meter goes against this strategy unless you manage to share a freezer
> [250MWh] held in a container 14m high and 15m wide
According to Gemini 3.0 Pro, lifepo4 is 1.5-3.5x more dense than this, which isn't bad. 250MWh is a lot of capacity for such a small land footprint. At 2MW it can power ~2000 homes for ~5 days while taking up the land footprint of ~1 home.
What's the price? And how does the price scale with capacity?
The problem seems to be heat quality - they don’t get electricity back, it’s only good for heating. (Which admittedly makes perfect sense in the winter near the North Pole.)
The issue we have in Finland is the assymetric electricity usage between winter and summer. This is driven by the need for heating.
In the past, district heating systems burned coal. Now that's out the window we haven't got enough to burn. We do burn waste products from forestry, trash and the like but there's not enough to go around before you start felling trees en-mass just to heat a city.
A lot of municipalities in Finland are now starting to play with thermal storage. There's this sand battery, but there's even more hot water storage being built and has been built.
In the medium term, winter electricity production and consumption is starting to become a bit of a risk for us.
It doesn't just make sense in the very far north, it makes sense just about anywhere that you'd have many people living close together (i.e. even a village).
Most homes don't need to have their own electricity generators, their own sewage treatment systems, or their own water wells, they hook into utility infrastructure.
In a lot of european towns and cities, heat is also a utility you can hook into, e.g. my apartment has no heating infrastructure in it, we just get all of our heat through a pipe connected to a nearby heat reservoir that's primarily loaded with waste heat from a gas power turbine. Within the next couple years though, the heat from gas power will be supplemented with the biggest heat pump in the world though [1]
It's not just a city thing though, I have friends who live in a village of 300 people in the Alps and they also have a utility district heating system in the village.
I was interested in trying to make a DIY thermal battery as a hobby experiment. Other than using thermal energy directly, I couldn't find a way to effectively convert the heat energy to electrical energy.
Peltier modules can be used to generate electricity, but they are crazy inefficient.
An efficient steam turbine is largely inaccessible to hobbiests and I am scared of steam/pressure. Though I did look at repurposing a car turbo for this purpose. There were additional issues with regulating the amount of heat you wanted to extract (load matching) and recycling waste heat.
I wondered if it was possible to use a Sterling engine, but you can't buy anything other than very small toys online and I don't have the facilities to machine my own.
Haha, would love to get something working, but I suppose I'm not smart enough to figure out an effective way to get that heat back out as usable/controlled electricity.
The answer in almost all electrical production boils down to spinning a turbine with steam (or wind). Nuclear does it, all the fossil fuels do it and ultimately heat batteries do it too. The alternative is photovoltaic or directly nuclear to electron production and then storage with chemical batteries or massive capacitors.
Most of our electrical production is based on a solution found several hundred years ago, we just made it really big and worked out how to control the heating and pressure of the steam well.
You missed thermoelectric generators that uses the Seebeck effect to generate a current between two temperature differentials. It's terribly inefficient, unfortunately.
> An efficient steam turbine is largely inaccessible to hobbiests and I am scared of steam/pressure.
Thermal electricity generation really benefits from scale and extremes. The Carnot efficiency is proportional to the temperature differential between hot and cold. Even so-called "low quality" heat from a standard nuclear rector design is far hotter than anybody should deal with at home and it only gets ~1/3 efficiency. And dealing with small turbines is really inefficient too.
This is where batteries and solar really shine. They scale so well, and are extremely economical and electrically efficient.
Heat storage works well when you get beyond the scale of individual homes, but it's hard to make it work. I'd love to see something related to heat pumps in the future for homes, but district heating, such as could be accomplished by converting natural gas systems to heat delivery, are probably required for it to make sense.
Yeah, sadly, it seems almost impossible to get anything higher than 30% efficiency (theoretically with a Stirling engine, if you can find one, haha) out of a thermal battery without extreme pressures and temperatures.
Back-of-the-napkin math felt promising. A 1kg block of sand heated to 500 degrees Celsius should contain about 100Wh of electricity. Scaling that capacity up is easy, as it's just about adding sand or temperature (+ an effective method of transporting heat across the sand - maybe sand + used motor oil?).
Assuming 80% efficiency, tariff arbitrage (buy electricity during off-peak hours and use it during high-price hours) would pay off very quickly. In my area (Australia) it would be a matter of months - but the low real-world efficiency and lack of parts make it impossible.
It could work for heating during winter, though perhaps an AC/heatpump with the condenser a couple metres underground would be better value for money.
Heat storage can work for individual homes on the shorter scale. If you heat your home with in-floor heating (lower temperature requirements) you can have ~1-2m3 buffer tank that you heat up during the night and then use the stored heat during the day to heat your home. Works very well.
This project is for district heating, not producing electricity.
In general it is true that low-grade heat is difficult to convert to electricity, and there isn't any existing mass-market device that does it. You'll have to make your own, which involves learning to machine and responding to your perfectly reasonable fear of steam and pressure with proven safety measures.
Every couple of years I look around to see if anyone is selling sterling cycle engines in the 5-10 hp range, I always find a couple neat projects but nowhere can you just buy an engine.
I assume that because there is no current market for small sterling generators nobody wants invest in tooling to make one and because there are no small sterling generators there is no market for them.
In the articles case the end use of energy is household heating, so there is no need to convert back to electricity. The whole beauty of thermal energy storage that the end use of energy in many use cases is.. heat: heating buildings, cooking, industrial heating (from food processing to iron smelting), producing steam, etc.
If you need to use heating in a cold climate, you could use your stored energy to heat the radiator of a heat pump, which would then be drastically more efficient than using normal air on the radiator.
There's a video of people doing this on YouTube. They use the ground as their heat source. https://youtu.be/s-41UF02vrU
LFP is so cheap that small-scale thermal battery makes not sense for electricity generation. Even in big scale (like OP) it mostly makes sense for heat, e.g. district heating systems, industry process heat, etc.
In a cold climate, I would expect burying it to use the ground as a natural insulator. Why was an above ground design chosen?
Specifically, does the need for heavy insulation and the active heating of the sand make the ground a less effective or even problematic insulator? Could excavating and building a below-ground foundation for a high-temperature device like this be more complex and expensive than an above-ground silo? How would permafrost conditions affect this design?
Because digging is expensive and there's plenty of land. More efficient to use the budget to build a bigger structure than to build a smaller one and dig down. Bigger structure also gives you better insulation (surface area compared to volume decreases non-linearly with increased volume).
Why do so many people do "why didn't you..." As if the engineers who designed this didn't have 1002 alternatives and went with this one for reasons of budget, politics, prior knowledge, IPR costs, skills, religious beliefs, or a million other reasons.
Why did we go to the moon when we have perfectly good vacuum chambers here at home.
The implied "my way is better" in these responses is usually the bad take on "what made this better than my way" as a question which nobody really can answer unless the OP is the engineer.
"Why does Finland not deploy ubiquitous small nuclear reactors every 25 meters and make a heated road to the north you can drive over as well as get power from if you have a power adapter for finnish plugs"
Interesting. Does anyone know what source of electricity is going to be used for this ? Probably solar but it might be also useful with coal plants or wind farms that produce even when there is not enough demand.
How are they moving the heat ?
Wind in practice. There's only few hours of sunlight in the winter during the day. There has been a surge of electric boiler buildup by district heating companies in the last few years to exploit the periods of high wind and resulting very low electricity prices.
Heat is transferred using disctrict heating networks where 65-120 C water is circulated.
No, these generally use excess power during the night and windy days to store heat.
There's not that much CHP production that there'd be excess, plus they can adjust those plants well enough that there's no unnecessary burning going on.
There's water based heat batteries (aka thermal storage caverns) that are supplied with district heat in use in other places, but this is not one of them. The article says "Polar Night Energy’s technology works by heating a sand or a similar solid material using electricity"
Most likely not solar since there’s almost no solar during the winter months. Sun comes up at 0900 and goes down at 1500 in the south. In the north it’s worse.
It's currently noon in Finland and solar accounts for 6 MW in the grid. That's about 0.05% of the total production. Nuclear is 3863 MW (~31%) and wind is 6281 MW (~50%).
What might be plentiful is wind, especially during the nights.
> "The installation will supply heat to the Vääksy district heating network and is expected to lower fossil-based emissions by approximately 60% annually, primarily through an estimated 80% reduction in natural gas consumption and reduced reliance on wood chips."
Those are the energy sources they're replacing with this tech - according to <https://reneweconomy.com.au/new-worlds-largest-sand-battery-...> it's surplus energy from renewables that will 'charge' the battery (so likely wind, hydro and solar that is produced but surplus to the grid's requirements)
I was surprised too at the 2nd sentence: "The project will have a heating power of 2MW and a thermal energy storage (TES) capacity of 250MW..."
and how a news outlet about energy could get such a fundamental unit wrong.
But given that later in the article it does revert to correct units (and the numbers are plausibly proportional), I assume it's just a typo. Strange that it hasn't been corrected even now.
"...It follows Polar Night Energy completing and putting a 1MW/100MWh Sand Battery TES project into commercial operations this summer..."
These are interesting, but the cost per kWh of storage capacity is still probably too high for true seasonal storage. Short term storage runs into competition with batteries.
I point again to Standard Thermal for an idea tailored to true seasonal storage. I wait for more news from them, particularly on their very low cost resistive heater technology.
Doesn't need to be seasonal, we have enough energy in general to go through winter. This is to help through week long cold snaps, when Finland is short on energy. Week-long storage is still eyewateringly expensive with chemical batteries.
Also the capex from sand battery goes to (mostly) local construction, while when buying chemical batteries all the money goes to china.
Not wearing out increases the time frame across which you can amortise the costs.
If option A costs $100,000/unit and needs to be replaced every 10 years, while option B costs $300,000/unit but lasts 50 years before replacement, option B is still cheaper in the long run, even factoring in interest rates.
(You can substitute "time until replacement" in the above with "time until maintenance costs exceed the original capex", and the logic remains the same.)
The big question is how much it will cost. For comparison I believe there is a heat battery in Germany using (atmospheric pressure) liquid water (98 C), 50M EUR for perhaps 20x the thermal storage capacity (versus 20 C water).
The use of sand, presumably heated to a much higher temperature than the boiling point of water, seems overkill for district heating (unless peak heat demand requires flow temperatures above 100 C). But it does reduce the volume of sand required, so the size of the storage system.
The cost is a function of the size and mass. So, more heat capacity and less mass means lower cost per mwh.
These things are extremely simple and fairly efficient. It's resistive heating (wires and spools) of a thermal mass (sand/stone) in some kind of container (a simple silo) with a lot of insulation and some pipes to heat up water. Higher temperatures mean getting the heat out is easier and that the battery will work for longer. Basically until the temperature drops below the required temperature.
> So, more heat capacity and less mass means lower cost per mwh.
Can you compare different technologies with these scaling laws? Also what are the limits of these approximations (e.g. taking temperatures to extremes tends to run into maintenance problems).
In this case the sand battery delivers 400 C steam from 600 C sand [0], via some heat exchange fluid (solar salt?) that flows next to the sand. Going through heating/cooling cycles can cause material issues, especially for larger temperature differences.
There's pipework for circulating air inside it when they want to charge/discharge it, but yes, essentially it's mostly tons of sand.
They have resistors for charging it with electricity (resistors heat the air, air is circulated in the pipes which heats the sand) when the electricity price is cheap, and then for discharging they have a air-water heat exchanger so they can pump the heat energy into the district heating network.
Likely a combination of practicality, and the importance of airflow throughout the sand in order to heat it and pull from it effectively.
Also, water's specific heat capacity is 4.186 J/g°C, while air's is approximately 1.005 J/g°C. It would take much more energy to heat up water than it would to heat up air.
Also, water boils at 100 degrees, and they store it in the sand at 600 degrees.
You use electricity (ideally cheap solar/wind) to heat air. That hot air circulates through a silo full of sand. The sand holds the heat for months. Later the heat is drawn out and used for buildings or industrial processes.
I do kind of wonder will those come back, with a slightly smarter heuristic for turning on than "it is night". They're inefficient next to a heat pump, but vastly cheaper to make and install, so with a smarter grid, they may be an appropriate sink for excess solar/wind in times of overproduction.
There wasn't much about the energy equation there. And since it's just conversation with Gemini just pasted here, I'm not sure how much to trust it and it just feels lazy and disjointed.
- embrace North Africa, admitting them as member states, and doing massive solar there, and doing massive grid expansion to carry it north. And then in top of that, will their way to sufficient storage like the rest of us.
EU does have trouble with solar seasonality, but wind is seasonally anti-correlated with solar, and the geospatial correlation between different wind turbines drops off more than linearly with distance, and the EU covers a very large land mass as-is. You can also over-build solar inside Europe to have reasonable collection during winter.
I also see no reason to admit North African states into the EU before an agreement can be reached about transporting solar. The geopolitical risks have always been about other states severing the link during a conflict with you, and less about the parties to the deal reneging. So whether Morocco or Algeria is part of the EU is quite immaterial to the risk profile.
This kind of thing really does need simulation modelling to be reasoned about properly. The one thing I am confident in saying is that these single sentence just-so stories about what is and isn't a good idea are going to be wrong, because the fundamental principle is statistical diversification, which needs to be approached through simulation rather than through words.
It's helpful to have two flavors of storage; one short term and efficient (batteries), one long term with low capex (hydrogen, thermal). The last is the most undeveloped but there are promising ideas.
I put some numbers into this, and the required power for long term storage is significantly lower than I'd have expected.
This was giving me for Germany (assuming 80GW of constant demand) under 50GW of required hydrogen turbine power (35GW of gas turbines are already installed, but only a fraction H2 ready).
Overprovisioning (wind/solar) is suprisingly high, with 180GW of wind and 440GW of solar. Currently installed capacity for those is about 30% of that.
Short-term storage capacity is a really big gap though (the model suggests 750GWh, and currently there's <30GWh installed).
In conclusion: Under pessimistic simplifications, Germany is at about 30% progress toward fully renewable electricity (but battery capacity is lagging behind).
Assuming wind/solar buildout continues at rates comparable to the last decade, this would mean zero-emission electricity in ~35 years. Could be worse. But I'm personally bracing for 2-4°C of warming, and don't think european glaciers will survive the next century...
The amount of long term storage (and the duration) depends on the balance between wind and PV.
If wind and PV have similar levelized cost of energy (LCoE), then the solution will use the lack of correlation between the two to avoid much storage. In this case, long term storage is over period of the variability of wind, which might be weeks.
But if PV is significantly cheaper than wind -- and this is where trends are going -- then long term storage becomes more for seasonal leveling, at least at high latitudes.
There's still a large place for short term storage, and economics is still strongly affected by the cost of that storage. So it's great news batteries have become so cheap to produce.
V2G can provide the short-term capacity. If one allocates e.g. 40 kWh from their battery to V2G, each million electric cars can add 40GWh of grid tied battery storage. If you pay people fairly, it will happen. There are more than 4 million electric cars in the EU already...
In Austria at least you cannot even charge your car with properly priced electricity unless you have your own outlet. At some chargers it is more expensive to charge through the night (because of blocking fees over 4-5h) even though we basically always have the lowest prices then.
Why do you say "embrace nuclear" when the EU has substantial existing and planned nuclear plants? (Current gen is something like 24% nuclear in EU, 20% in wider Europe, 18% USA, 4.4% China)
And anyway, alongside that world leading nuclear already in existence why wouldn't they just install lots of cheap solar and wind, and heat pumps and EVs and reduce their imports of energy from their current high levels (about .6 Trillion euros in 2022, down to .35 in 2024 though that seems mostly a change in price, volume has declined only slightly)
Embrace nuclear would be continuing the existing recent trend of the Germans stopping talking down to the French, and also figuring out how to build new ones in a timely matter.
Solar is pretty terrible outside of Spain, and even there the latitude is not great.
Finland's current energy equation according to Google Gemini:
Is Finland importing household garbage from Italy and why?
Gemini: ... In summary, Finland imports waste (mainly as pre-processed fuel) to feed its modern waste-to-energy plants, which are a key part of its heating and energy strategy, especially as domestic residual waste volumes decrease due to better recycling and as a replacement for former Russian renewable fuel imports.
Why you call it "processed"? It is raw garbage in huge mounds smelling bad and harboring flies and rats?
Gemini: ... This processing turns smelly, inconsistent "garbage" into a stable, high-quality, non-hazardous secondary fuel that is compliant with strict EU waste shipment and energy production regulations. The whole point of the import is to fuel power plants efficiently, which requires this specific, processed product.
Lets try again. Why the "processed" mound of garbage from Italy smells bad and houses flies and rats?
Gemini: ... Sometimes ....
This is not "sometimes", it makes living near Loviisa harbour impossible.
Gemini: ... It is clear that the environmental integrity and quality of life for residents of Loviisa have been compromised by the need to fuel Finland's waste-to-energy capacity with large, sometimes substandard, imports.
etc etc.
===
Short summary: The Pro-Russian Green "Pedophile"-Party destroyed the existing energy infrastructure which ran on coal from Poland etc.
A new system was built to use "renewable" Russian gas and Russian wood industry leftovers.
The situation is desperate; any shit from anywhere at any cost is better than using local renewable biomass, such as peat.
Finland has enormous amounts of peat, which is worth more than Norway's oil reserves.
Calling Green Party "Pro Russian" is ridiculous. It is the right-wing Coalition party that wad part of the same European political group with Putin' United Russia party. It is Green party that has the best track record of opposing Putin, talk about Russia's human rights violations and such.
Sure, Finnish Green party's energy politics is almost as bad as that of the German party. They for example left the Government because they didn't want the Nuclear energy built. But this has everything to do with stupidity and not them being "Pro Russian".
Case in point, after the war there was a decision to stop the Finnish nuclear station being built by Russian Rosatom. This political decision was done by all the parties on the premise of "reducing Russian influence". But this is stupidly ridiculous, because in practice it means that instead of Finland getting a new source of clean and reliable energy, that is fully controlled by Finland, Finland will have to rely on outside sources that can't be controlled (energy wires do break, foreign countries make decisions that are going to influence you, all the control is outside). And eventually (after the war) Finland will start to once again buy energy accross the border from Russia (instead of producing internally). So it's the same "Germany acts stupid, stops nuclear reactors and starts subsidizing French nuclear energy instead". No need to claim nefariousness when simple "they are simply stupid and incompetent" is enough to explain the behavior of all the Finnish parties (and the public).
Hey @grok. Is there some grounds to call the Green Party a Pedophile Party?
Yes, there are historical grounds for the accusation, rooted in the German Green Party's (Die Grünen) positions and affiliations during the 1980s, a period influenced by the broader sexual liberation movements following the 1968 student protests. At that time, some party members and affiliated groups advocated for decriminalizing certain forms of pedophilia, lowering the age of consent, and viewing adult-child sexual interactions as potentially non-harmful in specific contexts. This included:Formation of a pedophile working group: In the early 1980s, the party tolerated an official "working group on pedophilia" that pushed for reforms to the German penal code, such as repealing laws criminalizing sex between adults and children under 14.
dw.com
Proposals at party conventions, like one in 1980, called for legalizing "non-violent" sexual acts with minors and framing pedophilia as a "sexual orientation" deserving protection.
spiegel.de
Key figures and statements: Prominent members, including future European Parliament leader Daniel Cohn-Bendit, made controversial remarks; in a 1982 TV appearance, he described playful sexual interactions with young children as an "erotic-manic game" based on his experiences as a kindergarten teacher.
dw.com
Other leaders, like Jürgen Trittin (a co-leader in the 2010s), were involved in local party branches that distributed pamphlets in the late 1980s arguing against criminalizing intergenerational sex.
spiegel.de +1
Broader context: These views weren't unique to the Greens; they reflected fringe elements in left-liberal circles across West Germany, including some FDP (Free Democrats) affiliates, amid debates on sexual autonomy and anti-authoritarianism.
For reference, this city is about as north as Anchorage Alaska and today they got less than 7 hours of sunlight and it'll continue to decrease for the next 3 weeks.
The Nordic countries generally still wants to increase their wind and solar power, but the big issue during winters is when there's cold air high pressure systems we get neither sun nor wind, having an energy storage that can hold up to 5 days worth of energy should help us nudge past them.
Hydro-energy exist (mainly Sweden and Norway, but I think some in Finland as well), but it's fairly built out so stable non-fossil power needs to be nuclear, or wind/sun + storage (that hasn't been good enough so far).
One of the interesting things about hydro is that it's usually constructed to satisfy baseload power. In reality, shifting that over to a peaking plant requires relatively modest changes to system, a small fraction of the cost of an entirely new dam. You don't actually need the "Pumped" part of pumped hydro, you can just throttle normal hydro on and off if you have enough turbines (though for ecological & geomorphological reasons some minor downstream damming also helps). There wasn't any reason to install the extra turbines in the age of fossil fuels. They only take ~30 seconds to spin up, versus days or weeks for thermal plants.
> You don't actually need the "Pumped" part of pumped hydro, you can just throttle normal hydro on and off if you have enough turbines (though for ecological & geomorphological reasons some minor downstream damming also helps).
Yeah that generally can work for a week or so, not for entire season.
Imagine if we build hydro to full capacity and monetize the excess with data/compute centers and/or crypto mining. We'd have so much spare capacity for any residential or industrial purposes.
Datacenters and crypto are evidently a bad source for large-scale load variability because their significant capex demands that they be kept running 24/7.
This is often a problem with variable load schemes that do any useful work, rather than just dumping heat into something. It would be interesting to see a list sorted by just how thick they are with capital considerations. Aluminum smelting, hydrogen electrolysis, lots of other options on that list.
> their significant capex demands that they be kept running 24/7.
US companies are sitting on a pile of not yet connected GPUs because they have no place to put them. They would take 10 out of 24h if they could get 10. It's better than zero that they currently have for those GPUs.
Same with crypto. No point of running a rig if it's losing you money becaus electricity is too expensive at this moment. Regardless of capex sometimes it's better not to run it.
> “Hydro-energy exist, but it's fairly built out so stable non-fossil power needs to be nuclear, or wind/sun + storage”
Interconnectors also exist (and more are planned), which means, for example, that Norway can buy wind energy from the UK when it’s cheap and abundant, in preference to using stored energy from their hydro lakes.
That way they effectively get more out of existing hydro lakes, which in Norway is already a very significant storage capacity.
Theres not going to be built any more interconnectors from Norway anytime soon.
Electricity became a lot more expensive in Norway after building several interconnectors to UK and mainland Europe. Importing high prices from the failed energy politics of UK and Germany which both have among the most expensive electricity in the world.
This has been a huge debate, and the general concensus seems to be that joining ACER and building inrerconnectors to mainland Europe was a big mistake.
Does that mean Norway is making a huge amount of money exporting electricity over those interconnections?
Yes. But that is money the consumers don't see.
About 90% of Norway's 40 GW energy production (mostly hydro) is state owned. By exporting energy and thereby getting other countries to pay, the money literally goes to the norwegian people. Not directly into their bank accounts, but into their govt budgets, which they later pay less in taxes.
Norwegian power generation is sized for the domestic market, so tax income from selling excess is marginal at best. The power bills however have indeed crept quite a way up. This was especially noticeable in the first winter of the Russian invasion, when the Nordics had to subsidize the bill that suddenly dropped on short-sighted German energy policy.
Germany benefits a lot from the open market. If only countries introduced a rule to export only the excess of the energy then Germany would be cooked, because prices would sky rocket for them, not 2x, 3x, but way more. Luckily for them they can make strategical mistakes and go away with it making others to pay for that.
Right, but people tend to be oblivious to anything that's not on their bank accounts.
i think that doesn't hold true as much in norway and scandinavia in general.
as varjag said: "there's a social consensus about the value people get from this taxation level"
Until it's taken away, of course.
Example, the Netherlands had the biggest gas reserve in forever. It's 2/3rds or 3/4ths empty now and extraction has or is stopping due to it causing earthquakes. But the income from exporting the excess gas has been used for socialist policies. Now that that income is gone, and now that expenses for gas have gone way up (also due to reliance on cheap Russian gas), people are feeling it in their bank accounts directly and the socialist policies are being dismantled one by one.
Do they actually pay less in taxes because of this? I’m not arguing. That is great and I would appreciate if you could provide a source for me to read.
We do not but there's a social consensus about the value people get from this taxation level. However the excess power price which is not a domestic supply/demand outcome is a lot harder to sell.
Their tax rate is already pretty high. But yes it effectively sponsors their entire energy infrastructure
There are government subsidies for consumers to either have a fixed price or a price cap on electricity in Norway as a political response to the increase. This would be harder to pull off if not most of the profits from export didn’t land in the public sector (either taxes or government owned energy companies).
Norway has experience circumventing the resource curse/Dutch disease with undersea oil. Hopefully they'll manage it this time too.
> Importing high prices from the failed energy politics of UK
Remember that its a market, not the consumer price.
The spot price for UK electricity is still quite competitive in the winter, just not reliable.
The other thing to note is that peak in the UK is different to peak further up in longitude, which means that there is benefit to both countries for this.
That seems counterintuitive to me.
Electricity prices don't go up because you have access to expensive power, it goes up because you don't have enough cheap power so you have to buy the expensive power.
It seems like Norway just wouldn't have power if they weren't connected to other sources, not that they'd have more cheap power.
Electricity prices go up when you have access to customers who are willing to pay more. If grid connections to other regions are limited, people in regions with a lot of cheap generation (such as Norway) pay low prices. But if you add grid connections without increasing generation capacity, prices start equalizing between regions, as every power company tries to sell to the highest bidder.
Norway could power itself fully with domestic hydro. But it chose not to, as the power companies make more money by importing foreign power when it's cheap and exporting hydro when it's not.
Washington state has the same problem to a lesser degree. California pays more for cheap Washington hydro, which causes the costs to go up for us, although I guess not as drastic as Norway since our electricity is still considered cheap.
Norway still have cheap electricity in the grand scheme. It is just more expensive than it used to be.
> "Norway could power itself fully with domestic hydro." We have events where the we cannot get enough load from domestic production. Typically in winter when water freezes.
> It seems like Norway just wouldn't have power if they weren't connected to other sources, not that they'd have more cheap power.
This is not the case as Norway and neighbouring Sweden have plentiful hydro. It's especially valuable as it can be regulated to complement wind/solar fluctuations, essentially replacing storage.
Obviously the presumably large amount of money spent to interconnect could have been spent adding local production and storage. It would be a waste of money if there was a reasonable path to local energy independence that was neglected.
A significant proportion of Norway's domestic energy production is hydro, which comes with it's own "built in" storage up to the capacity of the dams, so Norway already has a very significant storage capacity.
Estimates suggests a storage capacity of 87TWh of storage in hydro reservoirs, compared to production capacity in recent years between 146 and 157 TWh, and a theoretical production capacity of ~309TWh (I don't know the basis for that - I'd imagine peak production at all the plants, but I doubt that could ever happen in reality, so the 146-157TWh based on real production are better...)
Compare that to Norwegian electricity consumption of 124 TWh in 2020.
Of course, since so much of Norways total electricity production is hydro, large storage is necessary, as the hydro supply is highly seasonal, based on e.g. things like the amount of melting snow in the mountains in spring.
but they have enough cheap power
they have too much cheap power, so they decided to sell it. But the fact they have a buyer that buys for more than locals, means they do not longer have to sell to locals at low price.
Tho it being state owned make it weird, you'd think state would keep lower rates for the people
Prices went up in norway because the uk had even higher prices than norway. Having these interconnections is good for producers in norway and consumers in Uk, but very bad for consumers in Norway
It’s basic supply and demand. And by linking to other grids, you increase demand since there’s now more customers for your supply. What they have (comparatively) less is supply since the supply in those markets is shite in comparison to what Sweden and Norway have for their local demand.
> Norway can buy wind energy from the UK
Even Southern England cannot get enough wind energy from Scotland to fully utilise wind farms because transmission capacity is insufficient. I would imagine a transmission line to Norway will be even more expensive than to England.
Solving the Scotland/England interconnect under-capacity is well underway https://en.wikipedia.org/wiki/List_of_high-voltage_transmiss...
But they are building such a link, because it'll make/save more money than it costs.
Imagine how many doom and gloom headlines we'd have avoided if these two massive construction projects could have been sync'd up perfectly or if we had a national press that could do anything other than try to scare people with big numbers.
The interconnects already exists.
> the big issue during winters is when there's cold air high pressure systems we get neither sun nor wind
Wind does better in the winter.
See eg here for Canada monthly stats: https://www150.statcan.gc.ca/t1/tbl1/en/tv.action?pid=251000...
Also, wind does better at night than day, which may be related or not.
I think the point is that winter can create periods where there is neither adequate wind or adequate sun. Having strong wind production at some times will only be good if there's a way to store the excess. That's exactly what this project does and I believe that was GPs point.
And in Finland: 60% of Finnish wind energy 'collected' in the winter months (Oct-Mar)
https://suomenuusiutuvat.fi/en/wind-power/wind-power-in-cold...
> there's cold air high pressure systems we get neither sun nor wind
AKA https://en.wikipedia.org/wiki/Dunkelflaute
Hydro energy generation is fairly built out, but the Nordics have lots of places suitable to build out hydro energy storage. Hydro generation requires a flow to dam, but storage doesn't.
We don't really. Hydro storage requires reservoirs where you can freely adjust the water level. Most of our lakes have shorelines that have been built out, and the property owners get really angry if you suggest frequently adjusting the water level significantly.
The largest planned hydro storage projects are using decommissioned mines, and those are going to run out quickly.
You could just build a back-channel for the existing hydro-dams? Those reservoirs are only full for a short period and that is when you dont need pump energy.
But where? In Finland, at least, the land is relatively flat when compared with Norway and Sweden, and with a large rural population there aren't really any good locations.
In my local area, we had major flooding this spring because the hydro plant operators were sleeping on the job (or whatever they did instead of regulating water levels). And that was a simple 2m increase in water levels.
NO/SE have some more geographically suitable locations, but last time I checked, flooding them was considered too environmentally destructive too the local environment.
Yeah, you're right regarding the environmental concerns.
Most of Norway's hydro dams were built a long time ago when there was little focus on the environmental effects.
The last major plant went live in 1993. Most of the focus now is on far smaller schemes, that doesn't really add up to a lot compared to Norway's established generating capacity (which outstrip the total electricity use anyway), but which also meet far less opposition.
Part of the reason for that was growing local opposition to larger plants, and sometimes national opposition, culminating with the Alta controversy[1] in the late 70's that were some of the largest civil protests in Norway since the end of WW2. The protests eventually failed, but it had a lasting effect on Norwegian politics.
[1] https://en.wikipedia.org/wiki/Alta_controversy
If you pump the water back into the existing reserviors you will have less flooding?
I suggested a pump-water extension to existing hydro power reservoirs.
Like your EV recharges when you release the pedal.
Right shouldn't talk about EVs with a Finn, that analogy will not fly. Ok, like if you plan carefully where you throw up your koskenkorva you can re-use it.
The reservoirs in Finland aren't quite at the scale your Explorer Vodka-fuelled Swedish mind believe them to be. Most are small generators hooked up to the local rivers, and are required to prioritize keeping the water from flooding residential areas.
There's a reason we're looking at using old mines for pumped hydro rather than trying to pump water upriver during a spring flood because other power sources have surplus generation.
You could use the ocean for the bottom level and an artificial reservoir for the top level. You're not going to noticeably affect ocean levels.
Or just use a large lake. You're not going to noticeably affect the water levels of a large lake. You might pump 10 billion litres of water, which is .02% of the volume of Mjøsa.
The problem is where to store it.
10 billion liters of water is 1,000 m^2 * 10m deep. There is no suitable location for that that is both elevated enough and near enough to Mjøsa to be financially viable.
Norway also existing hydro reservoirs with a capacity equivalent to around 6-8 months electricity supply, so it's not really a major need for Norway, anyway, but this is a fairly general problem: Finding suitable locations that are close enough to a water source, and provides a large enough potential reservoir is hard.
> Finding suitable locations ... is hard.
No it's not. Here's almost a million of them: https://re100.eng.anu.edu.au/global/
If big ones are hard, you can make a bunch of smaller ones.
Looking at a few of them, a few obvious problems are apparent.
Firstly, it takes a rather liberal idea of how close the basins need to be to each other to be viable.
Secondly, most of the ones I looked at would require extensive relocation of existing populations and/or large-scale infrastructure changes, such as re-routing important roads.
The first few I looked at also do not have a sufficient water supply nearby - you'd face either covering them or you'd quickly run into problems of evaporation that you have little ability to replenish/replace.
A lot of the ones I quickly looked at would also face "fun" issues such as no nearby infrastructure such as roads to bring in construction materials.
I have no idea how many suitable locations there are on that map, but it seems pretty apparent it is a small fraction of the ones marked before you even consider how many would be politically unviable because of public resistance to the environmental destruction.
To be clear, I'm not at all opposed to investigating pumped storage, but it's also not nearly that simple.
> You could use the ocean for the bottom level and an artificial reservoir for the top level. You're not going to noticeably affect ocean levels.
Then you have to deal with the problem of sea water corroding everything it touches.
> You might pump 10 billion litres of water, which is .02% of the volume of Mjøsa.
It's not the amount of water that you pump, it's the amount * the elevation delta. Where are you planning on getting the elevation delta from?
Neither of these challenges is technically insurmountable, but this is a field where capex + opex/KWH is everything.
> Where are you planning on getting the elevation delta from?
Elevation delta is not hard to find in Norway! A typical pumped storage facility uses 100m of delta; I imagine Norwegian ones would use more.
> but this is a field where capex + opex/KWH is everything.
And pumped storage is significantly cheaper for seasonal storage than any proposed alternatives.
The original post is efficient for heat storage, but converting low grade heat to electricity is not efficient.
> And pumped storage is significantly cheaper for seasonal storage than any proposed alternatives.
This is incorrect. There is currently not a single pumped hydro station that is suitable for seasonal storage. They're all designed to drain their upper reservoir in 4-16 hours.
It's the only thing that's half economical. Do the math: Even a modest power plant - 1 GW output - that can run for 1000 hours means you need a 1 TWh (even typing it feels ridiculous) storage reservoir. If you only have 100m of head, that's 3 cubic kilometers of water. That would mean building an artificial lake that immediately would be Norway's 6th largest body of fresh water, and draining it completely every winter.
And effectively, you'd have to build it twice - you also need a lower reservoir. Because there's nowhere to get 3 cubic kilometers of fresh water to fill it otherwise, and you really don't want to do pumped hydro with seawater.
And yet it's still far cheaper than any other form of seasonal storage.
Seasonal storage is crazy expensive. You need a lot of power, and a lot of energy, but you can only amortize the cost over one or two usages per year.
Norway already have seasonal storage with a storage capacity equivalent to 6-8 months of total electricity use in the form of its existing hydroelectric plants, with no need to pump things back up again.
> And yet it's still far cheaper than any other form of seasonal storage.
Only for countries with very suitable landscape, and the willingness to use it - damming high altitude valley is extremely unpopular and bad for the environment.
Also, pumped hydro is expensive. Initial capex is higher than today's lithium batteries, if you design comparable systems. The only reason anybody is still building new pumped storage is that you can use it for 100 years (instead of 20 for the batteries, although nobody really knows how much they'll actually degrade).
I think we'll find hundreds of TWh of seasonal storage elsewhere. Thermal storage is extremely attractive if (or once) you have district heating installed. Takes care of a massive junk of domestic heating, and could take over light (food processing, paper,... ) and medium (chemical, ...) industry. Just don't try to turn it back into electricity...
Once steel and concrete get electrified, we might get seasonal hydrogen storage in underground salt caverns. Concrete and steel need absurd amounts of high heat which probably means making lots of hydrogen, putting those in the right locations might make additional hydrogen for fuel cells/gas turbines available, relatively cheaply (still extremely expensive, seasonal storage always is). But who knows...
For some applications, you don't actually convert the heat to electricity.
This sounds pretty cheap if it works out:
https://austinvernon.site/blog/standardthermal.html
> A typical pumped storage facility uses 100m of delta
Most projects seek 200-600m. This map doesn't even consider pumped hydro <200m: https://maps.nrel.gov/psh
> And pumped storage is significantly cheaper for seasonal storage than any proposed alternatives.
Based on what? Cost is particularly variable for pumped hydro. It can be one of the cheaper options when stars align. But you need 1) a suitable geography that minimizes the cost of damming or digging a resivoir with sufficient head 2) available for development without too much backlash 3) Near enough grid resources to minimize infrastructure and line losses. I'm surely leaving pieces out.
It can be cheap, but it has far more hoops to jump than alternatives like batteries, hot sand and other "storage-in-a-building" designs which can be built where needed and using fairly standard industrial construction.
True, but that disrupts ecosystems. Or so the argument against go building storage dams go.
That said, there's been a fair bit of talk here in Norway recently about tax incentives blocking hydro owners from upgrading old generators, improving efficency. Apparently a lot of currently unused power available if they "just" did that.
I think hydro storage is a lot less disruptive because you don't need as much space. Traditional hydro reservoirs have to last all season.
I wonder if it's possible to also increase the amount of generation on existing dams? I could imagine there being situations where there's excess peak flow capacity but it isn't utilized because the flow rate would be unsustainable. But if we're looking for storage it could make sense.
Hydro doesn't work so well when things freeze over. Geothermal on the other hand...
It doesn't get cold enough for long enough for lakes to freeze solid.
Some of the hydro power is run-of-river hydro power stations, which has lower flow when it is cold.
I imagine the thaw/freeze cycle would be hell on the equipment to run pumped hydro storage.
Are there extant succesful examples of pumped hydro in cold regions?
You have Juktan in northern Sweden which was pumped hydro from 1978-1996, and now they want to re-build it back into pumped hydro again https://sv.wikipedia.org/wiki/Juktans_kraftstation
A reversable pump-turbine is not significantly different from a standard hydro generation turbine, and there are tons of examples of those operating in cold regions.
> Are there extant succesful examples of pumped hydro in cold regions?
There's some pumped hydro at Niagara falls in Canada, which is far enough North that it should see a bit of a that/freeze cycle but is still a relatively mild climate.
Don't know anything about what issues this does/doesn't present to them, just happen to know it exists.
For reference, Niagara Falls is at roughly the same latitude as Barcelona and Milan. Vääksy, Finland, is approximately 1,250 miles (2k km) north of there, slightly north of Anchorage, Alaska.
Latitude is a poor point of comparison here, North America tends to be substantially colder than Europe at the same latitude.
Or concretely Niagara Falls goes from an average low of -6.44 C in February to 21.0 C in July. Barcelona an average low of 4 C in January to 20.2 C in August (according to the internet).
But yes, it's warmer than Finland, just cold enough to see something of a freeze that cycle.
A couple days of -6 is probably a lot easier. Its probably still economical enough to heat the equipment on the days below 0. I imagine having a couple months of -20 is a bit different.
Surely the turbines could be fed from subsurface water that is not frozen.
There's not much geothermal available when you are standing atop the baltic shield.
Either fusion or drill baby drill is necessary. Watt’s steam engine was absolutely horrible, but it was the worst steam engine ever built. If Finland builds the worst deep geothermal ever that still works, we can hope for better ones.
Yeah I know drilling through ~8-10 kilometers of rock is kinda hard… they know, they tried, maybe it now is a good political climate to try again?
> Yeah I know drilling through ~8-10 kilometers of rock is kinda hard… they know, they tried, maybe it now is a good political climate to try again?
The Finnish 7 kilometer geothermal drilling failed commercially, I guess that's what you're referring to. Is there any reason to assume drilling deeper would work?
Ref. https://fi.wikipedia.org/wiki/Otaniemen_syv%C3%A4rei%C3%A4t
Yeah, that’s the one. Economics of this are hard - but money is numbers in computers, it’s just a question of how serious the government is with getting it done - physics-wise it gets like 10-15C warmer with every km, which is important for the delta T obviously. I know nothing about drilling the extra couple km, though, only assuming it can be done with enough engineering.
I understood that temperature wasn't the problem. How it works is that you pump water into one well, and get it out from an adjacent one. The main problem was permeability, they couldn't get the necessary flow rate between the wells.
Ah good to know, I for some reason thought it wasn't hot enough. Sounds like they need to figure out horizontal drilling 8km deep in volcanic rock.
Or just fission, we know how to do that.
8-10km is not anywhere enough, the Baltic Shield is ~50km thick.
You don’t need to drill to magma, just deep enough to get to 120-130C rock. (‘Just’)
They tried in southern Finland not long ago. At great expense and spending a lot of time they managed to drill down 6-7 km until they figured out that the porosity of the rock down there was so poor that it was impossible to make the project economical, so it was cancelled. The idea was to pump this heat directly into the district heating grid.
That hydro is regularly turned off when it gets too cold.
Really? How do they turn it off? Where can I read about it?
I often pass the hydro bridge, so we have winters and whatnot - I didn't know they turn them off.
I can see hydro pumping power for all year long and being the top source of electricity in Latvia: https://www.ast.lv/en/electricity-market-review?year=2025&mo...
invest in saving/harvesting energy. Better than producing when solar is cheap as hell and you get no-solar-harvesting because of your location
> but it's fairly built out so stable non-fossil power needs to be nuclear,
Or just gas turbines running on decarbonized fuels. The backup for the "10 year winter" can be fossil fuels. It is such a minuscule problem that it does not matter in the slightest.
It is essentially the emergency reserve we are talking about, no point wasting tens of billions in subsidies per new built nuclear reactor.
Those "10 year" winters seems to appear every year with producers falling back to burning fossil fuels to keep the grid working.
Now part of that problem is that we more or less constantly export electricity to Germany (but that was because they closed their nuclear plants).
The main problem domestically in Sweden is that 30% of current electricity generation in Sweden is nuclear, but the _newest_ plants are 40 years old, on top of that the electricity generation needs to increase, steel mills de-carbonizing, more electric cars and so on.
For a few hours leading to insignificant emissions.
> Now part of that problem is that we more or less constantly export electricity to Germany (but that was because they closed their nuclear plants).
We have previously imported way more. The problem nowadays is that carbon emissions are expensive and even more so when coming from LNG rather than pipeline from Russia.
In other words: our prices were previously more aligned with Germanys because ours were more expensive and Germanys was cheaper.
If you are Swedish, or understand Swedish following from the "we", take a look at this talk starting at 43:40 to understand where the prices are coming from:
https://play.mediaflow.com/ovp/16/88PEO8YFIF
> The main problem domestically in Sweden is that 30% of current electricity generation in Sweden is nuclear, but the _newest_ plants are 40 years old, on top of that the electricity generation needs to increase, steel mills de-carbonizing, more electric cars and so on.
And new built nuclear power won't be online until the 2040s. Are you saying that we should wait until the 2040s to decarbonize those parts of the economy rather than do it ASAP with renewables and storage?
The existing nuclear power fleet has now targetted their maintenance on operation until the 2060s, so it is not like it will disappear overnight.
I'm not ruling out Nuclear in general, but let's remember that:
* Energy can also be carried northward from other areas in the same country or neighboring countries, where there are more sunlight hours or more wind.
* Geothermal energy sources, e.g. https://www.rehva.eu/rehva-journal/chapter/geothermal-energy...
* Increase in solar panel farm area
* Improvements in panel efficiency (which continue)
* Improvement in energy use efficiency
... in some combination, and with decent storage, might get even the Nordic countries to cover their needs.
1. The southernmost spot in Finland is too far north, and the scramble that happened in EU at the loss of Russian energy supplies made it crystal clear that we can not trust any other country to help in times of need.
2. We have no geothermal sources sufficient for production of electricity, it can only be used to slightly reduce primary energy use during winter, but it will raise electricity use during winter.
3. Helps not at all, because 0 times however large number you like is still 0.
4. Likewise.
5. Improvements in efficiency do not help you stay alive when it's -30°C.
The option up here really truly is "do we use fossil fuels, or do we use nuclear". Renewables do not help. They are nice to have, and it makes sense to build them because they complement the reduced output of nuclear in summertime, and because the lower cost/kWh can help some industry, but that's all.
The difference between baseline and peak electricity consumption in Finland is >2x. That's mostly driven by heating. Because renewables make electricity cheap on the average, utility companies invest in cheap heat storage systems such as sand batteries. They use electricity when it's cheap, store the heat, and distribute it when it's needed.
As for nuclear, the challenge is finding companies that are able and willing to build it. Areva and Rosatom both failed at the "able" part. And a power company (I think it was Fortum) recently stated that they would consider building new nuclear reactors with German electric prices but not with Finnish prices.
There is more to that than a power company asking for subsidies. Finland is a small country. Olkiluoto 3 alone generates >10% of the electricity. Newer reactors would likely be smaller but still ~10% of the total. Finnish power companies are too small to take risks like that on their own. They can't build new reactors at their own risk, in order to sell the power in the market. Before a reactor gets built, the power company needs long-term commitments from industrial users and utility companies to buy power for a guaranteed price. Such commitments would make sense for the buyer with German electricity prices but not with Finnish prices.
I think this is exactly right, and people are focusing on the wrong risk with nuclear. It's financial risk, not safety risk, that is the biggest burden for more nuclear.
Finland was very very wise and savvy to get a fixed price contract for Olkiluoto 3. The final cost was far far far above its price, and France ended up paying that price. I'm not sure if you'll see a builder go down that route any time soon again.
> It's financial risk, not safety risk
If that's the case, then why does the indistry demand the repeated renewal of the Price-Anderson Nuclear Industries Indemnity Act?
Well that covers the financial risk from the safety risks... but even if it were purely about safety it's an act that's part of making the safety not be an issue. Unless it were not renewed, then it would be a problem agai.
>2. We have no geothermal sources sufficient for production of electricity, it can only be used to slightly reduce primary energy use during winter, but it will raise electricity use during winter.
The project for properly deep geothermal for district heating in Espoo was not resounding success. And that is 6,4km deep hole in southern part of Finland. My understanding is that it somewhat worked. But not as good as expected.
>The option up here really truly is "do we use fossil fuels, or do we use nuclear". Renewables do not help.
Hey now - renewables gave us electricity up here long before Einstein started thinking about atoms!
We are very few people here, 250MWh helps a lot, but if we have to chip in to build a nuclear plant we'll be broke before the project planning is done. ;-)
> The southernmost spot in Finland is too far north, and the scramble that happened in EU at the loss of Russian energy supplies made it crystal clear that we can not trust any other country to help in times of need.
That's the failure of European union
Note that even if Central Europe did have sufficient energy for export it wouldn't really help during crisis. To get the energy to Finland it would need to either go thru the Baltic Sea via undersea cables or via Northern Sweden. We have seen that it's not necessarily good idea to rely on the former during the crisis as those lines can easily be cut, they have been multiple times in just past year or so by certain commercial ships "accidentally" dropping their anchors.
As for latter Sweden, doesn't currently have capacity for it and I don't think they have been very interested in increasing it, currently Finland often benefits from the fact that there isn't enough transport capacity between Southern and Northern Sweden electric grids so Finland gets some cheap electricity from there.
That's true, but it doesn't matter. It's not something we can change.
I don't think it's necessarily a failure of the EU for member states to prioritize stability and independence of their electrical grid.
Texas having their own grid is not a failure of American federalism.
> 3. Helps not at all, because 0 times however large number you like is still 0.
Show me your Monte Carlo simulation where wind (which is negatively correlated to solar) and 8 hours of battery storage are factored in, along with small amounts of gas peaking plants.
You don't even need to open up R or Pandas to understand that solar is not viable in the winter.
Here's the official meteorology insitutions sunshine data: https://www.ilmatieteenlaitos.fi/1991-2020-auringonpaiste-ja...
Here's some solar production data over the seasons in visual form: https://profilesolar.com/locations/Finland/Helsinki/
What is also important to know is during the winter is that while production on average shows numbers every day, in practice that production comes only during the few actually sunny days in December when the panels aren't covered in snow.
Go even a bit up north from Helsinki and unless you keep your panels clear of snow manually, you'll hardly make anything between Nov and April.
EDIT: Here's a reddit thread where someone shares real production data: https://old.reddit.com/r/Finland/comments/1i6onkk/solar_ener...
In case people want to play with a toy model: https://model.energy/
We have the problem of stable high-pressure polar air masses potentially parking over the country. Whenever that happens, we get 2 weeks of dead calm, coinciding with the coldest weather that occurs in the country. At the time of the year when there is no solar.
That's where inter-country interconnects, storage and gas come in, which can only be reasoned about through simulations.
> That's where inter-country interconnects
Recent experience has shown that we need to have our power generation on our soil. That is not something that can be compromised on.
> storage
Weeks of storage would be hilariously more expensive than just building more nukes.
> gas
Our main source of gas was Russia. Enough said.
These weather systems are quite big indeed. It's cold and calm in the neighboring Scandinavian countries as well and typically in Central Europe too.
Show one where it does work. Even in far souther countries like Poland solar production is 1/4 of what it is in summer. I'd have to fill my entire roof with solar and still would have to get some power from the network to heat my house
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Right, the worst case scenario is cold temperatures, transmission problems (say days after a storm), lull, and nuclear and hydro power malfunction. However, it should be pointed out that winters are usually quite windy and there are only a few days per year you get very cold temperatures coupled with nearly no wind at all.
"there are only a few days per year you get very cold temperatures coupled with nearly no wind at all"
This is a terrible handwave. How many days per year, in the middle of winter, in a cold country, are you OK with having no power?
The system in the article works alongside gas and wood chips heating, so there are other options in place if the sand battery cannot be "charged".
FTA:
> The project will cut fossil-based emissions in the Vääksy district heating network by around 60% each year, by reducing natural gas use bu 80% and also decreasing wood chip consumption.
Not really, we're currently borderline. If OL3 goes down, and it's simultaneously cold over the nordics + northern germany and the baltics, and no wind, our industry will have to shutdown.
Why no power? The forests, hydro dams, heat plants and such that gave power long before wind became a thing are still there.
This would be an argument for widespread backup power, actually. If every residence had enough backup power to get through 24 hours, it would be far easier to deal with these relatively rare doldrums.
Please read the hn guidelines and reconsider your participation.
But "stable" isn't really want they want or need. They have a) cold, dark winters so they want more energy in the winter not a constant amount year round, b) hydro (89% of electricity in Norway!) that is already used as seasonal storage and can be varied to meet daily variation.
Cheap wind that produces more in winter is the obvious answer and indeed seems to be a focus of their build out.
> But "stable" isn't really want they want or need.
Yes, that is exactly what they need. They need stable energy over let's say a 1-2 week period. A windy week is often followed by a non-windy week. So if they can store the energy from the windy week and use it in the following week then they can rely on wind power as a stable energy source.
There's an interesting property to thermal storage, as a consequence of simple geometry. Consider a cube. volume = n³ and surface area = 6*n². Surface area increases more slowly than volume. The ratio of surface to volume decreases with more size. Thus: a sufficiently large thermal reservoir becomes self-insulating with its own mass.
It's even better than that. In addition to the factor of n from ratio of volume to surface area, there's also a factor of n from the increased thermal resistance of the mass of the storage volume (the temperature gradient from the surface to the center goes as 1/n). So, the thermal time constant of the object scales as n^2.
This very favorable scaling is why natural geothermal retains heat even though the input energy was delivered gradually over as much as millions of years.
I've always wondered why we don't build homes with a buried tank of water used as heat storage. In the summer it can be heated with solar thermal to around 90c, and in the winter heat can be drawn out and go through radiators or underfloor heating, with a mixer valve. You just need a few pumps and valves, not even a heat pump is needed.
If you assume a modern house with a heat load of 1800kWh per year (fairly standard for a new build medium sized home where I live, in Northern Europe) that means you'd need a tank roughly 50m3, or 10,000 gallons for Americans. In terms of insulation you'd need around 50cm of XPS foam, and it would be buried a meter below ground.
It's nothing terribly complicated in terms of construction or engineering. Of course you'd pay more upfront, but then your heating bills would be practically zero. In warmer climates it would be much simpler, you could probably get away without burying it.
This is essentially what a ground source heat pump system is. Except instead of a sealed water tank you just make a tall hole that fills with water and the sun will warm it for you during the summer automatically.
1800 kWh is very little. We use around 12000 kWh and our neighbours' new house uses around 8000 kWh annually and most of that is heating. I'm not sure how many houses can hit 1800.
A ground source heat pump (also geothermal heat pump) is a heating/cooling system for buildings that use a type of heat pump to transfer heat to or from the ground, taking advantage of the relative constancy of temperatures of the earth through the seasons.
https://en.wikipedia.org/wiki/Ground_source_heat_pump
You can also recharge your geothermal well or ground heat collection field by heating the outgoing thermal collection liquid with either cheap electricity (rooftop solar?) or direct solar heat collection. I think this will be a growing thing as the earliest mainstream ground source heat wells start to be a few decades old. Many of them are sized so that they don't fully recover during the summer, so the heat output slowly drops.
Heath energy required != electricity requirement.
A modern house in Finland needs around 15-24kWh a year of heat energy if it's well insulated. On the higher end for big + northern houses, and less if you're smaller and further south.
Some get this energy by burning wood, others with heat pumps, and some with direct electricity.
24kWh is 1kW drawn continuously for 24hrs.
That can’t possibly heat any home for an entire year.
I think they mean per square meter of living space.
I think MWh is meant, otherwise it makes no sense
My 90sqm bungalow in the U.K. uses about 15MWh a year for heating - 1500 litres of oil, almost all in winter. Peak load is about 2.5kW over a day (60kWh)
24k kWh
it does! With a heat pump and insulation.
I think you are off by about 3 orders of magnitude as my Austrian flat need about 7MWh a year for heating and 3MWh of electricity. I could generate 24kWh per year on an indoor bicycle.
I can't find the link now, but there was an episode of Grand Designs here in the UK (a show detailing private individuals developing interesting or unusual homes) where the owner was building a passively heated house based on an idea by his architect father.
The ground beneath the footprint of the house was insulated around the sides to a depth of about 2m, effectively extending the thermal mass of the house into the ground. After construction, it took about 2 years (IIRC) to warm to a stable level, but thereafter required little to no energy to stay at a comfortable temperature year round.
I remember that one, but also can't find a link. Wasn't the heat from the people living there, and from appliances etc. enough to keep it at a comfortable temperature?
I love ideas like this.
I'd like to see the stats on temperature levels over a lifetime.
I'd be interested to see the ventilation system.
50m³ is huge. IMO that would be an engineering challenge that would probably impact the sability of the foundation if not done right.
Ground source heat pumps are expensive because of the buried piping, I imagine this would be even more costly.
> I've always wondered why we don't build homes with a buried tank of water used as heat storage. In the summer it can be heated with solar thermal to around 90c, and in the winter heat can be drawn out and go through radiators or underfloor heating, with a mixer valve. You just need a few pumps and valves, not even a heat pump is needed.
Because building houses is already expensive, and that would add significant amount, pushing it into "can't afford it in the first place". And zero ability to realistically service it means anything going wrong might make whole investment moot.
On top of that, any investment like that competes with "why not just put the money into low risk fund"
> 1800kWh per year
now factor in losses for months now factor the fact the energy you're using for heating is one you're not using for... energy or selling
also is that heat or energy ? Because if that's "what power heat pump used", multiply that by 3-4
It's just... expensive to do it like this. Expensive enough that most people that could did the math and it wasn't mathing
I'm not sure if the 1800kWh is correct here. I'm guessing it's one of these two:
- You're talking about what heat pumps use in electricity. However, the system would store heat. If a heat pump uses 1 kWh to get 3 kWh of heat into the house, a heat based storage system needs to store the 3 kWh.
- You're confusing gas & electricity. 1800 m3 in gas would be about correct. However, that's about 9,5 kwh per m3 in heat.
There are interesting heat storage methods though, there is a long term basalt heat storage system in 'Ecodorp Boekel' in The Netherlands. It uses solar to heat during the summer and heats the homes with that in winter.
Due to size though, it only really works in 'collective' communities. The bigger the size, the more heat it can store per size.
Something like that was attempted south of Calgary, in Canada: https://en.wikipedia.org/wiki/Drake_Landing_Solar_Community
Sounds like it didn’t go so well: In 2020, the system started showing signs of deterioration resulting in significant maintenance issues. System components, knowledge, and technical expertise for repairs were becoming increasingly challenging to find. In response to system failures, the Drake Landing Solar Company added redundancies to the system to be sure that homes in the community were receiving heat… In 2024, a decommissioning process for the Drake Landing Solar Community began, where the majority of the 52 homes were converted to natural gas-fired furnaces.
Nowadays, solar thermal collectors are completely obsolete except in very niche applications. Solar PV is so cheap that it’s literally cheaper (not to mention much less maintenance) to wire a bunch of PV panels to a resistance hot water heater than it is to directly heat the water with thermal collectors!
And if you use resistance heaters, you can get to much higher temperature with practical systems.
> I've always wondered why we don't build homes with a buried tank of water used as heat storage
Skip the tank completely. Use the ground directly. This is what geothermal heating does.
Drill a deep hole and drop tubes into it. Use a heat pump to pump heat into or out of the ground. There is so much easily accessible thermal mass in a borehole that you don’t need to deal with a giant underground water tank
Its kind of done. Active heating systems often have the intake air go through the foundation so it heats up in summer and cools down in winter reducing both heating and cooling costs.
Billions, mostly.
Not in the rock that geothermal can access. That rock is recharged by heat flow from below on a shorter timescale than that (but much longer than geothermal would extract the heat.)
As I understand it, most of the heat that was deposited by radioactive decay in the crust three billion years is still in the crust, not having had time to conduct its way to the surface, and most of heat deposited in the crust even today is from radioactive decay in rocks in the crust itself. But https://en.wikipedia.org/wiki/Geothermal_gradient#Heat_sourc... says that's wrong: "An estimated 45 to 90 percent of the heat escaping from Earth originates from radioactive decay of elements, mainly located in the mantle."
https://en.wikipedia.org/wiki/Geothermal_energy#Resources says 20% of the Earth's internal heat content is residual heat from planetary accretion 4.5 billion years ago, but of course that's mostly not in the crust. It also says, "the conductive heat flux averages 0.1MW/km²."
At the given thermal gradient of about 28°/km, a nominal thermal conductivity of 3.3W/m/K for granite (https://www.sciencedirect.com/science/article/abs/pii/S00137...), we can derive a heat flow rate, which works out to 0.09 MW/km², in good agreement with the Wikipedia number. By dividing by a nominal specific heat of 0.7J/g/K and some density estimate like 2.4g/cc, can we get a speed in meters per second? The units don't quite work out; the specific heat times the density gives us 1.7MJ/m³/K.
So I guess I don't know how I came to my conclusion, so maybe it's wrong. How did you come to yours?
Just as important here: The higher the temperature of the storage medium, the higher the fundamental limit to how much electric energy you can recover.
Put differently: If you used the same amount of energy to heat one bucket of sand by 200C (A) or two bucket of sands by 100C (B), you would be able to recover more electric energy from case A because of the fundamental Carnot Limit. This is why sand is a good storage medium (as opposed to e.g. water), and why some solar power systems work with molten salts. Also why steam-based power plants need to operate at high pressure to be able to obtain high-temperature steam.
I'm pretty sure this is intended to store and produce heat anyway. They aren't going to be using this for generating electricity.
Yeah but if you transfer the energy as heat then you will end up with elongated structures (pipes).
You speak theoretically but metropolitan areas in these countries all have those pipes in place and in use for the better part of a century.
Using heat for heating has many redeeming qualities. Heat is high entropy and it is not a good idea to "waste" low entropy energy to create high entropy energy. Many industrial processes run on heat and waste heat is generated everywhere. The systems are also cheap to run once in place.
That's a real issue, but this is for a district heating system which already exists and already faces this issue. And yet the district heating system is presumably practical.
Changing to a different central source of heating (i.e. storage) seems orthogonal.
Is that a problem? Pipes are not technically complicated. Is there something else I'm missing?
Larger storage structures are easier to (thermally) insulate. Because geometry.
But going with larger structures probably means aggregation (fewer of them are built, and further apart). Assuming homes to be heated are staying where they are, that requires longer pipes. Which are harder to insulate. Because geometry.
I can't help but wonder how the efficiency compares to generating electricity, running that over wires, and having that run heat pumps.
The conversion to electricity loses energy, but I assume the loss is negligible in transmission, and then modern heat pumps themselves are much more efficient.
And the average high and low in February in 26°F and 14°F according to Google, while modern heat pumps are more energy-efficient than resistive heating above around 0°F. So even around 14–26°F, the coefficient of performance should still be 2–3.
> heat pumps themselves are much more efficient.
For electricity-to-heat conversion, heap pumps are indeed much more efficient relative to resistive heating, yes. About 4 times more efficient.
In absolute terms, though - that is still only 50% of "Carnot cycle" efficiency.
https://en.wikipedia.org/wiki/Coefficient_of_performance
Similarly, heat-to-electricity conversion is about 50% efficient in best case:
https://en.wikipedia.org/wiki/Thermal_efficiency
So, in your scenario (heat->electricity conversion, then transmission, then electricity->heat conversion), overall efficiency is going to be 50% * 50% = 25%, assuming no transmission losses and state-of-art conversion on both ends.
25% efficiency (a.k.a. 75% losses) is pretty generous budget to work with. I guess one can cover a small town or a city's district with heat pipes and come on top in terms of efficiency.
We've got lots of heating districts around the world to use as examples. They only make sense in really dense areas. The thermal losses and expense of maintaining them make them economically impractical for most areas other than a few core districts in urban centers... Unless you have an excess of energy that you can't sell on the grid.
Geothermal heat is also not that functional in cities, you'd need so many wells so close together that you'd most likely cool down the ground enough in winter so your efficiency tanks.
I don't understand, what am I missing? The heat pump increases efficiency by having COP 2-4 right? Assuming air to air and being in, say, Denmark.
Heat (above 100C, say, burning garbage) to electricity: 50% (theoretical best case)
Electricity to heat (around 40C): 200%-400%
Net win?
The surplus energy comes from air or ground temperatures..
Yes you cannot heat back to the temperature you started with but for underfloor heating 40C is plenty. And you can get COP 2 up to shower water of 60C as well.
Yes, this is exactly why I asked. You need to include the COP in the calculations.
If the heat is stored at high temperature, but the demand (for heating buildings, say) is at lower temperature, it could make sense to generate power, then use that power to drive heat pumps. You could end up with more useful heat energy than you started with, possibly even if you didn't use the waste heat from the initial power generation cycle.
Alternately, if you are going to deliver the heat at low temperature to a district heating system, you might as use a topping cycle to extract some of the stored energy as work and use the waste heat, rather than taking the second law loss of just directly downgrading the high temperature heat to lower temperature.
High temperature storage increases the energy stored per unit of storage mass. If the heating is resistive, you might as well store at as high a temperature as is practical.
Gas-fired heat pumps have been investigated for heating buildings; they'd have a COP > 1.
I am interested if there are any cheap small scale external combustion engines available (steam? stirling? ORC?)
It can be anything between easy and impossible depending on the temperature difference. 200 C steam is easy with a commercially available turbine, but 50 C is really hard. There are things like Sterling engines that can capture waste heat but they've never really been commercially viable.
There's no way around it: We have to respect entropy.
I think the big cost difference is the geothermal generators to convert the heat back into electricity. More of a cost issue versus efficiency.
Existing district heating systems can be large.
I live in Denmark the powerplant that heats my home is about 30km away. There are old powerplants in between that can be powered in an emergency.
Yes, building district heating systems that large is difficult and expensive, it wasn't built yesterday, more like 50 years of policies.
Pipes are competing with wires, which are much less technically complicated than pipes.
Yes and a freezer that is only a bit larger, taller or deeper has a lot more liters of storage. Not just because it's in 3D but also because a smaller freezer still needs big sides. So, a lot more liters but only a tiny bit more energy consumption.
ps: living in an area with a high price per square meter goes against this strategy unless you manage to share a freezer
From the article:
> [250MWh] held in a container 14m high and 15m wide
According to Gemini 3.0 Pro, lifepo4 is 1.5-3.5x more dense than this, which isn't bad. 250MWh is a lot of capacity for such a small land footprint. At 2MW it can power ~2000 homes for ~5 days while taking up the land footprint of ~1 home.
What's the price? And how does the price scale with capacity?
The problem seems to be heat quality - they don’t get electricity back, it’s only good for heating. (Which admittedly makes perfect sense in the winter near the North Pole.)
The issue we have in Finland is the assymetric electricity usage between winter and summer. This is driven by the need for heating.
In the past, district heating systems burned coal. Now that's out the window we haven't got enough to burn. We do burn waste products from forestry, trash and the like but there's not enough to go around before you start felling trees en-mass just to heat a city.
A lot of municipalities in Finland are now starting to play with thermal storage. There's this sand battery, but there's even more hot water storage being built and has been built.
In the medium term, winter electricity production and consumption is starting to become a bit of a risk for us.
It doesn't just make sense in the very far north, it makes sense just about anywhere that you'd have many people living close together (i.e. even a village).
Most homes don't need to have their own electricity generators, their own sewage treatment systems, or their own water wells, they hook into utility infrastructure.
In a lot of european towns and cities, heat is also a utility you can hook into, e.g. my apartment has no heating infrastructure in it, we just get all of our heat through a pipe connected to a nearby heat reservoir that's primarily loaded with waste heat from a gas power turbine. Within the next couple years though, the heat from gas power will be supplemented with the biggest heat pump in the world though [1]
It's not just a city thing though, I have friends who live in a village of 300 people in the Alps and they also have a utility district heating system in the village.
[1] https://www.man-es.com/company/press-releases/press-details/...
> near the North Pole.
Finland is not near the North Pole. Lahti is at 61°, right in the middle between Greece and the North Pole.
But yes, heating needs are higher than in most European or North American populated areas.
I was interested in trying to make a DIY thermal battery as a hobby experiment. Other than using thermal energy directly, I couldn't find a way to effectively convert the heat energy to electrical energy.
Peltier modules can be used to generate electricity, but they are crazy inefficient.
An efficient steam turbine is largely inaccessible to hobbiests and I am scared of steam/pressure. Though I did look at repurposing a car turbo for this purpose. There were additional issues with regulating the amount of heat you wanted to extract (load matching) and recycling waste heat.
I wondered if it was possible to use a Sterling engine, but you can't buy anything other than very small toys online and I don't have the facilities to machine my own.
Haha, would love to get something working, but I suppose I'm not smart enough to figure out an effective way to get that heat back out as usable/controlled electricity.
The answer in almost all electrical production boils down to spinning a turbine with steam (or wind). Nuclear does it, all the fossil fuels do it and ultimately heat batteries do it too. The alternative is photovoltaic or directly nuclear to electron production and then storage with chemical batteries or massive capacitors.
Most of our electrical production is based on a solution found several hundred years ago, we just made it really big and worked out how to control the heating and pressure of the steam well.
Non-steam turbines have been operated (e.g. https://en.wikipedia.org/wiki/Mercury_vapour_turbine), but… steam is just so much easier to work with.
Come on, mercury vapour sounds like sooooo much fun! Where's your sense of adventure?
/s
You missed thermoelectric generators that uses the Seebeck effect to generate a current between two temperature differentials. It's terribly inefficient, unfortunately.
> An efficient steam turbine is largely inaccessible to hobbiests and I am scared of steam/pressure.
Thermal electricity generation really benefits from scale and extremes. The Carnot efficiency is proportional to the temperature differential between hot and cold. Even so-called "low quality" heat from a standard nuclear rector design is far hotter than anybody should deal with at home and it only gets ~1/3 efficiency. And dealing with small turbines is really inefficient too.
This is where batteries and solar really shine. They scale so well, and are extremely economical and electrically efficient.
Heat storage works well when you get beyond the scale of individual homes, but it's hard to make it work. I'd love to see something related to heat pumps in the future for homes, but district heating, such as could be accomplished by converting natural gas systems to heat delivery, are probably required for it to make sense.
Yeah, sadly, it seems almost impossible to get anything higher than 30% efficiency (theoretically with a Stirling engine, if you can find one, haha) out of a thermal battery without extreme pressures and temperatures.
Back-of-the-napkin math felt promising. A 1kg block of sand heated to 500 degrees Celsius should contain about 100Wh of electricity. Scaling that capacity up is easy, as it's just about adding sand or temperature (+ an effective method of transporting heat across the sand - maybe sand + used motor oil?).
Assuming 80% efficiency, tariff arbitrage (buy electricity during off-peak hours and use it during high-price hours) would pay off very quickly. In my area (Australia) it would be a matter of months - but the low real-world efficiency and lack of parts make it impossible.
It could work for heating during winter, though perhaps an AC/heatpump with the condenser a couple metres underground would be better value for money.
Heat storage can work for individual homes on the shorter scale. If you heat your home with in-floor heating (lower temperature requirements) you can have ~1-2m3 buffer tank that you heat up during the night and then use the stored heat during the day to heat your home. Works very well.
This project is for district heating, not producing electricity.
In general it is true that low-grade heat is difficult to convert to electricity, and there isn't any existing mass-market device that does it. You'll have to make your own, which involves learning to machine and responding to your perfectly reasonable fear of steam and pressure with proven safety measures.
Every couple of years I look around to see if anyone is selling sterling cycle engines in the 5-10 hp range, I always find a couple neat projects but nowhere can you just buy an engine.
I assume that because there is no current market for small sterling generators nobody wants invest in tooling to make one and because there are no small sterling generators there is no market for them.
In the articles case the end use of energy is household heating, so there is no need to convert back to electricity. The whole beauty of thermal energy storage that the end use of energy in many use cases is.. heat: heating buildings, cooking, industrial heating (from food processing to iron smelting), producing steam, etc.
If you need to use heating in a cold climate, you could use your stored energy to heat the radiator of a heat pump, which would then be drastically more efficient than using normal air on the radiator.
There's a video of people doing this on YouTube. They use the ground as their heat source. https://youtu.be/s-41UF02vrU
https://en.wikipedia.org/wiki/Thermoelectric_generator
Seebeck generator, generally. Peltier goes the opposite way. But basically the same thing.
If your hot source is really hot, thermophotovoltaic (https://en.wikipedia.org/wiki/Thermophotovoltaic_energy_conv...) makes sense and can offer much better efficiency...
LFP is so cheap that small-scale thermal battery makes not sense for electricity generation. Even in big scale (like OP) it mostly makes sense for heat, e.g. district heating systems, industry process heat, etc.
In a cold climate, I would expect burying it to use the ground as a natural insulator. Why was an above ground design chosen?
Specifically, does the need for heavy insulation and the active heating of the sand make the ground a less effective or even problematic insulator? Could excavating and building a below-ground foundation for a high-temperature device like this be more complex and expensive than an above-ground silo? How would permafrost conditions affect this design?
> Why was an above ground design chosen?
Because digging is expensive and there's plenty of land. More efficient to use the budget to build a bigger structure than to build a smaller one and dig down. Bigger structure also gives you better insulation (surface area compared to volume decreases non-linearly with increased volume).
Also, digging in sand is easy. But blowing up granite isn't. The Ice age stripped a way a lot of soil in Finland.
We’re pretty accustomed to building underground in Finland. You can find all sorts of English-language articles about it.
https://abcnews.go.com/International/helsinkis-underground-c...
Why do so many people do "why didn't you..." As if the engineers who designed this didn't have 1002 alternatives and went with this one for reasons of budget, politics, prior knowledge, IPR costs, skills, religious beliefs, or a million other reasons.
Why did we go to the moon when we have perfectly good vacuum chambers here at home.
The implied "my way is better" in these responses is usually the bad take on "what made this better than my way" as a question which nobody really can answer unless the OP is the engineer.
"Why does Finland not deploy ubiquitous small nuclear reactors every 25 meters and make a heated road to the north you can drive over as well as get power from if you have a power adapter for finnish plugs"
Interesting. Does anyone know what source of electricity is going to be used for this ? Probably solar but it might be also useful with coal plants or wind farms that produce even when there is not enough demand. How are they moving the heat ?
Wind in practice. There's only few hours of sunlight in the winter during the day. There has been a surge of electric boiler buildup by district heating companies in the last few years to exploit the periods of high wind and resulting very low electricity prices.
Heat is transferred using disctrict heating networks where 65-120 C water is circulated.
It's a heat battery for district heating. Could be other sources than electricity, e.g. municipal garbage incineration plant.
No, these generally use excess power during the night and windy days to store heat.
There's not that much CHP production that there'd be excess, plus they can adjust those plants well enough that there's no unnecessary burning going on.
There's water based heat batteries (aka thermal storage caverns) that are supplied with district heat in use in other places, but this is not one of them. The article says "Polar Night Energy’s technology works by heating a sand or a similar solid material using electricity"
See my other comment about Nordic power balancing.
Most likely not solar since there’s almost no solar during the winter months. Sun comes up at 0900 and goes down at 1500 in the south. In the north it’s worse.
It's currently noon in Finland and solar accounts for 6 MW in the grid. That's about 0.05% of the total production. Nuclear is 3863 MW (~31%) and wind is 6281 MW (~50%).
What might be plentiful is wind, especially during the nights.
Natural gas and wood chips,
> "The installation will supply heat to the Vääksy district heating network and is expected to lower fossil-based emissions by approximately 60% annually, primarily through an estimated 80% reduction in natural gas consumption and reduced reliance on wood chips."
https://www.pv-magazine.com/2025/11/25/finlands-polar-night-...
Those are the energy sources they're replacing with this tech - according to <https://reneweconomy.com.au/new-worlds-largest-sand-battery-...> it's surplus energy from renewables that will 'charge' the battery (so likely wind, hydro and solar that is produced but surplus to the grid's requirements)
A website called energy-storage dot news should not be mixing up energy and power
I was surprised too at the 2nd sentence: "The project will have a heating power of 2MW and a thermal energy storage (TES) capacity of 250MW..."
and how a news outlet about energy could get such a fundamental unit wrong.
But given that later in the article it does revert to correct units (and the numbers are plausibly proportional), I assume it's just a typo. Strange that it hasn't been corrected even now.
"...It follows Polar Night Energy completing and putting a 1MW/100MWh Sand Battery TES project into commercial operations this summer..."
These are interesting, but the cost per kWh of storage capacity is still probably too high for true seasonal storage. Short term storage runs into competition with batteries.
I point again to Standard Thermal for an idea tailored to true seasonal storage. I wait for more news from them, particularly on their very low cost resistive heater technology.
https://www.orcasciences.com/articles/standard-thermal
Doesn't need to be seasonal, we have enough energy in general to go through winter. This is to help through week long cold snaps, when Finland is short on energy. Week-long storage is still eyewateringly expensive with chemical batteries.
Also the capex from sand battery goes to (mostly) local construction, while when buying chemical batteries all the money goes to china.
But thermal storage doesn’t wear out, unlike batteries, right? So less future maintenance. Plus there is no danger of battery puncture.
More directly this is a very cold area. Enough it might effect battery storage enough to be a real problem.
I'm not sure why you think not wearing out would necessarily make up for the capex being too high. Interest rates aren't zero.
Not wearing out increases the time frame across which you can amortise the costs.
If option A costs $100,000/unit and needs to be replaced every 10 years, while option B costs $300,000/unit but lasts 50 years before replacement, option B is still cheaper in the long run, even factoring in interest rates.
(You can substitute "time until replacement" in the above with "time until maintenance costs exceed the original capex", and the logic remains the same.)
It's probably my ignorance about this sector, but I do find it impressive that they are getting that much storage capacity in a small area:
> "This latest project will use locally available natural sand, held in a container 14m high and 15m wide."
AI says this volume will hold about 4000 tonnes of sand. Hence the high capacity.
The big question is how much it will cost. For comparison I believe there is a heat battery in Germany using (atmospheric pressure) liquid water (98 C), 50M EUR for perhaps 20x the thermal storage capacity (versus 20 C water).
The use of sand, presumably heated to a much higher temperature than the boiling point of water, seems overkill for district heating (unless peak heat demand requires flow temperatures above 100 C). But it does reduce the volume of sand required, so the size of the storage system.
The cost is a function of the size and mass. So, more heat capacity and less mass means lower cost per mwh.
These things are extremely simple and fairly efficient. It's resistive heating (wires and spools) of a thermal mass (sand/stone) in some kind of container (a simple silo) with a lot of insulation and some pipes to heat up water. Higher temperatures mean getting the heat out is easier and that the battery will work for longer. Basically until the temperature drops below the required temperature.
> So, more heat capacity and less mass means lower cost per mwh.
Can you compare different technologies with these scaling laws? Also what are the limits of these approximations (e.g. taking temperatures to extremes tends to run into maintenance problems).
In this case the sand battery delivers 400 C steam from 600 C sand [0], via some heat exchange fluid (solar salt?) that flows next to the sand. Going through heating/cooling cycles can cause material issues, especially for larger temperature differences.
[0] https://polarnightenergy.com/sand-battery/
Required temperature is 65 to 115... If you are already above those you only need simpler and cheaper heat exchanger instead of more complex heatpump.
>The use of sand, presumably heated to a much higher temperature than the boiling point of water
600°C according to their website.
would someone give an ELI5 on how a sand battery works? Is it just purely thermal mass, just with tons of sand?
There's pipework for circulating air inside it when they want to charge/discharge it, but yes, essentially it's mostly tons of sand.
They have resistors for charging it with electricity (resistors heat the air, air is circulated in the pipes which heats the sand) when the electricity price is cheap, and then for discharging they have a air-water heat exchanger so they can pump the heat energy into the district heating network.
Why do they use air for this instead of water?
Likely a combination of practicality, and the importance of airflow throughout the sand in order to heat it and pull from it effectively.
Also, water's specific heat capacity is 4.186 J/g°C, while air's is approximately 1.005 J/g°C. It would take much more energy to heat up water than it would to heat up air.
Also, water boils at 100 degrees, and they store it in the sand at 600 degrees.
You use electricity (ideally cheap solar/wind) to heat air. That hot air circulates through a silo full of sand. The sand holds the heat for months. Later the heat is drawn out and used for buildings or industrial processes.
I like how sand batteries are the equivalent of sleeping on the ashes of your fire
Those of us in the UK will recognise this as a giant "Economy 7 Night storage heater".
I do kind of wonder will those come back, with a slightly smarter heuristic for turning on than "it is night". They're inefficient next to a heat pump, but vastly cheaper to make and install, so with a smarter grid, they may be an appropriate sink for excess solar/wind in times of overproduction.
This is great news! Congrats for this fantastic progress.
I never see sand battery before
between this and salt battery which one is the future???
AFAIK sandbattery is simpler (for district heating) and thus cheaper.
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There wasn't much about the energy equation there. And since it's just conversation with Gemini just pasted here, I'm not sure how much to trust it and it just feels lazy and disjointed.
EU is going to have to either
- embrace nuclear
- embrace North Africa, admitting them as member states, and doing massive solar there, and doing massive grid expansion to carry it north. And then in top of that, will their way to sufficient storage like the rest of us.
We'll see what they choose :D
EU does have trouble with solar seasonality, but wind is seasonally anti-correlated with solar, and the geospatial correlation between different wind turbines drops off more than linearly with distance, and the EU covers a very large land mass as-is. You can also over-build solar inside Europe to have reasonable collection during winter.
I also see no reason to admit North African states into the EU before an agreement can be reached about transporting solar. The geopolitical risks have always been about other states severing the link during a conflict with you, and less about the parties to the deal reneging. So whether Morocco or Algeria is part of the EU is quite immaterial to the risk profile.
This kind of thing really does need simulation modelling to be reasoned about properly. The one thing I am confident in saying is that these single sentence just-so stories about what is and isn't a good idea are going to be wrong, because the fundamental principle is statistical diversification, which needs to be approached through simulation rather than through words.
Here's your modeling site:
https://model.energy/
It's helpful to have two flavors of storage; one short term and efficient (batteries), one long term with low capex (hydrogen, thermal). The last is the most undeveloped but there are promising ideas.
This is really interesting.
I put some numbers into this, and the required power for long term storage is significantly lower than I'd have expected.
This was giving me for Germany (assuming 80GW of constant demand) under 50GW of required hydrogen turbine power (35GW of gas turbines are already installed, but only a fraction H2 ready).
Overprovisioning (wind/solar) is suprisingly high, with 180GW of wind and 440GW of solar. Currently installed capacity for those is about 30% of that.
Short-term storage capacity is a really big gap though (the model suggests 750GWh, and currently there's <30GWh installed).
In conclusion: Under pessimistic simplifications, Germany is at about 30% progress toward fully renewable electricity (but battery capacity is lagging behind).
Assuming wind/solar buildout continues at rates comparable to the last decade, this would mean zero-emission electricity in ~35 years. Could be worse. But I'm personally bracing for 2-4°C of warming, and don't think european glaciers will survive the next century...
The amount of long term storage (and the duration) depends on the balance between wind and PV.
If wind and PV have similar levelized cost of energy (LCoE), then the solution will use the lack of correlation between the two to avoid much storage. In this case, long term storage is over period of the variability of wind, which might be weeks.
But if PV is significantly cheaper than wind -- and this is where trends are going -- then long term storage becomes more for seasonal leveling, at least at high latitudes.
There's still a large place for short term storage, and economics is still strongly affected by the cost of that storage. So it's great news batteries have become so cheap to produce.
V2G can provide the short-term capacity. If one allocates e.g. 40 kWh from their battery to V2G, each million electric cars can add 40GWh of grid tied battery storage. If you pay people fairly, it will happen. There are more than 4 million electric cars in the EU already...
In Austria at least you cannot even charge your car with properly priced electricity unless you have your own outlet. At some chargers it is more expensive to charge through the night (because of blocking fees over 4-5h) even though we basically always have the lowest prices then.
Why do you say "embrace nuclear" when the EU has substantial existing and planned nuclear plants? (Current gen is something like 24% nuclear in EU, 20% in wider Europe, 18% USA, 4.4% China)
And anyway, alongside that world leading nuclear already in existence why wouldn't they just install lots of cheap solar and wind, and heat pumps and EVs and reduce their imports of energy from their current high levels (about .6 Trillion euros in 2022, down to .35 in 2024 though that seems mostly a change in price, volume has declined only slightly)
Embrace nuclear would be continuing the existing recent trend of the Germans stopping talking down to the French, and also figuring out how to build new ones in a timely matter.
Solar is pretty terrible outside of Spain, and even there the latitude is not great.
The EU has plenty of solar and wind resources.
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Finland's current energy equation according to Google Gemini:
Gemini: ... In summary, Finland imports waste (mainly as pre-processed fuel) to feed its modern waste-to-energy plants, which are a key part of its heating and energy strategy, especially as domestic residual waste volumes decrease due to better recycling and as a replacement for former Russian renewable fuel imports. Gemini: ... This processing turns smelly, inconsistent "garbage" into a stable, high-quality, non-hazardous secondary fuel that is compliant with strict EU waste shipment and energy production regulations. The whole point of the import is to fuel power plants efficiently, which requires this specific, processed product. Gemini: ... Sometimes .... Gemini: ... It is clear that the environmental integrity and quality of life for residents of Loviisa have been compromised by the need to fuel Finland's waste-to-energy capacity with large, sometimes substandard, imports. etc etc.===
Short summary: The Pro-Russian Green "Pedophile"-Party destroyed the existing energy infrastructure which ran on coal from Poland etc. A new system was built to use "renewable" Russian gas and Russian wood industry leftovers.
The situation is desperate; any shit from anywhere at any cost is better than using local renewable biomass, such as peat.
Finland has enormous amounts of peat, which is worth more than Norway's oil reserves.
The comment is slightly incoherent in it's argumentation, but factually correct.
I think the point is the energy policies in some of the nordics are as arbitrary and politics driven as anywhere.
How this is directly related to the sand battery is not clear to me, but it does paint an accurate if partial picture of the milieu.
Pedophiles were insulted, I am sorry. Correct English expression is maybe "Baby Lovers"? I dont know.
Peat grows at about 1 mm per year, if it regrows at all at the location where you did the extraction.
Calling Green Party "Pro Russian" is ridiculous. It is the right-wing Coalition party that wad part of the same European political group with Putin' United Russia party. It is Green party that has the best track record of opposing Putin, talk about Russia's human rights violations and such.
Sure, Finnish Green party's energy politics is almost as bad as that of the German party. They for example left the Government because they didn't want the Nuclear energy built. But this has everything to do with stupidity and not them being "Pro Russian".
Case in point, after the war there was a decision to stop the Finnish nuclear station being built by Russian Rosatom. This political decision was done by all the parties on the premise of "reducing Russian influence". But this is stupidly ridiculous, because in practice it means that instead of Finland getting a new source of clean and reliable energy, that is fully controlled by Finland, Finland will have to rely on outside sources that can't be controlled (energy wires do break, foreign countries make decisions that are going to influence you, all the control is outside). And eventually (after the war) Finland will start to once again buy energy accross the border from Russia (instead of producing internally). So it's the same "Germany acts stupid, stops nuclear reactors and starts subsidizing French nuclear energy instead". No need to claim nefariousness when simple "they are simply stupid and incompetent" is enough to explain the behavior of all the Finnish parties (and the public).
"Pedophile" is equally non-sensical adhominem.
Hey @grok. Is there some grounds to call the Green Party a Pedophile Party?
Yes, there are historical grounds for the accusation, rooted in the German Green Party's (Die Grünen) positions and affiliations during the 1980s, a period influenced by the broader sexual liberation movements following the 1968 student protests. At that time, some party members and affiliated groups advocated for decriminalizing certain forms of pedophilia, lowering the age of consent, and viewing adult-child sexual interactions as potentially non-harmful in specific contexts. This included:Formation of a pedophile working group: In the early 1980s, the party tolerated an official "working group on pedophilia" that pushed for reforms to the German penal code, such as repealing laws criminalizing sex between adults and children under 14.
dw.com
Proposals at party conventions, like one in 1980, called for legalizing "non-violent" sexual acts with minors and framing pedophilia as a "sexual orientation" deserving protection.
spiegel.de
Key figures and statements: Prominent members, including future European Parliament leader Daniel Cohn-Bendit, made controversial remarks; in a 1982 TV appearance, he described playful sexual interactions with young children as an "erotic-manic game" based on his experiences as a kindergarten teacher.
dw.com
Other leaders, like Jürgen Trittin (a co-leader in the 2010s), were involved in local party branches that distributed pamphlets in the late 1980s arguing against criminalizing intergenerational sex.
spiegel.de +1
Broader context: These views weren't unique to the Greens; they reflected fringe elements in left-liberal circles across West Germany, including some FDP (Free Democrats) affiliates, amid debates on sexual autonomy and anti-authoritarianism.