Polar Night didn’t disclose the project’s cost, though the raw materials are cheap and the structure itself isn’t particularly complex. A much smaller prototype built a few years ago cost around $25 per kilowatt-hour of storage, the company estimated at the time. It’s likely the new version is cheaper. Lithium-ion batteries cost around $115 per kilowatt-hour.
“Economics look appealing”, but does not include costs.
This isn't really a battery. It's storing heat, to be used as-is for the towns centralized heating system. Thus you lose a lot less on the usage-side compared to if it was truly used as a battery, ie to generate electricity.
Here the "battery" is "charged" using electricity as input, however the electricity in Finland comes mostly from nuclear, wind or hydro[1], so should be able to utilize the renewable peaks well.
But yeah, I'd be surprised if this system would be as cost-effective if you didn't already have a centralized heating system to plug this into.
Interesting concept. Sort of a terribly written article. Things the author should have talked about:
1) comparison between life expectancy of a lithium ion battery vs a sand battery
2) environmental impact of lithium ion battery waste, vs sand battery.
3) ethics of lithium mining.
4) how lithium ion batteries perform poorly at colder temperatures (eg Finland)
There are a lot of strong arguments for these batteries the author seemed to just skip over, and instead focused on costs, which they don’t know the answer to.
If you try gauge the price from that cavern storage (estimated 200 million euros) then lets say it has some economies of scale, maybe this sand battery costs like 500k-1M euros.
If you just heat the storage on cheap hours and output at high prices. You could in theory cycle (24*365/2) hours at 1 MW so 4,4 GWh of energy per year. So how could be the project profitable?
In 10 year period with full utilization price differential would need to be 22.8 €/MWh to break even with 1M investment, then add operating costs, loan interest, etc. With more realistic utilization it would need to even higher.
Maybe you amortize costs over 20, 30 years. But its's even more uncertain what cost of electricity will be. I think it only makes sense if this storage allows them to electrify heat production replacing much more expensive current production.
lrasinen · 7m ago
22.8 €/MWh is just 2.28 c/kWh and that's a very low bar to clear.
Just yesterday we had 6 hours of negative prices, followed shortly after by one hour at 2.66 c/kWh and four more over 3 c. Friday had swings from 0.4 c to 13 c.
(All prices with VAT included)
And this is in summer when energy consumption is low, the swings will intensify when the heating season starts.
foxglacier · 54m ago
That and the downsides to the sand battery. We don't need more biased new stories trying to promote everything as miraculously pure-good. Environmental concerns hardly matter for utility energy generation because if it's not cheaper, it will will either completely fail or be a tax on everyone if the government mandates it.
The obvious problem is it can only really be used for heating, not electricity. But heating is still a fine use when available.
standardUser · 1h ago
This technology has been big in Australia for a while. I always wondered why it didn't catch on, given the relative rarity and expense of more 'advanced' battery materials. Now that lithium-ion seems to be taking over I wonder if these salt/sand thermal batteries will have a role.
Quarrel · 31s ago
is it actually "big" in Aus?
I know MGA Thermal have a demo project that the gov funded, but is there anything in commercial use?
passwordoops · 1h ago
I love the idea behind heat batteries but... "Polar Night didn’t disclose the project’s cost"
So we're using Trust Me Bro accounting everywhere now?
Here the "battery" is "charged" using electricity as input, however the electricity in Finland comes mostly from nuclear, wind or hydro[1], so should be able to utilize the renewable peaks well.
But yeah, I'd be surprised if this system would be as cost-effective if you didn't already have a centralized heating system to plug this into.
[1]: https://stat.fi/en/statistics/salatuo
2) environmental impact of lithium ion battery waste, vs sand battery.
3) ethics of lithium mining.
4) how lithium ion batteries perform poorly at colder temperatures (eg Finland)
There are a lot of strong arguments for these batteries the author seemed to just skip over, and instead focused on costs, which they don’t know the answer to.
If you try gauge the price from that cavern storage (estimated 200 million euros) then lets say it has some economies of scale, maybe this sand battery costs like 500k-1M euros.
If you just heat the storage on cheap hours and output at high prices. You could in theory cycle (24*365/2) hours at 1 MW so 4,4 GWh of energy per year. So how could be the project profitable?
In 10 year period with full utilization price differential would need to be 22.8 €/MWh to break even with 1M investment, then add operating costs, loan interest, etc. With more realistic utilization it would need to even higher.
Maybe you amortize costs over 20, 30 years. But its's even more uncertain what cost of electricity will be. I think it only makes sense if this storage allows them to electrify heat production replacing much more expensive current production.
Just yesterday we had 6 hours of negative prices, followed shortly after by one hour at 2.66 c/kWh and four more over 3 c. Friday had swings from 0.4 c to 13 c.
(All prices with VAT included)
And this is in summer when energy consumption is low, the swings will intensify when the heating season starts.
The obvious problem is it can only really be used for heating, not electricity. But heating is still a fine use when available.
I know MGA Thermal have a demo project that the gov funded, but is there anything in commercial use?
So we're using Trust Me Bro accounting everywhere now?