Finland warms up the world's largest sand battery, the economics look appealing
techcrunch.com
techcrunch.com
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.
But the "smaller prototype" is 8MWh. Their estimate of $25/kWh would make that $200k, and this 100MWh unit should scale to $2.5M but there have already received many times that in funding. Who knows.
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.
Alternatively: 6 hours with 45 €/MWh differential, 3 hours with 90 €/MWh differential or one hour with 270 €/MWh differential.
There are several days when some of these happen, but I don't think its every day for ten years straight. There are lots of days when price moves in tight range or even if there is some movement there isn't enough of it.
The simulation model assumes we're charging during the 12 cheapest hours, and discharging during the most expensive 12 h, and then calculated the average price differential per day. This is of course suboptimal, since the day-ahead prices are available.
The mean differential in the data is 56.5 €/MWh, and on 64% of the days the differential is over 22.8 €/MWh. 10%, 50% and 90% percentiles are 3, 54 and 119.
So at least during the winter time (when consumption is greatest) you'd expect to hit the price goal more often than not.
Adding the rest of the year up to now drops the mean to 52 €/MWh and the median down to 38 €/MWh. Still pretty good.
(As for cherry-picking the data: this year was easily available and didn't dig too hard for older data, but it was one of the mildest winters in recent years.)
The obvious problem is it can only really be used for heating, not electricity. But heating is still a fine use when available.
Fossil fuels appear cheap specifically because the benefits accumulate to the corporation extracting and selling them, while a substantial portion of the costs get unevenly distributed to random people who's homes get destroyed by hurricanes or wildfires as well as everyone having to run their air conditioners more.
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.
(2022) https://www.treehugger.com/viral-sand-battery-isnt-what-it-s...
The word has been used that way for a long time, so I'm not gonna stamp on my dictionary and insist we look at the etymology. But it does show how the word's usage has shifted, and a continued shift to call this thing a "heat battery" seems comprehensible.
My complaint was more that just "battery" implies storing electricity directly in common parlance these days, and the fact that the heat output is used directly is quite significant.
Had the headline called it a heat battery I would have had no complaints.
I can't quite see the niche that's left, and from their talk about possibly generating electricity from the stored heat, it seems they can't either.
Maybe as a buffer for continual industrial processes that are above heat pump reachable temps (which means above 200C these days)?
It would be good if this worked out at scale of course; i do like that this type of battery can be made with cheaper materials. It makes it so that utilities/gov't can make use of large economies of scale, and have the benefits of renewables benefit everyone, not just people able to afford a solar/lithium battery pack at their property.
But this heat storage is a single purpose device, where as a battery is multi-purpose (you could also run a washer, dryer, water heater etc). So you have to count the energy loss of a battery to heat, and compare it with the extra energy required to _also_ power those other devices.
It's quite a hard question to answer...
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?