> The net result: Pornainen fulfilled all of its municipal climate targets with a single installation. Oil use dropped 100 percent, emissions fell 70 percent, and woodchip combustion was cut by 60 percent. According to the Mayor of the Municipality of Pornainen, Antti Kuusela, the municipality now heats all its public buildings, including a new sports arena opening in September 2026, entirely through this district heating network.
https://interestingengineering.com/energy/sand-battery-polar...
>During the coldest, most expensive stretch, the wood chip boiler became the primary unit, and the sand battery supplemented it.
Remarkably: heat is pointed to as "wasted energy" when doing EROEI analysis and discounted, this is done to strengthen the case for Solar vs Gas.
Finland's energy mix is ~6% solar [1]... maybe it's not a larger portion of the grid supply because Finns realize it doesn't work in the winter?
And it's quite compact.
> And only covers heat.
Is that not useful?
Until battery tech gets (and maybe even after) it's a good idea to build some nuclear too.