[thijson]

That might work in southern latitudes where the seasonal change in solar irradiation isn't much different. In the North, like in Canada, there's just not enough solar in the winter. We really need a way to store excess solar from the summer into the winter. Like on the scale of a 500 gallon propane tank.

[richjdsmith]

There is a finish company working on something that might fit this need: domestic sand batteries.

https://polarnightenergy.fi/sand-battery/

[metalmangler]

doing fine @ 45°north thank you, and know people living and making all of there income from solar even further north, with I might add equipment that is now outdated, but was much more expensive than what is availible now, which has almost doubled in efficiency, and is less than half the price, retail, with palet loads becoming bizarly cheap. When combined with a new build semi passive solar house, conventional heating systems can be omited entirely. There is a comming "solar divide" ....those who pay energy bills, and those that dont.

[euroderf]

Or a big deep hole full of pipes circulating water making dirt hot.