However, that doesn't help during period when there is hardly any wind. It is not as if you can stop heating your house for a couple of weeks.
I'm curious have this will play out. On a bright summer day, there is plenty of solar power. So it make sense to do everything during the day. During winter, it is better to distribute the load and move load to the night. That requires quite a bit of signaling to get right.
Also wind is the main renewable in western europe, not solar.
Having no wind for weeks basically doesn't happen, at least in the north sea.
I have a Swedish fireplace. The firebox is very small, and the masonry is rather massive. The idea is for the masonry to soak up the heat, then slowly release it long after the fire dies down. Apparently the Swedes have used this design for centuries. I don't imagine the Swedes are such fools that they wouldn't notice for centuries that it doesn't work (it does!).
People also used to put rocks in the fireplace, then pull them out to put in their beds to warm them at night. This is just a primitive method of doing the same thing.
> The idea is to not only adjust supply to the demand, but to shape the demand to the supply.
> I am utterly astonished that this is never, ever discussed when talking about solutions to fluctuating supply. Having fixed electricity rates 24/7 is simply madness in today's electricity generation situation.
It might not be the same everywhere but in France and Belgium at least, it is very common to have two rates: peak and off-peak. A signal is sent by the provider to your electrical meter (basically 220V when off-peak, 0V when peak) that can pilot a switch that turns the hot water heater on only during off-peak hours.
Some electric heaters also work on that principle, they are filled with bricks and heat up during off-peak hours then release the stored heat later, when it is needed. That's your "battery consisting of a pile of rock". However, I have lived with those things and it doesn't work at all because storing heat in anything else than water just doesn't work well. Basically at the end of the day, when you come back from work and need the heat that was stored during the night, it's already gone (and totally wasted as the house was empty). The most modern designs don't work much better. I think these only still exist because the idea seems good enough to convince people to buy them, but it's not actually technically feasible.
Anyway, everything you say is already possible in western Europe, and already done (except for HVAC, but that's mostly because HVAC in private homes isn't very common in the first place). What could be improved is to have more dynamic off-peak hours, but that's not a technical problem, everything would already work as is.