> It seems like an ideal way to use excess energy in grid-tied solar setups where the energy company is not incentivized to buy excess power. Or for non-grid tied solar when your batteries are full.

The ideal way to use excess energy is to do almost anything else besides pointless proof-of-work computations (e.g some scientific distributed computing thing).

PoW isn’t useless, in fact, the energy cost of PoW is proportional to its demand.

Demand for a decentralised Ponzi scheme.

Explain to me how Bitcoin is a Ponzi scheme. There is no buy-in, there is no exit strategy, no dividends, no recruiting, there is nothing that makes it look like a pyramid scheme of any kind.

Maybe you mean that the early holders of Bitcoin have gained more wealth than later adopters or something? I'm not sure what you mean, actually. But that is just how a market works.

To its "demand" perhaps, but not it's value.

I love how in every HN thread about Bitcoin, someone says the coin currently trading above $30k has no value.

And who pray tell decides its value? The central planning committee?

As opposed to storing it?

Ideally you'd store it, but if your system is sized for the short days of winter, you may have excess energy in the summer that you cannot store once your batteries are full.

It seems to me like you’d be doing a lot more good if you used that excess power for something like carbon capture.

Bitcoin is surely pretty far down the list of useful applications of that excess power.