Bitcoin mining is doing exactly in some cases. E.g. there's a fair number of small, remote, hydroelectric plants whose construction and/or renovation were financed by Bitcoin mining, with the amount of mining declining over time as the community using them grew and ramped up consumption. Also in Canada there's a company working on making finance deals for small scale nuclear energy plants in the far north where the excess capacity will be temporarily used for Bitcoin mining while the community grows and/or industrial uses like mines ramp up production.

Re: the nuclear version, good chance none of it happens due to anti-nuclear sentiment of course. So far exactly zero of these small scale nuclear plants have been built.