Solarpunk technology

There's not enough focus on direct energy usage or storage in general. If you want thermal energy, collect and store thermal energy. If you want mechanical energy, use that directly (and I guess compressed air and hydraulic head count as mechanical energy storage).

What I think would be cool for an exercise bike is to just have a power takeoff of some sort. Lots of bikes use a flywheel already, but even if they didn't, but you could hook up a PTO to a flywheel or a charger so that in a pinch, you could charge your phone or whatever. Probably wouldn't want to use it if you had a better option, but nice to have in an emergency. Like those wind up flashlights.