Long lasting low maintenance power sources?

Any know any low maintenance power sources?

I know solar panels can last for decades with very minimal maintenance such as cleaning.

Wind Turbines (specifically the huge ones) need a lot more, typically multiple checks per year.

Gas and diesel are quite common but aren’t too hard to fix, especially compared to windmills which needs climbing equipment

If you have a moving body of water nearby such as a river, stream, or creek you could make a small hydroelectric generator.

Lastly, there are human powered generators that are powered by peddles, hand cranks, giant hamster wheels, etc.