retrolefty:
Doesn't matter, solar for 100 years is a no go. Lighting strike, vandals steals the panel or paints it black, etc. Same for wind generation. The whole assembly must be self contained and sealed up securely. He did state " time capsule " now didn't he?Lefty
Nuclear it is then.
Seriously now. Where will the device be situated? Can you guarantee that the building/bunker/mountain that will hold it will be there in 100 years?
I'm thinking some sort of thermoelectric device, hooked up to a water flow on one side and something that fluctuates in temperature on other. The batteries would need to be capable of sustaining the device for a few months (which is possible), and would be recharged during summer and winter when there is difference in water/something other temperature.