@Helot - See Link above? That is a Sterling Motor Generator!

I didn't see that it was sterling, only diesel powered. Sterlings in their true sense should run on any heat source, but I assume these aren't cheap.

Really hard to justify it, as You can get an 800 Watt Two-Stroke Gasoline generator for $129, and the WhisperGen (800 Watt) is over $5000!!!

Sterling Cycle Engines are Relatively Weak, and also are slow. Because you can't run them at High RPM, The only way to make more power is to scale up. A 5KW Generator would be Physically HUGE. 50KW would be the size of a small office building.