The following Blinding Flash of the Obvious is a huge marketing opportunity for someone.

Typical emergency generators tend to have a voracious appetite for fuel because the run full speed even at low load. The Honda "inverter" generators can throttle back at low load but keep running.

Why not take it a step further and add a built-in battery and auto starter to an inverter generator? Now you have continuous "keep alive" power to your heating system, refrigerator and lighting circuits, and the engine kicks in when the load increases.