Backup Power Schemes said:

  Gas Turbine. Not very fuel-efficient, but much less routine maint
than Diesels. Also smaller.

variations: Propane fuel, Natural Gas

For those of you who have never had the pleasure of working with turbines,
they are not something you would want to be near humans who still want their
hearing. At about .5MW load, they have a marked similarity to a jet plane
taking off (no surprise.) Fine for out of the way places or low class
commercial areas, but probably not something that would want to be on a slab
in downtown San Jose or Palo Alto. Diesel is much quieter and easier to
muffle. But if you need a lot of power, natural gas turbines get really big,
and the odds of a turbine starting are better.

I like turbines, but almost never find a place to put them. (then again, I
still like MG sets.)