Easier to generate a fixed-frequency AC output. Diesel engines can run at a fixed RPM and adjust fueling to match load, where gasoline and natural gas need a n

Easier to generate a fixed-frequency AC output. Diesel engines can run at a fixed RPM and adjust fueling to match load, where gasoline and natural gas need a narrow AFR and have to vary rotation speed for power output. Maybe less of an issue these days as inverter/generators are more common, though I dunno if that's the case for the big generators.