A diesel generator is a good choice, as it is often or continuously in use. A diesel is more fuel efficient than a gasoline generator, and it is less susceptible to wear and tear. A diesel generator has a longer life than a gasoline generator. Diesel generators 1500 rpm, the engines even have a life span up to 35000 hours! Diesel generating sets with sound proof enclosure and can also be very, very quiet. The current stage 3 diesel engines have much lower emissions levels than previous engines.