Diesel engines last longer, and are built for longer run times without service.
Fuel can be stored for much longer than Gasoline, and they cost considerably less
to run than Propane generators of the same size.
Why Military Generators?
Military generators are built to last. They are commercial grade units made for service
in all weather and environmental conditions without failure. Parts are common and readily available, as They are 100% made in the USA by companies like Onan/Cummins and John Deere.
Military units are made to run for long periods of time, weeks if necessary, without the need for service or maintenance. Military generators have superior voltage regulator systems not found on civilian generators, they are made to hold their voltage under heavy surges so sensitive equipment will not be damaged.
How do they compare to Standby Generators?
Standby generators are made for emergency use, not continuous use, because they run at higher speeds than Military Diesel generators, they generate more heat and require more maintenance and service intervals more often, generally after every power outage. Standby generators are rated in peak output, not real continuous output, so a generator rated for 20kw usually puts out 30% less on a continuous basis. Standby generators also have poor voltage regulation, causing them to drop voltage during motor starts like water pumps or furnaces, this not only causes the lights to dim, but it can harm appliances and sensitive electronics.
Propane generators consume lots of fuel, typically 6-10 gallons per hour, which can add up in a 24 hour power outage, it is also difficult to get refuelled. Diesel generators burn between 1/2 and 1 gallon per hour, which is a significant savings in a long power outage, and fuel is readily available when you need it.