Eh? All my sites' backup generators are either Cat or Cummins diesels.
At the telco I worked at for 34 years, we used a myriad of diesel engs. Volvo, GM, deutz air cooled diesels, BMC ( made in the uk) and several other brands. Some had turbos, some didn't. Biggest one is 2 megawatt ( 2000 kva), and is a V16 diesel. Took 2 cranes to lift it in the middle of the night with 4 lanes of traffic blocked off at 3 AM. Several small gen sets ran on propane.
Other than the real small 3/5/10 kw gasoline portable units tossed into the back of a truck for use at small tiny sites, everything else was diesel.
The actual generators were made in Stamford Conn. Some of the bigger mobile units, towed behind a truck, were 50-100 kw, and could be switched to run either 240/120 single phase.......or 208/120 3 phase.
Diesel fuel will last for years... vs gasoline. Even then, diesel fuel eventually is required to be cleaned, called polishing. Its sucked out, and ran through an external cleaning process, then into a temp tank. Then when process is complete...pumped back in. Some of the diesel tanks were above ground, and some are below ground.... and all are double walled types, with a vapor detector between the 2 x tanks. Typ deal is to pump from the big tank, (9000/35,000 / 50,000 litre) ..to a small day tank, ( 185-250 litre) located next to the diesel eng itself.