Both Cummings and Cat have power generation specialist at there dealerships. They have a wealth of knowledge if you are looking for one. Primarily 40 KW and up. I've worked with both on project's and have found that Cummins to be very flexible. At least in my area. I even had a Inn/restaurant customer in Avery, NY that was many miles from any power and had to make his own for years. Was a loved place for snowmobilers.