I saw that concept vehicle using those engines, they also had a generator and used nanosafe batteries, new batteries that can be charged in 10 mins and are eco friendly. There is also a new rotory engine out of Canada that is 6 inches in diameter and 6 inches long, and produces 42hp. They have a bigger version that produces 125hp. 42hp is more than enough for a 12kw generator. It will also run on any fuel you throw at it, the demo they have runs on diesel. It has 24 combustion events per rotation. "Calculated at 30% volume efficiency, compared to Wankel engine's 10% volume efficiency, compared to piston engine 7-8% volume efficiency." So it's also more fuel efficient. It's made by Regtech. http://regtech.com/ramcam.html