The Precer Group has a pretty cool looking rig in their BioRacer concept, looks like something from the Halo video game. The Precer BioRacer has a 16HP electric motor powered by a 24 to 96 volt (100 to 400 amp hour) battery pack depending on configuration choices. The batteries are recharged by a Stirling engine that runs on wood pellets. When fully charged the BioRacer will run for up to 3 hours. Charging via the wood pellet powered Stirling motor takes 3 to 6 pounds of wood for about 10 miles of driving.