It used to be nuclear, but in favor of enviromentalism, I converted it over to a new power source.
Inside the back of the truck is a big biofermentation tank (OK, it's a <i>still</i>). The chips get blown in there where they are enzymatically converted into ethyl alcohol. The vodka gets piped to the fuel tanks for the truck, and into a 5 gallon can for the chipper.
I get home at night with a full load of chips. In the morning, there is an empty chip bed, and my fuel tanks are full.
The nuclear version chipper had quite a bit more power (500 megatons more), but I had to go dump chips daily. It was a trade-off.