I'm confused. Toyota gives the following specs for the 2004-2006 Prius: 110 hp Hybrid System Net Power 76 hp Gasoline Engine Power output 28 hp Traction battery power output Adding the power output from the gasoline engine and the traction battery, I get 104 hp. I thought that the net power the Hybrid system could produce would be less than or equal to the sum of the power from the engine plus the power from the battery, the two sources of power at any moment in time. (I say less than because of possible energy losses converting the battery power to mechanical energy and the possibility that the electric motors can't create 28 hp of mechanical energy from the battery when the engine is at high output and RPM.) Where is the Hybrid System Net Power coming from besides the gasoline engine and the traction battery? What is the source of that last 6 hp?