The Hybrid is designed to run primarily on Gasoline, such as starting from a stop or running up a steep hill, using the electric motor as an assistant to the gasoline engine.The engine will only run on Electric mode in the 2006 and later models and then only when the conditions are just right.The Hybrid WILL consume gasoline only in much smaller amounts then a full gas engine.The Engine on the 2006 and later models is 110 HP with a 15 HP electric engine.Previous models have a 93hp gasoline engine with a 15 hp electric engine.These electric engines are designed to give you a boost when the Gasoline engine needs some help but not at the expense of using more gasoline.For the everyday user these engines should save between 10% and 15% of your average fuel bill.Hope this is helpful