Hybrid
Hybrid vehicles produce an amount of emissions that is very close to, or sometimes lower than the levels that are recommended by the Environmental Protection Agency (EPA). This institution recommends an average emission of 5.5 metric tons of carbon dioxide for each regular passenger vehicle.
There are four types of hybrid engines, according to the technologies used: electric-petroleum system, Continuously outboard recharged electric vehicle (COREV), fluid power hybrid system and hybrid fuel. The most popular of these are the hybrid electric vehicles (HEV), which combine one or more electric power sources with an internal combustion engine.
Hybrid engines can depend on several different power sources, including hydrogen, solar power, wind, compressed air, rechargeable energy, liquid nitrogen, radio waves, human force and gasoline or diesel, amongst several other possibilities.
