
Other hybrid alternatives
Several new vehicle engine types seem technically possible at this time.
New engine types which require chemical-based fuels include the hydrogen-burning engine and the fuel cell-based vehicles. The hydrogen-burning engine takes compressed hydrogen, while fuel cell-based vehicles can use either compressed hydrogen or alternate chemicals like methanol. Because of an immature distribution infrastructure for compressed hydrogen and other alternates, these vehicles should be viewed only as concept cars not available on the market in the short to mid term.
The other major alternative category is vehicles incorporating an electric battery to drive their power delivery systems. There are several types:
BEV or CEV: Battery Electric Vehicles or City Electric Vehicles are the classic electric cars of pulp science fiction. These are purely electric cars using a battery to drive an electric motor. They need to be plugged into the electric grid to be charged, and have modest performance and low speed.
FPBEV: Full Performance Battery Electric Vehicles have greater performance than BEVs/CEVs. Their engineering optimizes power over range, better suited for freeways and cross-town travel. Tesla Motors makes the Tesla Roadster, a vehicle which epitomizes this segment.

PHEV: One example of the Plug-in Hybrid Vehicle concept, a variant of the General Motors Volt E-Flex concept, would operate as an electric car for perhaps 75km. Once the batteries deplete, a small gasoline engine fires up that runs a charging generator to sustain the charge, but not drive the wheels. Once the destination is reached, the PHEV can be plugged into an electric grid to get a full charge.
Of all these alternatives to the internal combustion engine, Hybrid Electric Vehicles (HEVs) are the first alternate drive technology to have been made commercially viable; the first commercially mass-produced and marketed hybrid automobile being the 1997 Toyota Prius. Hybrid technology adds efficiency by combining a gasoline engine with a high-torque electric motor and a battery, yielding better fuel efficiency and lower emissions.
Rigging up two under-the-hood power plants may sound wasteful, complicated and prone to failure, but the practice can actually provide up to 50 percent more miles per gallon while cutting pollution by a third in urban traffic.