In addition, like CNG it prolongs engine life. This fuel is extremely cheap, making it quite an attractive alternative. The permanent solutions for the future lie in electric and hybrid electric vehicles. True electric vehicles store energy in battery form exclusively. Parallel hybrid electrics, include both electric and petroleum drive units.
Series hybrids utilize a small combustion engine in order to power an electric drive unit.
For the commuter, the true electric vehicle is practical today. This car is essentially pollution free, the cleanest of all the alternatives. Parallel vehicles, two of which should be available in 1998, seem to offer the best of both worlds. An electric engine operates when the vehicle is moving at low speeds, avoiding idling, the most polluting time for an internal combustion engine. The combustion engine does not start until the vehicle is under heavy acceleration or traveling at highway speeds.