Another impediment to CNG is limited range. Compressed natural gas is nonetheless one of the best existing alternatives. Ethanol has been seen in the past to be an excellent alternative to gasoline. Although ethanol is domestically produced as a by-product of corn, gains in air quality due to the use of this fuel can be considered negligible at best. It should not be considered a viable alternative.
Methanol suffers from many of the same problems as ethanol.
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.