Plug-in electric vehicles are decades away from replacing conventional cars, according to a senior executive at General Motors Australian unit Holden.

Energy and environment director, Richard Marshall, told The Age plug-in cars would remain too expensive for average motorists to consider replacing their petrol cars in the short to medium term.

"It took almost 100 years for shipping transport to move from sail to steam power," he said. "It won't take 100 years for electric vehicles but it will take several decades until the market is dominated by electric vehicles. If people are thinking it's going to be like mobile phones, where they went from incredibly expensive status symbols to relatively affordable, commonplace items in a very short time period, then they're wrong."

In the meantime, it made more sense to the company to reduce oil use through more-efficient internal combustion engines and alternative fuels, including biodiesel, ethanol, LPG and compressed natural gas, he told the paper.

"We need to do other things; we can't sit around and wait for electric vehicles to become cheaper," he said. "We need a multi-path approach."

He said alternative fuels would provide a better environmental outcome than zero emission vehicles in the short term because they were cheaper and would attract enough buyers to cut carbon dioxide emissions substantially.

Holden would be selling E85 Commodores (which can run on a blend of up to 85 per cent ethanol) by next year.

Marshall told The Age ethanol was an attractive option because fuel sources were widely available in Australia, it was affordable and it offered a "whole of life" reduction in CO2 of up to 94%, depending on the fuel source.

He said Australia was well placed to develop ethanol sources, with native eucalypt and melaleuca trees providing good potential ethanol sources.

Sugar cane was also a ready source.