More than a quarter of South Australia's electricity was generated by wind last year, up from 18 per cent in 2010.

The proportion was less than 1 per cent five years ago, according to new results published in Energy Quest's Energy Quarterly, which updates the oil and gas industry.

Adelaide-based energy economics group EnergyQuest chief executive Dr Graeme Bethune said he was surprised to find wind responsible for 26 per cent of South Australian electricity last year.

“One of the interesting things too is that it does seem to have displaced coal,” Dr Bethune said. “The theory was that wind would need to be backed up by gas-fired generation. Gas-fired generation has fallen a bit, but the big fall has been in coal.”

Since 2006-07, the share of gas in power generation has fallen from 58 per cent to 49 per cent, he said. But the big change has been in coal, which fell from 42 per cent to 25 per cent.

SA has the highest wind farm capacity in the country and more than half the nation's installed wind capacity. Victoria is next in line, generating about a third as much wind power – but only two per cent of that state's total electricity.

Australia-wide, 80 per cent of electricity generated in the National Electricity Market was fuelled by coal, 11 per cent by gas, six per cent by hydro and three per cent by wind.

Earlier this month, University of Edinburgh economics professor Gordon Hughes claimed the cost of wind was 10 times that of a gas-fired power station.

But Windlab Systemsfound SA's wholesale electricity prices had gone down over the past five years.

Chief operating officer Luke Osborne said the electricity network managed to accommodate the increase in wind power without increasing the amount of electricity required from even more expensive “peaking power plants” – gas power plants that are turned on in times of high demand.

“We're getting over 20 per cent of electricity now in SA from wind power but it hasn't pushed up prices at all,” he said.

“That's because every half an hour all the generators on the system compete to supply the demand … Anytime we have wind going, we can kick out the most expensive bid.”