Infigen Energy, the company that runs the Capital 1 wind farm near Bungendore, already has approval for another 41 wind turbines at the site, generating about 100 megawatts of energy.

General manager of development David Griffin confirmed his company hoped to take part in an auction expected later this year to win the right to supply the ACT with renewable energy for a guaranteed price over 20 years.

A second big project, near Collector, was approved last year for 55 wind turbines, generating 187 megawatts, and run by Ratch-Australia (80 per cent Thai owned, 20 per cent Transfield). Ratch could not be reached on Friday.

Another wind farm, near Yass with up to 152 turbines, is still before the NSW government.

Environment Minister Simon Corbell announced a vast increase in the ACT's commitment to renewable energy last week, more than doubling the cap on feed-in projects to 550 megawatts, with the bulk of the funded projects in wind farms around Canberra.

Solar would make up most of the rest, but it is undecided whether solar projects outside the ACT will qualify.

Infigen's Capital 2 wind farm was approved by the NSW government in late 2011, but Mr Griffin said it had not gone ahead because of the difficulty securing long-term agreements with retailers, reluctant to commit given the uncertainty surrounding the federal government's target for renewable energy and falling demand for electricity.

The ACT was now offering a long-term agreement.

Mr Griffin said Infigen had a large-scale 50 megawatt solar project already approved in the same area, but was waiting to find out whether that would be eligible.

Reverse auctions, also used in Brazil and South Africa, had delivered extraordinary outcomes for governments, with taxpayers the clear winners, he said. But given the risks were all on the side of the power companies, inexperienced firms must tread carefully in the prices they bid.

Mr Corbell used the reverse auctions for three large-scale solar projects in 2012 - with one being built this year near Tuggeranong, and others in train for Mugga Lane and Uriarra. The winning bids would deliver the energy at the lowest prices ever achieved in

Australia, Mr Corbell said, and an independent review out last week confirmed the winning prices were very competitive and at the lower end around the country.

Acciona Energy, which is building Royalla solar farm near Tuggeranong, is also a big owner of wind farms. Managing director Andrew Thomson would not specify whether the company had wind projects likely to bid for a slice of the action, but welcomed the news. There had been instability in national policy over the past few years, and sensible initiatives such as the ACT feed-in tariff were a good example to other governments, he said.

Renewables expert Associate Professor Iain MacGill said the ACT government was one of the few pushing ahead amid federal government uncertainty.

"The ACT is really punching above its weight in terms of driving clean energy here in Australia, and given the lack of progress in the federal and many state government policy spheres right now, it's very welcome to see a government that's still very committed to clean energy transformation," Professor MacGill, joint director of the Centre for Energy and Environmental Markets at the University of NSW, said.