For him and his wife, Lynette, the opportunity to host wind turbines on their 700-hectare property, about 110 kilometres north of Canberra, may have come a little too late.

But the lamb farmer hopes the growing wind-energy industry will help lure young people back to the bush, and says the federal government must maintain its backing for renewable energy.

"There is a possibility that one [of my children] could move back here and help to improve the farm and make it more productive - if the renewable energy target is not changed," Mr Magee told a rally of activists outside Parliament House on Sunday, Global Wind Energy Day.

"There is a further possibility that others ... may gain employment in the area. The economic benefits would help stop the drift to larger cities."

A review of the so-called RET - an aim for 20 per cent of the nation's electricity to come from renewable sources by 2020 - is due to be completed shortly, amid fears the Abbott government will reduce the target or scrap it entirely.

Last month, Treasurer Joe Hockey launched an unprompted attack on windfarms near Lake George, just outside the ACT, telling conservative radio commentator Alan Jones he found them "utterly offensive" and "a blight on the landscape".

Climate activists have also noted that the RET review's leader, former Caltex chairman Dick Warburton, and other panel members have close links to the fossil-fuel industry.

Mr Magee said he could not understand the Treasurer's view. "It could be argued that the very same four-lane freeway he was travelling on is more offensive and a bigger blight on the landscape, and indeed the urban development that has ruined the north shore of Sydney," he said, referring to Mr Hockey's electorate.

Small groups of residents near windfarms occasionally oppose the industry, saying turbines are noisy and reduce rural property prices.

However, NSW government polling in 2010 found almost nine in 10 residents in the region near the ACT border supported windfarms, including 61 per cent of people who lived one to two kilometres away from turbines.

Regardless of what happens to the federal RET scheme, ACT Environment Minister Simon Corbell told the rally that Canberra would maintain the nation's most ambitious renewable energy policy: 90 per cent of the ACT's electricity would be sourced from renewable energy by 2020.

He also noted that the Royalla solar farm - the largest in Australia - was just a few months' away from being commissioned.

"The sad thing about that project is that it's only 20 megawatts. When you look at renewable energy and solar energy around the world, you see that so many nations are investing in schemes and in projects that are in the hundreds of megawatts.

"In a country like Australia, we should be doing the same."

Sunday's rally preceded the 2014 Community Energy Congress, which will be held on Monday and Tuesday at the National Library. About 300 delegates are expected to attend from across Australia and overseas.