CHRIS UHLMANN, PRESENTER: A year ago Tony Abbott won office declaring Australia was "open for business", but the clean energy sector says, for it, the doors are closing.

Radical changes to the Renewable Energy Target are being considered after a review recommended it be dramatically curtailed.

That's met with scathing criticism from the head of Australia's Renewable Energy Agency. He's told 7.30 that if it was adopted, the industry would shut down.

But a grassroots campaign to protect the scheme is gathering momentum.

Political correspondent Sabra Lane reports.

SABRA LANE, REPORTER: In a picturesque spot outside Canberra, a massive solar farm - Australia's largest and the first connected to the national grid, was commissioned this week.

Project developer Spanish company FRV was on hand to witness the switch-on. So too, Spain's Foreign Minister.

JOSE MANUEL GARCIA-MARGALLO, SPANISH FOREIGN MINISTER: The Spanish Government is convinced that the future of energy is - lies on renewables. Australia has all the potential to become a superpower in this field.

SABRA LANE: But industry supporters say the future's cloudy. They believe the sector will be devastated if the Warburton Review recommendations into the Renewable Energy Target, known as RET, are adopted by the Federal Government.

ANDREA FONTANA, FOTOWATIO RENEWABLE VENTURES: So probably what that would mean is that we would have to withdraw from all of the developments and the $3 billion worth projects that we are - in our pipeline.

SABRA LANE: The RET was put in place by the Howard Government and tweaked in 2010 to ensure that 20 per cent of Australia's power would be generated by renewable resources by 2020, effectively giving industry support to renewables at the expense of established fossil fuel electricity generators. There are two targets within the scheme: a large-scale RET covering projects like hydro, solar and wind farms, and a small-scale RET, covering rooftop solar panels and solar hot-water heaters.

In law, the 20 per cent figure's expressed as 41,000 gigawatt hours. But given electricity demand has been falling, that amount will actually equate to something like 26 per cent by 2020.

The Warburton Review recommended closing the large scheme to new entrants and shutting it by 2030, or, that it be ditched, with the renewable sector limited to a 50 per cent share of new growth in electricity demand. That's what some now call a "true 20 per cent" figure.

GREG BOURNE, ARENA CHAIRMAN: It's a choice between being hung or being shot.

SABRA LANE: Greg Bourne is the chairman of ARENA, the Australian Renewable Energy Agency. One of its objectives is to increase the supply of renewable energy in Australia. The Government wants it scrapped, but the hostile Senate won't agree.

GREG BOURNE: The signal that's being put forward here is, "We are closed for business. We actually don't want the renewable energy, we want coal-fired power stations, we want some gas-fired power stations."

DICK WARBURTON, RET REVIEW HEAD: This program was not set up to set up businesses, it was set up to try and encourage renewables into the marketplace, which it's done and that's a good side of it, but it's not necessary at the moment. And the big subsidies just being misspent when they could be put into other areas.

SABRA LANE: The Energy Supply Association represents electricity retailers and generators, and they want the RET scaled back.

MATTHEW WARREN, ENERGY SUPPLY ASSOCIATION OF AUST.: The challenges of transforming the energy market are bigger than just what size the target is. But a true 20 per cent is probably the most credible way of getting the investment going in renewables that we need to continue that transformation.

SABRA LANE: The Government's stressed the review is a report to the Government, not of the Government. Already, community tension is rising over what it might do.

FIONA O'HEHIR, CEO GREENBANK ENVIRONMENTAL: I suppose the message I send to Tony Abbott and to his sidekick Joe "Screaming Meemie" Joe, right, is strap another grenade to your chest, boys, because we're here ready to pull the pin.

SABRA LANE: Across the ACT border in Queanbeyan, solar industry workers and supporters met last night to discuss the review.

AUDIENCE MEMBER: In the seven years that I've been involved in this industry, I'm yet to have to sack one of my long-term employees (waves at someone) - call out to them up the back. I certainly hope that this won't be the first step in that.

SABRA LANE: The Solar Council wants the status quo and has launched a grassroots campaign targeting marginal Coalition electorates.

JOHN GRIMES, SOLAR COUNCIL: Let's see what happens in the electorates of Eden Monaro and of Petrie and of Reid and of Barton and of Dobell and Corangamite.

SABRA LANE: In the Victorian seat of Corangamite, 24 per cent of homes have solar PV systems or solar hot-water. Sarah Henderson's the local Liberal member. She's not convinced by the report's recommendations.

SARAH HENDERSON, LIBERAL MP: The feedback that I am receiving, the industry is concerned about ensuring that there is the confidence to continue invest in renewables. And we've got to make sure that whatever we do - and of course I'm just one part of the backbench - but we've got to make sure that we continue to drive strong confidence in the renewable energy sector.

MATT CANAVAN, LIBERAL-NATIONAL PARTY SENATOR: We don't so much have a renewable energy target; we have a reduced economy tax.

SABRA LANE: Queensland LNP Senator Matthew Canavan says current investors must be protected, but he wants the scheme gradually phased out.

MATT CANAVAN: The RET is no different than other forms of industry assistance; we never try and put them in place forever. There should be a time limit on these things and industries either grow up or we move on, because if we just continually provide people assistance, they'll never have the incentive to be more efficient and grow up from being the infant.

SABRA LANE: The review found renewables have stopped power prices from rising as fast, but keeping the scheme as is would result in a further $22 billion in cross-subsidies to the renewable sector.

GREG BOURNE: Let's face it: you've got a tiny company taking on incumbents who have been there for 30, 40, 50, 70 years who actually do not want to yield ground. So the renewable energy technologies are disruptive, they're disruptive to the status quo, and automatically, the gloves are put on by the incumbents to batter down anyone who is coming through.

SABRA LANE: Mr Bourne says the Warburton findings were pre-ordained and that chairman Dick Warburton is known for his climate sceptic views.

DICK WARBURTON: My thoughts are well-known. However, that had nothing to do with this particular review. There's nothing in the terms of reference to do with that. There's nothing in the terms of articles we put out.

SABRA LANE: It's a political hot potato for the Government. Cabinet is wrestling with the findings and is expected to have a response by the end of the month. 7.30's been told some within cabinet are keen to find a middle ground, and it needs to, especially with the small-scale target, as it is extremely popular. Whatever happens, the Government's changes will have pass the Senate, and if the Palmer Party's words can be trusted, there'll be no change.

GLENN LAZARUS, PUP SENATOR LEADER: The Renewable Energy Target is working. If the Renewable Energy Target is to be changed, this should only happen in response to the will of the people, not climate change sceptics. I believe the Warburton Review has failed to make a case to cut the Renewable Energy Target.

CHRIS UHLMANN: Sabra Lane reporting.