"We think wind and solar will be a lot cheaper in 2030 than those projections,” said Mark Diesendorf, an associate professor at the UNSW, and one of the authors of the report, Least cost 100 per cent renewable electricity scenarios in the Australian National Electricity Market. “We could do it if we have the political will,” Dr Diesendorf said. “It would cost us a bit but it would be quite affordable, and it may be cheaper than we have projected.” Running simulations based on power demand and supply data for 2010, the researchers found wind would contribute most in a switch to fully renewable energy. It would account for between 46 and 59 per cent, while solar PV and concentrated solar would supply 15-20 per cent each, and hydro and biofuel-based gas generators the remainder. Australia now sources about 10 per cent of its electricity from renewable sources, an amount set to at least double by 2020 under the government's renewable energy target. The Coalition backs the goal but has vowed to repeal the carbon tax if it wins office in September. Pacific Hydro, a renewable energy generator in Australia, Chile and Brazil, said reaching 100 per cent renewable energy supply is technically feasible but obstacles are steep.

“It would take a substantial shift in political thinking,” Andrew Richards, executive manager of corporate affairs at Pacific Hydro, said. “You'd need to mobilise tens of billions in capital to make it happen.” Political differences After a bruising political fight to implement a $23 a tonne carbon tax, the government is not keen to rekindle debate over lifting the price. It would cost us a bit but it would be quite affordable Instead, the price – if it hasn't been repealed – is likely to fall after July 2015 when the rate is linked to Europe's emissions trading scheme where prices are hovering below $6 a tonne.

“The level of the carbon price is likely to move with international carbon prices as countries act together to cut emissions,” said a spokesman for Climate Change Minister Greg Combet. The Coalition, meanwhile, argues the existing renewable energy target is driving sufficient investment to the sector. “To drive up the carbon tax to $100 would largely make electricity unaffordable for most Australians who are already struggling to pay their power bills, and put thousands of jobs at risk because of the impact it would have on manufacturing,” said opposition climate spokesman Greg Hunt. “When commentators put forward these proposals they need to be honest with the public about what the real costs would be for people's power bills." Greens leader Christine Milne, though, described the UNSW research as “hugely significant”. “For decades opponents of the renewable energy revolution have peddled the lie that renewable energy is unreliable and expensive,” Senator Milne said. “This independent and rigorous academic report exposes that lie.”

Senator Milne noted the Multi Party Climate Change Committee ordered the Australian Energy Market Operator to conduct a similar study to determine the feasibility and cost of achieving 100 per cent renewable energy by 2030 and 2050. AEMO delivered its findings to the government on Tuesday. It is understood the release of the report is not imminent. Subsidies Pacific Hydro's Mr Richards said calls for additional renewable energy support should be viewed in light of the International Monetary Fund's report last week that energy subsidies total $US1.9 trillion a year, mostly for fossil fuels. “You need to slowly unwind [those subsidies] at the same time you ramp up the positive stuff,” Mr Richards said. “Then you'll start to see the transition more quickly.”

Loading Many other countries are setting high goals, including Scotland's aim to generate all its power from renewable sources by 2020. Demark has bipartisan political support to achieve 100 per cent by 2050, while Germany's goal of cutting greenhouse gas emissions 80 per cent by 2050 will be driven mostly by the power sector. “They are not just talking about it – they are doing it,” Dr Diesendorf said. “Australia has huge potential because of our magnificent renewable sources but politically it's more difficult because of our very powerful fossil-fuel and minerals industries, which are very reluctant to change.”