"We estimate that expanding wind generation will reduce wholesale prices at the rate of around 9¢ per MWh, per one MWh of additional wind generation," it said. "For solar - almost all of which has so far been on household roofs - we estimate the wholesale price reduction at the rate of around 26¢/MWh, per one MWh of additional solar production." Bruce Mountain, director of the centre and the lead author of the report, said there was no longer an industry trade-off between power prices, reliability and greenhouse gas emissions. "Maybe there was a trilemma at some point of time but it ain't there any more," Associate Professor Mountain said. "There is no dilemma between a cleaner power system and cheaper power.” Dr Bruce Mountain says 'the market left to itself will bring in wind and solar'. Credit:Wayne Taylor The report's release comes as the Morrison government scrambles to develop a new energy policy following the demise in August of the proposed National Energy Guarantee. Promoted by then prime minister Malcolm Turnbull, the policy aimed to lower emissions, improve reliability and put downward pressure on prices.

Loading The government has ditched emissions as part of its priorities, and is instead seeking increased legislative power to force energy companies, particularly retailers, to offer customers cheaper deals or face penalties. "The government has been clear we want a fairer deal for Australian families and small businesses," Energy Minister Angus Taylor has said. "Energy retailers need to work quickly to deliver fairer, lower prices as soon as possible." But Professor Mountain said if the objective is to bring prices down, "you ought to be hastening the entry of cleaner sources more quickly than otherwise would happen".

"There is no doubt that the market left to itself will bring in wind and solar but if you bring it in more quickly and it can pay for itself so handsomely why would you not seek to do it?" he said, adding that the SA experience would be mirrored in other states such as Victoria, NSW and Queensland. Battery anniversary On Wednesday, the 100MW Hornsdale Power Reserve built by Tesla, marked its first year of operation with Neoen claiming it had "exceeded all performance and market expectations", citing an independent report. The battery, whose capital costs have been reported as $90 million, had saved almost $40 million a year in Frequency Control Ancillary Service, benefiting SA and other regions. It had also been able to provide grid support "thousands of times", kicking in with a response time of less than 100 milliseconds, the company said.

The Hornsdale battery in SA built by Tesla has had a successful first year, its owners Neoen say. A spokesman for the Liberal SA government - elected since the battery's commencement - was less upbeat. "South Australian taxpayers paid a very high price for Labor’s failure to plan for a sensible transition to renewable energy," the spokesman said. "While the battery is helping, it’s addressing a very expensive problem which Labor caused." Professor Mountain said the battery "seems to have been very profitable for the owner, who got the government to stump most of the cost for it”.

While the storage showed that "a little bit of capacity" can still have a big impact in SA, it is not clear the future effects will be as favourable for other such projects. "These things are rooting out lots of evils but once the evils are rooted out that golden bonus doesn’t exist anymore, so costs will need to come down [if the success is to be repeated]," he said.