In August Mr Taylor said any mechanism design would be technology neutral and open to any form of dispatchable power.
Ms D’Ambrosio’s intervention also sets up a robust discussion for next week, when all state and territory energy ministers are scheduled to discuss the next design steps for such a capacity mechanism.
Australia’s grid is burdened with some of the oldest plants in the developed world as well as some of the fastest renewables growth, given the country’s rich wind and solar resources.
The challenge is to reduce the risk of sudden coal-fired power plant closures, such as Hazelwood’s exit in 2017, while also maintaining sufficient supplies when the wind isn’t blowing or the sun isn’t shining. Victoria may be joined by other jurisdictions, including the ACT, in opposing any beefed-up reliability obligations that extend the life of coal plants.
The Commonwealth’s advisory body, the Energy Security Board, last month issued its final recommendations on the future of the NEM. It backed a system that would make retailers pay generators to have enough so-called dispatchable energy capacity on standby to fill supply gaps.
Kerry Schott, chair of the Energy Security Board, has sought to allay concerns existing fossil fuel-fired generators will have their operational lives lengthened.
“One principle in the design of the mechanism, for example, could – and I would think, would – be that thermal ageing generators do not stay in the NEM one minute longer than necessary,” Ms Schott told the AFR last month.
Ms D’Ambrosio, though, made it clear that those assurances weren’t enough.
Victoria has sought further modelling from the board on what a capacity mechanism would mean for individual types of generation, such as coal or gas, but that work was not done.
“This is disappointing, and the longer this drags out the growth in uncertainty amongst renewable energy investors continues,” Ms D’Ambrosio said. “Will it actually deliver the smooth transition that we need? The jury’s still out on that.”
Costings of a capacity market have not been published, and final details may take 18 months of work.
Despite her warnings over the new scheme, Ms D’Ambrosio has already cut a deal to ensure one coal plant stayed open until 2028.
She revealed in May that EnergyAustralia had agreed to keep the Yallourn coal plant open until 2028, despite the challenging economic outlook, bringing the closure forward four years from its initial exit date in 2032. She did not reveal the details, citing commercial confidence.
Bruce Mountain, director of the Victoria Energy Policy Centre, said the board has been in the “invidious” position of trying to deliver an outcome that Mr Taylor wants that may not square with the states’ interests. “They have been trying to please two masters,” Professor Mountain said.
“If they take sides with the state governments they have the possibility of implementing something. But if they take sides with the Commonwealth the states will block it. The ESB is in an impossible position.”
From an engineering and economic perspective, relying on coal power to back up renewable variability made no sense because such generators cannot switch on and off rapidly, Professor Mountain said. Pumped hydro and batteries would be far more flexible.
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