Sites near Australia’s coal-fired power stations may be used to store solar energy and shift the grid away from fossil fuels

While coal still makes up more than 50 per cent of east-coast electricity supplies, officials think it could be gone from the grid entirely by as early as 2040, making Australia’s transition to renewables one of the fastest in the world. But in a grid that’s soon to be dominated by intermittent wind and solar, the energy market operator warns a sharp lift in investment in assets that can store renewable energy will be critical to keeping the lights on.

So far, electric utilities and governments have been mostly focusing on building out a fleet of grid-scale lithium-ion batteries, which absorb surplus renewable energy to inject critical bursts of power into the grid when needed. Another prominent storage technology is pumped hydro, which uses motors to pump water uphill to a higher reservoir, then release it downhill to spin turbines connected to generators whenever the grid needs topping up.

However, both technologies have their limits: today’s batteries exhaust their stored energy in two to four hours of maximum output, minimising their ability to plug longer solar or wind shortfalls. Pumped hydro, meanwhile, can run for many hours or days, but requires significant height differentials over short distances, such as mountain ranges, which the industry says makes it difficult to carry out construction on time and on budget.

As Australia’s shift from coal to renewables continues at pace, proponents of long-duration storage technologies argue the deployment of assets that can dispatch for beyond eight hours looms as the “missing link” needed to ensure a smooth energy transition. Among the other long-duration storage technologies being planned across Australia are concentrated solar thermal, which uses thousands of mirrors to focus solar rays on receiver points to capture heat and store it; compressed-air storage, which pumps air into underground chambers; and vanadium redox flow batteries, which use different chemistries to lithium-ion batteries and are typically longer-lasting.

Following Energy Dome’s successful start-up of a 2.5-megawatt demonstration plant in Sardinia, O’Doherty said interest in its technology, which can run for 30-plus years without degrading, was “surging” as the company neared completion of a full-scale 200-megawatt unit. It has been awarded a contract from Alliant Energy in the US, and NTPC, India’s largest power company, he said.

“While there are many long-duration energy storage concepts out there, very few are on the verge of delivering power to the grid,” he said.

Victoria’s Minister for Economic Growth and Jobs Danny Pearson said Energy Dome’s move would bring world-leading technology to Melbourne, create jobs and contribute to the state’s economic growth.

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