Across Australia’s eastern seaboard, the urgent need to scale up energy storage is coming into ever sharper focus. Coal-fired power generators, which today supply two-thirds of our electricity needs, are increasingly bringing forward their closures dates, owing to the influx of renewables pummelling their profitability during daytime hours, ageing plant infrastructure driving up maintenance bills, and pressure from their own shareholders to commit to faster and deeper emissions cuts. AGL retired its Liddell power plant in NSW earlier this year, and, by 2030, at least four more are due to close too.

The Australian Energy Market Operator, which is overseeing the grid’s transition, has declared that the grid’s “most pressing need” over the next decade is for dispatchable batteries, pumped hydro or alternative storage to manage daily and seasonal variations in the output from rapidly growing solar and wind generation.

Pumped hydro – a technology that pumps water uphill to a higher reservoir and then releases it downhill to spin turbines when it’s needed – has enormous potential. The biggest problem, however, is that it’s very difficult to deploy at a large scale. Suitable geographic sites such as steep mountain ranges are hard to secure, and are often in heavily bushed, remote and complex terrain. They also present significant challenges and costs in terms of construction and connectivity to the grid.

Seeking to minimise such hurdles, North Harbour is taking an approach of pursuing only mid-size, not mega-sized, pumped hydro projects, which they will locate closer to large customer loads, and on disturbed land where possible. One of its projects will repurpose a disused mining-related shaft as the pipe that connects its two reservoirs.

“I suspect we are a couple of years away to get to a final investment decision on our first pumped hydro project, then probably two or three years to get to operations,” Schultz says. “I think we will have vanadium flow battery installations before we’ll have pumped hydro projects in place – in fact, we are very well-advanced on a couple of those projects right now.”

Made from the little-known metal vanadium, this battery technology was invented at the University of NSW in 1983 by a chemical engineer, Professor Maria Skyllas-Kazacos. Japan’s Mitsubishi acquired a licence to use the technology in the 1990s.

In the years that came next, some flow batteries began being deployed commercially. Sumitomo has been manufacturing them, an Austrian company has had them running for 10 years, and a Chinese company has just completed the first stage of a 200-megawatt vanadium flow battery in Dalian. But demand for long-duration grid storage was not large, and its success has been eclipsed by the hugely popular lithium-ion batteries, which are storing power for everything from our smallest electric devices, to electric vehicles to energy grids.

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Proponents of vanadium batteries agree that lithium-ion batteries are perfectly suited an array of applications, and will be in huge demand in the era of battery-powered electric cars, which are expected to suck up by far the biggest share of available global lithium supplies. But when it comes to stationary energy grid storage, vanadium flow batteries boast some meaningful advantages. They may have a higher up-front cost, but they are much longer lasting, can run up to 20 years without degrading, and are non-flammable.

As the 2030s approach, questions are being asked about our readiness to handle the reduction of coal power, and our ability to meet the federal government’s goal for the grid to be 82 per cent renewable.

"We need concerted and collective action by the industry and by governments and the community to enable that to happen, and I think we are a ways away from that," says Schultz. "It is still doable, but it’s a very large challenge – the sooner we get on with it, the better."

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