But the show is on the road, with proponent Oven Mountain Pumped Storage (OMPS) taking the first steps on the planning process this week.

The project will be the "battery of the New England" once it's completed in about 2026, providing firming for as much as one-eighth of the power generated in state's largest renewable energy zone.

That's according to OMPS Director Anthony Melov, who said the hydroelectric project would be probably the largest in the country, outside Tasmania's enormous Battery of the Nation project and the Snowy Mountains 2.0 scheme.

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He said the company aimed to get the project environmental impact statement and development application before government planners before the end of the first quarter of 2022.

The billion-dollar power plan issued its first scoping report to the Department of Planning, Industry and Environment this week.

"We think that we can firm around a gigwatt - 1000 megawatts - or so of renewables. And that's with what we're calling long-duration storage. So what we're providing with our pumped hydro scheme is up to 12 hours of storage. That means you can provide 600 megawatts for up the 12 hours," he said.

"That can help to iron out variability of renewables over a reasonably long period of time. It's not sort of a one for one relationship. That 600 megawatts of power can firm up a significantly greater amount of renewables.

"The dream being to facilitate a reliable drive towards a low-cost and clean power source."

The Oven Mountain project was given critical state infrastructure status last year, which will make development approval smoother.

The project will cost over a billion dollars, and will take between three to four years to build. During construction, it will employ about 600 full-time workers.

Mr Melov said the project would also require major upgrades to the notorious Armidale-Kempsey road, among other community benefits.

"We think we're a material part of the transition in the New England region, and for NSW more broadly, but you need other forms of storage and transmission augmentation to sit alongside us to facilitate the rollout of that quantum of renewables," he said.

The project would use two natural granite basins about 60 kilometres south-east of Armidale as a battery, pumping water uphill with surplus power and converting gravity into energy in an underground power station potentially during an electricity shortage.

The project will require a one-off flush of water from Macleay River, but won't require damming it.