Pumped Hydro Holdings Ltd, a consortium with four directors, had revived the battery project last year after it had been mothballed by the incoming National-led government at the end of 2023.
It had now got out of the blocks and if it all went to plan it could be operating in less than 10 years.
Pumped Hydro Holdings Ltd director Keith Turner said the consortium had the full support of the landowners where the project would operate and it would have an impact on electricity power prices.
"It is an absolute game changer. And it does get me very excited, because I think it will do a great deal for New Zealand.
"I’ve always felt that New Zealand has more than enough renewable and indigenous energy sources to serve its country. It’s a real competitive advantage to have your own resources and to be competitive in the world.
"I’m old enough to know that back in the ’70s and ’80s the electricity price in New Zealand was the lowest or second lowest in the OECD."
It was a project ideally suited for the fast-track process.
"This is the sort of project that fast track was really intended for — large infrastructure projects that would be very slow to do otherwise."
The project could cost just over half of what the Labour government-backed project was budgeted for.
"The costings have been pretty widely represented in the public arena as sort of $1`5 billion-$17b, but those numbers are not correct. If you go to the MBIE project files, the capital cost of the project is somewhere between $8.5b and $10b, depending on how big a bottom pond you have. Those $15b to $17b numbers were not the capital cost at all," Mr Turner said.
Mr Turner, a former Meridian Energy chief executive, said the MBIE costs ballooned as they included life-time operation costs and life-time financing costs.
The Lake Onslow project will help in dry years, stabilising electricity supply and the price of power, acting as a backup supplier
"Not only will it stimulate investment, it will bring electricity into the transport and industry sectors and it will actually keep prices down."
He said plenty of work had been put in over the past six months to get referred into the fast-track programme and more would come when the substantive application was processed.
Mr Turner hoped the fast-track application did not take too long.
"We could put the resource consent together in six months.We know that’s ambitious, but look, we are a small, nimble team.
"We want to do things quickly and get this project going. But it may be longer. That’s certainly our objective anyway."
The final design of the project would not be known until after approval was gained.
He said there had been plenty of interest from companies, both from New Zealand and overseas, to invest in the project.
"We have been surprised, actually, by the level of interest from international investors. I mean, there are very large companies around the world that have built and owned and operated pumped hydros.
"They understand the technology. They understand the merits of it."
If all went well, they could start building the project in 2029 and have it running by 2035. It may take a couple of seasons to fill the reservoir.
It would be able to store more than 5000GWh of power, which is more than twice the annual generation of the Clyde Dam.
Lake Onslow project
• A pumped-hydro scheme works like a giant battery.
• When water is plentiful, it is pumped up from the Clutha River to Lake Onslow for storage.
• It is released in dry periods when power demand is high.
• Should bring more stable power prices.
• Designed to replace coal-fired Huntly Power Station.
