Expanding Lake Onslow to create a storage battery for New Zealand’s power needs is definitely not a done deal, officials say.
Farmers, whose land would be flooded if the project went ahead, remain unable to make future plans until any final decisions are made.
A final decision will be at least two years away.
The Ministry of Business, Innovation and Employment (MBIE) gave an update on the NZ Battery Project — specifically on phase 1, which includes the Lake Onslow option — during a community open day at the Roxburgh Town Hall on Saturday.
The first session of the day was attended by more than 70 residents, MBIE energy projects manager David Darby said.
Lake Onslow, which is located east of Roxburgh and south of Alexandra, is only one option being investigated to address the country’s "dry year problem" — when hydro-power lakes run low and fossil fuels must be burned to generate enough energy for the country’s needs.
A battery at a smaller lake in the North Island had been discussed, but that option remained in the concept phase and would require a lot of iwi and stakeholder engagement before MBIE even considered a geotechnical investigation, Mr Darby said.
Part of the NZ Battery Project included looking at pumped hydro technology, which was used successfully as a stored energy option for hydroelectricity with large schemes in the United States, United Kingdom, China and Japan.
Other options the MBIE was investigating for energy storage in phase 1 were newer and less known, such as hydrogen, bioenergy and new ways of using geothermal energy.
"Onslow is definitely not a done deal," Mr Darby said.
"It will be subject to a Cabinet agreement in early December to move to the next stage of the battery project and, if so, in what form."
The NZ Battery Project had yet to spend all of the $30 million allocated for investigation, and if the project moved to phase 2 — a detailed business case looking at technical, commercial, environmental, social and recreational impacts — $70 million had been set aside, he said.
"That is a very big ‘if’."
Phase 2 was expected to take at least two years, "possibly more".
Phase 3 — construction of any battery or storage solution — could take more than seven years after phase 2.
Former Teviot Valley Community Board chairman and fifth-generation farmer Raymond Gunn was at the open day as part of NZ Battery Project technical reference group.
He said most residents had an open mind and were eager to learn more about the potential project.
"Some people think it’s too expensive and it’s never going to happen.
"Some people are quite excited about it and the possibility of growth in this valley."
Most farmers who would be directly affected by flooding if Lake Onslow was expanded would rather not see it happen, Mr Gunn said.
"It has caused a lot of uncertainty for them in the next two or three years, because the pin could be pulled by the Government at any time.
"Succession planning ... or general planning on how your farm operates — it’s all up in the air."
