Iwi concerns factor in battery project decision

Dozens of sites in the North Island were initially identified for hydro development to help with the planned battery project but all have come up short, with iwi concerns and the defence force scrubbing the final candidate left standing.

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Last week, it was announced two options remain on the table for the battery project — an enlarged Lake Onslow in Central Otago or a mixed portfolio approach using various technologies.

Ministry of Business, Innovation and Employment NZ battery project acting manager Susan Hall said Niwa was commissioned to identify possible sites for a pumped hydro scheme in the North Island.

It was to be smaller than the South Island hydro project as the bulk of the demand for power is closer to the hydro stations in the North Island.

Niwa identified dozens of sites, of which only two were identified worth investigating further: Upper Moawhango and Taruarau River, both in the central North Island.

The other locations were ruled out for being not practical, for example, located in a national park or in or close to towns or cities.

Following a desktop assessment, the Taruarau River option was ruled out on feasibility grounds, including "constructability" and water availability.

These two options, along with Lake Onslow, were the only pumped hydro sites considered in some detail by the NZ battery project.

The NZ battery project has been in discussion with iwi in the Upper Moawhango area and the New Zealand Defence Force, Ms Hall said.

Following discussions with these main affected parties, it is apparent this concept comes with unique and significant challenges.

Ms Hall said the development of earlier power schemes remained a source of grievance for some iwi with interests in the area, particularly regarding the lack of consultation at the time, and ongoing environmental, cultural and spiritual harm caused by reduced water flows into the river that are diverted to power the scheme. This option also posed significant challenges for the New Zealand Defence Force.

A pumped hydro scheme would have flooded a critically important and irreplaceable training area for the NZDF.

Cabinet decided no further work would be done on the option through the NZ Battery Project.

"Work to date has not established whether a pumped hydro scheme on the Upper Moawhango River could meaningfully or practically provide cover in a dry year event."

Minster of Energy and Resources Megan Woods said, in a statement, any decision on either option would come next year.

"Cabinet has agreed that both options should be scrutinised further via a detailed business case on the strategic and economic factors before a decision is made mid-next year on which option should be pursued," she said.