The view from a Department of Conservation Lake Hāwea walking track. Photo: Supplied/ Department of Conservation
Contact Energy has scaled back part of a controversial plan to take more water from Lake Hāwea, near Wānaka, to boost renewable energy generation and help safeguard electricity supply.
The gentailer is seeking fast track consent to lower the lake's minimum operating level from 338 to 336 metres, but has now revised a proposal to drop the level to 330 metres in extreme cases - like extra dry years - by setting a new 334-metre limit.
The current emergency limit was 336 metres.
Locals told a packed public meeting in September that they were worried a big drop in the lake's level could affect their water supplies and cause dust storms.
In a written update this week, Contact Energy's head of generation Boyd Brinsdon told Hāwea locals that company had changed its plans as a result of new data.
"Latest independent energy system modelling indicates that recent developments to support national energy security have reduced the need for a larger drawdown of the lake," he said.
"This approach also aligns with community concerns about the environmental and operational risks associated with deeper drawdowns, including slower lake refill rates, potential aquifer impacts and bore water supplies and dust from a more exposed lake bed."
At September's meeting, speakers cited a 2023 report prepared for the Otago Regional Council that found that a drop in Lake Hāwea's water levels to 330 metres would likely cause a substantial decline in groundwater and potentially lead to the failure of many bores.
Others recalled how low lake levels in the 1970s resulted in severe dust storms that blanketed the town in silt.
In a statement, advocacy group Guardians of Lake Hāwea said Contact Energy's new plans showed its original proposal was not "evidence-based nor sustainable".
"The revised proposal is justified on the basis of 'independent energy system modelling'. No such modelling was presented for the original proposal," the group said.
Guardians of Lake Hāwea said it did not accept the company's claim that its revised proposal aligned with community concerns.
The group said it was still worried about dust storms, aquifers, biodiversity loss and recreational amenity loss.
"Guardian's position remains unchanged - the proposal is unsustainable and is primarily driven by Contact's mandate to deliver dividends and increase its share price," the group said.
Brinsdon said the proposal was not about keeping the lake level low, rather enabling smarter use of stored water when it was needed most.
"Our commitment is to work with the Hāwea community on this nationally significant initiative where Contact has an obligation to support creating a more resilient, affordable energy system," he said.
Under the proposed reduction in operating levels the lake would still "naturally refill", especially in spring and summer when inflows were higher and other renewable sources like wind and solar were more readily available, Brinsdon said.
"Initial modelling highlights under this proposal, it's likely that from summer through to winter, Lake Hāwea would be held [at] slightly higher levels than it is currently."
Brinsdon said the infrastructure minister was considering whether the proposal qualified under the Fast-track Approvals Act.
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