Contact Energy has revised its security of supply proposal for Lake Hāwea, saying "recently received” modelling means it can reduce the lake’s proposed contingent storage level from six metres to two.

But the Guardians of Lake Hāwea say the revised proposal carries the same concerns as the original - such as dust storms and the potential for water shortages.

“Contact Energy’s recent announcement of a revised fast track proposal serves to underscore that their original proposal for new operating contingency levels was not evidence based nor sustainable,” the group said this week. 

Contact has written to stakeholders advising the change to the Fast-Track proposal it lodged with the Minister for Infrastructure in June.

“Since lodging our referral application, we’ve modified the proposal to reflect further energy system modelling we received recently,’’ Contact head of hydro generation Boyd Brinsdon said.  

“In the rare event that Transpower declared a national energy emergency, we’re now proposing to lower Lake Hāwea’s level by a maximum of two metres from the existing consented contingent storage level to 334 metres above sea level (masl). 

“This is [a] significant reduction to the original proposal that was to be able to lower the lake level by up to six metres (to 330 metres) in an emergency event.”

The proposal would still mean a change to the lake’s normal operating range (to be lowered to 336 masl). 

Boyd said the modelling “indicates that recent developments to support national energy security have reduced the need for a larger drawdown of the lake”.

He said this “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 lakebed”. 

The Guardians, however, say these concerns would remain in the revised proposal, in which Contact would make the current contingency level part of the normal operating range.

Guardians of Lake Hāwea members (from left) Geoff Kernick, Don Robertson, and John Langley, with Meredith Smith (Kane Road Utilities Society), Bill Macdonald (Camphill Estate Utilities Society), and (front) Lake Hāwea resident Rimma Kade.

Nor were the Guardians convinced by Contact’s argument that the revised proposal is consistent with a recent agreement between Guardians of Lakes Manapouri and Te Anau and Meridian Energy.

That claim “is politically mischievous and has no evidence base nor bearing on the potential impacts on Lake Hāwea”, the group said.

“Guardians’ position remains unchanged - the proposal is unsustainable and is primarily driven by Contact’s mandate to deliver dividends and increase its share price.”

Boyd said at 336masl the lake “would naturally refill, particularly in spring and summer when inflows are higher and other renewable energy sources such as wind and solar are more readily available”. 

He said the energy company is planning community consultation over the coming months, and if the proposal is accepted it would involve a “specialist community advisory group… to help inform our application process”. 

The Minister for Infrastructure is considering whether the proposal qualifies for the Fast track Approvals Act.  

PHOTOS: Wānaka App

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Dry bores and dust storms - community groups raise more concerns over lake level proposal