Consent given for increase in water yield

Meridian Energy has been given approval to release more water through its Manapouri tailrace, increasing electricity generation in the south.

The company's proposal, the Manapouri Tailrace Amended Discharge, was approved by an Environment Southland consents panel. It gives Meridian permission to lift its maximum instantaneous discharge limit into Doubtful Sound from 510 cubic metres a second of freshwater to not exceeding 550cumec, when conditions permit.

The scheme will lift annual electricity generation at the Manapouri power station by 89GWh, enough to power about 11,000 homes. The increased output requires more water to be diverted from the Waiau catchment.

Meridian spokeswoman Claire Shaw yesterday said the extra generation would also provide greater security of supply.

The scheme, which did not require any infrastructural changes, was the best way of getting the most out of an existing asset, she said. "And it's important for everyone to know that it will only operate at increased capacity when conditions permit."

That was when lake levels were high enough or after a significant rainfall event, she said.

Overall, the Manapouri Power Station is expected to increase generation capacity by about 2.6 per cent. The additional electricity would not be funnelled directly to Southland consumers, instead into the national grid, she said. But like other sources of generation it would likely flow to the nearest point of demand, Ms Shaw said.

More power from the station would not necessarily mean cheaper electricity, but it should guard against price fluctuations, she said. She could not say when the amended discharge would be activated.

The consents approved were two water permits and one coastal permit which all expire on November 28, 2031. A host of conditions has been attached to the consents by the panel, aiming to reduce the environmental effects of the amended discharge, a source of consternation by submitters that opposed the application during the hearing process.

Among the submitters' concerns were water quality in the Waiau Arm, the wellbeing of the Lower Waiau River, the Doubtful Sound bottlenose dolphin, longfin eel migration and small-boat safety in Deep Cove.

Any appeals of the panel's decision must be received within 15 working days.

- © Fairfax NZ News

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