Cyclone Gabrielle: Esk River hydro stations still out of action

The Esk River hydro-electric scheme comprises two sites that began construction in 2012.

A 3.8 megawatt hydro-electric power source in the Esk River is likely to remain offline for another six to 12 months.

The Manawa Energy-run stations suffered damage in Cyclone Gabrielle, with continued access issues delaying their repair. The stations sit on the Maungaharuru Range, inland from Lake Tūtira.

The sites - known as Rimu (2.4 megawatts) and Toronui (1.4 megawatts) - are on private land and do not have storage lakes, a Manawa Energy spokesman said. Built between 2012 and 2013, the stations collect water in a weir, which is then piped hundreds of metres downhill.

That is then said to generate enough power to supply about 1900 homes.

“Specifically on the Toronui power station, the team advised it had held up pretty well, with the small weir, head pond and station building all substantially intact,” the Manawa Energy spokesman said.

“At the Rimu power station, the head pond and station building survived, but the small intake weir has been effectively washed away, and the access road and penstock have gone too.”

Neither power station has on-site staff, but they are monitored “from time to time.”

“[But] we have been providing support on the ground to the landowner and his workers,” the spokesman said.

That includes access to a helicopter and the delivery of food, fuel, a generator and enabling satellite phone communications.

It is not known to what extent - if any - damage done to the power stations contributed to the levels of water that deluged Esk Valley during Cyclone Gabrielle.

The spokesman said “largely, conveyancing structures, transmission assets and surrounding land” were impacted by the weather event.

“Most of the actual electricity generation equipment remains in good condition,” he said.