Rain gives hydro lake levels a boost

Manapouri Power Station. Photo: ODT files
Manapouri Power Station. Photo: ODT files

Rain has brought relief to some of the country’s hydro lakes that had been at historic low levels.

Meridian Energy general manager Chris Ewers said in a statement the situation for the southern hydro lakes was improving by the day, with persistent rain and snowfall over the past fortnight providing a welcome boost to lake and snow levels.

"We’ve been saying all along that it’s a battle of inches - and after a long, dry winter it’s good to see lake levels going in the right direction.

"The level of Lake Pūkaki has increased by over a metre since its lowest point just under two weeks ago, with a further 300mm-400mm of rainfall forecast over the next couple of weeks, and Lakes Manapōuri and Te Anau are now into their high ranges.

"That’ll mean strong generation out of Manapōuri Power Station for the next few weeks."

The hydro lakes have been under the microscope after Transpower put forward a proposal allowing generators to access "contingency storage" - which is stored hydro that is only made available for generation at specific times to mitigate the risk of shortage — much earlier than normally allowed.

"Throughout June and July storage was as low as 50% of average, but substantial snowfall over the last month means it is now sitting at 83% of average," Mr Ewers said.

"We always knew the rains would come eventually, and spring usually sees a change in weather patterns. There’s still some way to go but with more rain expected this week it’s looking more encouraging day by day."

Meridian’s wind farms have continued to perform well, with all six regularly generating at or near their maximum capacity over the last seven days to produce a total of 57GWh.