Wind And Rain Warmly Welcomed

Following the driest start to the year on record, New Zealand’s largest electricity generator says this week’s weather fronts have provided a timely top-up to the hydro lakes and boost to wind generation.

Up to 300mm of rain has fallen in the Waiau catchment, with lesser quantities for the Waitaki catchment since the weekend, which the company says equates to about three weeks of additional hydro generation at Manapōuri.

“It buys us time,” says Meridian GM Wholesale Chris Ewers.

“We do need more rain to fall over the next couple of months to support us over winter, but it was still very welcome.”

“It’s not just water that’s useful. The weather fronts that bring rain also increase wind generation, which helps ease the pressure on hydro generation and allows us to store that water for the future.”

Over the last two days Meridian’s wind farms lifted from 10% to 30% of Meridian’s total generation.

“The good news is that after a quiet couple of months, most of our wind farms have this week been hitting or nearing their maximum capacity, and our newest wind farm, Harapaki in Hawke’s Bay, achieved a whopping 174MW on Tuesday.”

Following months of gradual decline, Lake Pūkaki - New Zealand’s largest hydro storage lake - has held largely steady since 15 March and enjoyed a very modest increase of around 12cm since the morning of 18 March.

It is the first lift in the level of Lake Pūkaki since late 2024. Pūkaki is currently sitting at around 70% of its historical average for the time of year, while New Zealand’s overall hydro storage is currently sitting about 75% of average.

While around 60% of New Zealand’s electricity comes from hydro generation, only 23% of that capacity can be stored in lakes, and Meridian’s own lake storage equates to only 15 weeks of average generation.

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