Southern wind farms come into play

WIND farms built in the South were in full flow yesterday, as a generator says more farms planned will significantly derisk the threat of power cuts. Transpower issued a warning on Thursday afternoon about possible power cuts yesterday morning, at a time of unseasonal cold for many, because of heavy demand from consumers and generation constraints.

But the cuts did not materialise.

Consumers reduced power use yesterday morning and major industrial electricity users dialled back demand, while generators made as much electricity available as possible. Wind power is being promoted by the new government. One wind farm has just been built in the South and two more are planned in the same area. The Kaiwera Downs wind farm was opened late last year and was in full flow yesterday morning.

Other wind farms are also planned near Kaiwera, at Slopedown in Southland, and the Kaihiku wind farm in South Otago.

Wind farms have been built at Mahinerangi and Mt Stuart over the past 20 years.

Mercury Energy executive generation general manager Stew Hamilton said the company responded quickly to make more generation available on Thursday night into yesterday.

‘‘We had everything that we possibly could running at full noise — at this morning’s 8am peak we were generating about 1400MW including 67MW from our South Island wind farms,’’ Mr Hamilton said yesterday.

‘‘The turbines at Kaiwera Downs start generating at wind speeds of 10kmh and reach full capacity at around 40kmh. The sites have a capacity factor of around 40% which means that it generates 40% of its maximum potential throughout the year.’’ On Thursday night the company’s North Island wind farms were not producing due to calm conditions.

‘‘At the same time the wind farm at Kaiwera Downs was generating near maximum output of 35MW and our Mahinerangi wind farm was also producing near maximum output of 32MW.

‘‘This really highlights the importance of having generating assets in different locations all over New Zealand as we have — often when it’s still in one place it might not be elsewhere.’’ Manawa Energy and Pioneer Energy are looking to develop the widespread Kaihiku wind farm. It is planned for land about 7km from Clinton and 12km from Balclutha.

It could potentially produce 300MW, enough power for 135,000 homes.

Manawa Energy said while wind farms could drop to no output when it was still and calm, it was more likely they would still offer some reduced contribution. ‘‘Given the geographical size of the Kaihiku wind farm, it would be unusual for it to produce no generation. In addition, it is unlikely to be calm across all wind farms nationally at the same time,’’ the company wind generation team said in a statement yesterday.

‘‘During the highrisk period this [yesterday] morning, Pioneer Energy’s Mt Stuart wind farm was operating between 50% and 100% output, peaking at 6am, and dropping to 50% by midmorning. ‘‘Given the proximity of Mt Stuart to the Kaihiku wind farm site, it’s a reasonable representation of the potential performance of Kaihiku wind farm. If the Kaihiku wind farm was operational today, it would likely have contributed more than 150MW of generation, significantly derisking the national position.’’ Contact Energy declined to give details about the company’s planned Slopedown wind farm. It was hoping to build a large wind farm, set to produce between 250330MW, enough power for 110,000150,000 houses.

THE country yesterday narrowly avoided the need for power cuts as households and big industrial users rallied to conserve power on an unseasonably cold morning.

National grid operator Transpower warned on Thursday that there could be insufficient supply between 7am and 9am yesterday.

It asked people to reduce their use of power by turning off heaters and lights in unused rooms, delaying using appliances, and not charging devices and cars.

The Major Electricity Users’ Group (MEUG), which represents big industry, said the sector had freed up about 60 megawatts (MW) of power in response.

While those savings would hit production in the short term, the group’s chairman John Harbord said that was what they signed up for as responsible New Zealanders.

Despite temperatures dropping well below zero in some areas of the country, New Zealand had managed to save over 260MW, Transpower executive general manager Chantelle Bramley said.

That represented ‘‘a very significant response’’.

‘‘As you know, the situation was very tight; we’ve had really cold weather. We just want to thank New Zealanders for their fantastic response ... it has made a huge difference getting us through the morning peak.’’ Ms Bramley said Transpower had been prepared to work with lines companies to control the load if necessary, but ‘‘thankfully we didn’t get to that situation, we didn’t have to call for any further load management’’. ‘‘The networks were working really hard to manage load ... and we’ve avoided any further need to switch off supply.’’ Mr Harbord said MEUG had two concerns — one was that there was not a strong argument for spending millions of dollars on a new plant if it sat unused apart from times of big demand. The other was the mix of electricity generation; as there was more reliance on renewables, such as solar and wind, situations such as yesterday’s could arise more often.

‘‘A bit more thermal peaking would be really helpful, because the thermal sits there, you can stockpile gas and coal and turn it on almost in an instant, and the problem we have with solar and wind [is] you can’t stockpile it and save it for when you need it.’’

Energy Minister Simeon Brown said his expectation was that generators and regulators (Transpower and the Electricity Authority) would have had security of supply as a top priority going into winter. ‘‘We’ve had a number of winters where there has been tightness in recent years and there has been changes made around how information is shared, how decisions are made, how warnings are provided to ensure that the market and the system operates as best possible for consumers.

‘‘But ultimately, this is not where we want consumers to be with these types of warnings. We ultimately want a secure, reliable electricity system where Kiwis are able to stay warm . . . in winter time.’’ Transpower has said the problem with supply was due to 700MW of generation being offline due to maintenance.

But Mr Brown said ‘‘part of the reason’’ for the squeeze was that New Zealand had ‘‘old thermal generators, which means when we have to turn it on, some of it’s not always available’’.

He also blamed the previous government’s ban on new gas exploration, 2030’s ‘‘frankly impossible’’ 100% renewable target and the Lake Onslow battery scheme, which he said had a ‘‘chilling effect’’ on new investment from the market. Labour Party energy spokeswoman Megan Woods rejected that, saying the country needed ways to store electricity.

The Lake Onslow battery scheme would have done that, she said, but the coalition government had ditched it and had no plans for other storage options.

Ms Bramley said Transpower was not concerned about any further supply issues at this stage.

‘‘We’re expecting pressure to drop off later this afternoon; we’re not looking at any potential issues over the coming days,’’ she said yesterday.

The 700MW that were currently offline due to maintenance were due to come back online over the next few weeks. She said the timing of future maintenance would be looked at, but said investment in the system was also necessary to make sure there were enough flexible resources to be able to respond to unseasonably cold days.