Power cuts: Genesis boss says firm feels 'victimised' as Transpower admits error
Tuesday, 10 August 2021
Transpower made an error that made power cuts on Monday night worse than they needed to be, the company’s chief executive, Alison Andrew, has admitted.
The national grid operator asked some lines companies including Wel Networks in Hamilton to cut more power than was required by a generation shortfall on Monday night, she said.
However, Andrew has not let generator Genesis Energy off the hook for some responsibility for the outage.
About 20,000 homes in the central and eastern North Island were left without power on Monday evening after a cold snap coincided with an unplanned outage of Genesis’ Tokaanu hydro power station on the Tongariro River and a drop in wind speeds that affected wind generation.
Andrew would not comment on whether she believed Genesis had time to fire up a third coal-fired turbine at its Huntly power station in time to help meet evening peak power demand after Transpower issued a request at 1.02pm on Monday for power companies to make more generation available.
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She said that was a question for Genesis, but she suggested generators should have been keeping a close eye on the power situation and that anyone could have seen the weather forecasts.
“This an informed industry” and there was an onus on generators to make sure that they were prepared, she said.
Genesis chief executive Marc England hit back, saying the company felt “a bit victimised”.
England said if Transpower had issued a full red “emergency notice” 12 hours earlier, rather than at 5.10pm on Monday, it was possible the power crisis could have been averted.
Andrew said Transpower instructed lines companies to cut power demand by 1 per cent to avoid a worse outage, but when it converted that into the megawatt reduction required by each of the companies it accidently told some of them to cut a larger amount, and some a smaller amount, than was necessary.
Some lines companies picked up on Transpower’s error, but Wel Networks, Unison and Electra did not, she said.
In some cases, power companies could reduce demand without cutting off homes from power completely, for example by switching off hot-water systems, she said.
But Andrew said some power cuts would have inevitable even if the three lines companies had not been advised to cut more than necessary.
Even without the error, some homes would have been cut off “for sure”, she said.
Most lines companies would in the first instance drop hot-water heating, “but by the time we had the emergency, a lot of the hot-water heating load had already come off,” she said.
Lines companies would also have needed to overshoot the 1 per cent load-drop to some extent to make sure the actual target was achieved, she said.
Andrew apologised for the error but said she did not apologise for requiring a drop in demand, which she said was needed to avoid a grid emergency.
England said Genesis didn’t really have time to fire up its third Rankine unit after it received the “amber” warning from Transpower at 1.02pm.
“A Rankine unit takes six to 10 hours to ramp up before you can get any meaningful generation from it,” he said.
“We did put some thought into it yesterday morning but decided we didn’t need to,” he said.
That was because Genesis calculated it could produce the electricity it needed to supply its own retail customers and meet the contracts it had entered into with other customers, he said.
“We can’t see everybody else’s position and only Transpower gets the full picture, so really the accountability here does sit with Transpower,” he said.
By the time Genesis got the red warning at 5.10pm it was “definitely too late”, he said.
Genesis said in a separate statement that the six- to 10-hour lead time for the Rankine it referred to was from a “cold start to full load”.
England said three things happened in sequence.
“The weeds in Lake Rotoaira in the Tongariro power scheme, which are an ongoing annual issue, got out of control because of very strong south-easterly gales during the day that literally ripped the weeds out of the lake and pushed them towards the intake gate.
“The team were in control of it but lost control of it unfortunately just before the evening peak.”
England said Genesis still had “cover” at that point but about the same time, the country’s wind generation halved in a few minutes.
“That compounded the problem for the market as a whole.”
After Transpower enacted the emergency response, Transpower then asked generators including Genesis to reduce capacity. “So we had to turn down Huntly after demand fell away,” he said.
The power cuts have caused a wide range of recriminations, from suggestions they show the folly of the Government’s actions in banning new offshore oil and gas permits and its attempts to encourage the use of electric vehicles, through to arguments that they exposed the flaws in the current electricity market model.