New Zealand power demand hits record as cold snap bites

New Zealand's electricity use hit a record morning peak of 7,415 MW, Transpower says, surpassing the previous record set a day earlier.

Demand rose by 168 MW from the earlier peak of 7,247 MW - roughly the electricity use of Hamilton - as cold weather lifted heating demand across the country.

The system was under pressure during the morning peak, especially in the upper North Island, where low temperatures combined with weak wind generation. Despite the tight conditions, households and businesses continued to receive power.

Earlier in the week, Transpower issued notices to industry under its standard procedures to warn of expected high demand. The alerts give generators, large industrial users and network companies time to prepare for periods when supply margins may narrow.

Large industrial users reduced demand early in the morning, while generators worked to ensure available units were online. Lines companies were also prepared to remove controllable load from the system if required, and Transpower's transmission business had the grid and the HVDC link ready.

The HVDC link is a critical part of New Zealand's power system because it moves electricity between the North and South islands. Its availability becomes more important when regional demand is uneven or generation conditions differ across the country.

Cold snap

The latest record highlights the strain winter cold spells can place on New Zealand's electricity market, where hydro, geothermal, thermal and wind generation all help balance the system. Demand typically rises sharply on cold mornings as households and businesses increase heating use before the working day begins.

Low wind added to the challenge during the peak period. When wind generation falls during a surge in demand, the system has less flexibility and operators must rely more heavily on other forms of generation and demand reductions to maintain supply.

James Kilty, Chief Executive, Transpower, described the operating conditions as tight but manageable.

"The very cold temperatures across the motu, and particularly in the top of the North Island combined with low wind meant that while it was particularly tight on the electricity system, the power stayed on for Kiwis," said James Kilty, Chief Executive, Transpower.

Transpower credited a broad industry response with helping the system withstand the morning peak. That included generation companies, large industrial consumers, local lines businesses and staff in control rooms overseeing the network.

"Thank you to everyone in the industry for the great response this week. To generators for ensuring that all units that were available to generate were, to the large industrials that reduced demand first thing this morning, to lines companies for being ready to remove controllable load from the system and to Transpower's transmission business for ensuring the grid and HVDC link were ready. Finally, to our System Operator staff working in our control rooms managing the system, thank you for your efforts to keep the power on," said Kilty.

Watching demand

Transpower was continuing to monitor conditions closely as low temperatures persisted. Similar levels of electricity demand were expected again overnight and into the next morning, raising the prospect of another period of pressure on the system.

New Zealand's power market has faced recurring winter tightness in recent years when cold weather, fuel constraints or low renewable output have converged. Morning and evening peaks are watched especially closely because they test whether enough generation and transmission are available at short notice.

For Transpower, the latest record underscores the central role of system coordination rather than generation volume alone. Maintaining supply during extreme demand periods depends on timing, transmission availability, regional balance and the willingness of some large consumers to reduce load when asked.

"We are keeping a close eye on the cold temperatures tonight and particularly tomorrow morning when we are expecting similar levels of electricity demand," said Kilty.