Power sector awaits surge

Transpower has called on power companies to fire-up more generation on Friday after cautioning that it could have only a small buffer to cope with unexpected outages during what may be record morning peak demand.

The state-owned enterprise issued a ‘‘customer advice notice’’ to power companies yesterday afternoon asking them to offer more electricity into the market between 7.30am and 9am on Friday and to make sure their forecasts of what they expect to generate during that time are accurate.

General manager of operations Stephen Jay said power demand could hit a new record on Friday morning as the cold snap moved north.

Current forecasts were also for little wind on Friday morning, he said.

‘‘To be clear, we are not anticipating any impact on electricity supply on Friday morning,’’ Jay said.

But if power demand reached predicted levels and the wind forecast was accurate, then without action from generators there would be a smaller buffer than it aimed to maintain to ensure the stability of the grid.

Morning demand commonly peaks in winter at about 6500MW and Transpower aims to keep at least 200MW of generation in reserve to cope with contingencies, such as power plant outages.

‘‘With the cold snap worsening and moving north over the country to higher population centres, we are now predicting that Friday morning could potentially see a record morning peak,’’ Jay said.

‘‘We have also been consulting closely with the MetService, which is forecasting very little wind on Friday morning, which would mean the amount of electricity generated from wind would be much smaller than expected.’’

Transpower’s notice was ‘‘an example of the system working as intended to ensure that enough generation is offered’’, he said.

Jay expected demand for electricity would fall off again on Friday evening and across the weekend.

The notice from Transpower falls short of a warning or emergency notice, which it would only issue closer to the time if supplies remained tight.