New Zealand is burning a lot of coal to keep the lights on at the moment.

Last night between 6 pm and 7:30 pm, the diesel generator was turned on.

At 6 pm New Zealand hit the highest peak demand on the power grid since records began.

While there's been enough power generated to meet the demand, Huntly Station has had to activate its diesel generator to keep up.

Energy commentator Molly Melhuish says it can turn on through shortage or high demand, but this is the first time the diesel generator has been used this year.

“Last year it was turned on very few times and for the previous three or four or five years, it was never run.”

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