Cheaper electricity prices could be on the way.
Genesis Energy is trialling smart meters in 300,000 houses, to record electricity consumption by the half hour.
Newstalk ZB business correspondent Roger Kerr says it could eventually lead to time of day pricing.
He says the idea is to shift power usage at peak times.
"A good example is putting on the dishwasher or the clothes dryer late at night to get a cheaper rate, so a customer of Genesis will be able to take a variable pricing plan that provides dollar incentives to not use electricity at peak times."
Roger Kerr says if the whole country does that, the demand shifts, reducing peak consumption and the need to build more electricity plants.