Power bills will rise when Transpower starts upgrading a stretch of the national grid next summer.
Haywards substation. Photo: RNZ / Diego Opatowski
The Commerce Commission has approved the replacement and upgrade of the lines between Manawatu and Hutt Valley.
The upgrade between the Bunnythorpe and Haywards Hill substation will cost $161 million.
The consumer will pay 0.4 cents more per kilowatt until the work is done, which is expected to be in 2020.
Telecommunications commissioner Stephen Gale said the lines were at the end of their economic lives because of coastal corrosion, but the benefits outweight the costs.
He said the cost of not doing the upgrade would be nearly $1 billion.
