National grid operator Transpower has taken further steps to boost electricity reliability in the upper North Island.
Transpower estimates the winter demand for power in the upper North Island will rise by 62% over the next 20 years.
To meet that, more electricity will flow along a new transmission system being constructed between south Waikato and Auckland.
The increased flow will create a heightened need for voltage stability.
As a result, Transpower is seeking approval from the Electricity Commission to spend between $103 million and $110 million, and pass the cost on.
The money would buy technical installations that support voltage levels.