Transpower is a state-owned enterprise with a dual role - grid owner and system operator.

We build, maintain and own the national high voltage electricity transmission grid that connects generators of electricity with users directly and via local lines companies around the country.

Our transmission network consists of 170 substations, 25,000 transmission towers, and more than 11,000 kilometres of lines that run the length and breadth of the country across public and private land. These lines and substations transport bulk electricity up to 220,000 volts from where it is generated to cities, towns and some major industrial users. Our national grid operating centres NGOC operate the grid in real time.

We are also contracted by the Electricity Authority to operate the wholesale electricity market through which generators sell electricity to retailers who then supply consumers. As System Operator, we ensure supply (provided by generators) matches demand (by electricity users) and manage system security. This is done in real time – 24 hours a day, 365 days of the year via our National Coordination Centres (NCC). 

Our key business activities are regulated by the Commerce Commission and the Electricity Authority.