Waikato and Upper North Island Voltage Management Investigation

Region Map
Auckland population
1.5 M
...and increasing
Thermal generation decom. since 2012
Improved voltage support
to meet Auckland's needs

Latest updates

We have submitted our Major Capex (MCP) Proposal submission to the Commerce Commission for approval to ensure the supply of electricity remains stable in the Waikato and upper North Island in coming years. The application and accompanying documents can be found in the downloads section below.

In parallel to the application, Transpower is also exploring non-transmission solutions that may supplement or defer some of the transmission solutions. If we identify reliable and economic options we will update our proposal.

A draft decision from the Commerce Commission is expected in May, with a final decision following in August.

A need to investigate

Since 2012, over 1000 MW of generation capacity has been decommissioned in the Waikato and Upper North Island regions. This generation reduction coupled with the actual and expected demand growth in the Waikato and Upper North Island raises significant voltage stability risks. The potential loss of the two remaining Huntly Rankine units further increases this risk.

The critical risks are transient under - and over-voltage events that could cause voltage collapse if not managed. Efficient voltage management is essential to the reliable delivery of power.

What are the potential solutions

There are many ways of supporting voltage such as by using capacitors, synchronous condensers, statcoms and SVCs, but potentially also demand response and generation solutions.  Moreover, the issue is complex and a portfolio of different assets – at various locations and commissioned at different times – rather than a single asset solution is needed. 

After three years of in-depth analysis, we are proposing a mix of reliable and economic non-transmission solutions, reactive power plant and a demand management scheme. We detail our progress in our consultation documents, accompanying reports and updates, which can be found below.