Wellington - Electric Power

Electric Power

The maximum electricity demand for the Wellington region is forecast to grow on average by 1.4% annually over the next 15 years, from 756 MW in 2012 to 934 MW by 2027. (This is slightly lower than the national average demand growth of 1.7% per annum). The largest source of generation in the region is Meridian Energy's West Wind wind farm, with a maximum output of 143 MW. The West Wind wind farm is a few kilometres west of Wellington's central business district, on Quartz Hill and Terawhiti Station.There are some other small generators in the region, but the total peak generation is only 165 MW.

The peak demand in the region greatly exceeds the local generation, and power supply is therefore highly dependent on the National Grid transmission network operated by Transpower. Four 220 kV transmission circuits from Bunnythorpe, near Palmerston North, provide the main connections with the rest of the national grid. The region is also supplied by the North Island terminal of the HVDC link (the Cook Strait cable), located at Haywards substation, on State Highway 58 above the Hutt Valley. A major upgrade of the HVDC link to be commissioned in 2013 will increase the overall capacity of the link from 700 MW to 1,000 MW from 2012, and 1,200 MW from 2014.

Wellington's local power distribution network is owned and managed by Wellington Electricity. The main power supplies to the Wellington central business district come from Transpower grid exit point substations at Central Park and Wilton. The Central Park substation is the largest grid exit point in the Wellington region, with a peak demand of over 170 MW (forecast to grow to 200 MW by 2020). There are a range of constraints and limitations with this substation, and alternative investment solutions are being developed to improve future security of supply.

The strong winds of the Wellington area, while advantageous for wind farms, sometimes damage power lines. In May 2009, one windstorm left about 2500 residents without electric power for a several hours. In addition, lightning strikes and occasional faults in the electric power system sometimes cause power outages.