New Zealand is generally recognised as having has one of the best wind resources of any country in the world thanks to its location, with the country lying across the prevailing westerly winds in an area long referred to by sailors as the 'Roaring Forties'.
New Zealand is exposed to winds travelling across the ocean un-interrupted by other land forms. A fairly steady succession of troughs and depressions passes to the east of the country, creating the predominantly westerly wind flow.
As each of these weather systems passes the country it creates a pressure difference, and therefore wind flow pattern over the mountains. In some locations this wind flow is just about continuous and can be of relatively high speed, making these areas well suited to wind energy development.
Wind farm developers spend considerable effort measuring windflow and understanding local wind conditions when investigating wind farm sites. They use sophisticated computer models to identify good sites and then take actual wind speed measurements to finalise the selection of a wind farm site and turbine locations.
Generating potential of NZ’s wind
At the moment, wind provides about 4.5% of New Zealand’s electricity (1931 gigawatt hours in the year to December 2011).
An assessment of New Zealand’s wind resource shows that New Zealand’s wind has the potential to be used to generate over three times New Zealand’s current annual electricity demand (43000 gigawatt hours in the year to December 2009).
It is highly unlikely that wind’s potential will be realised to this extent for a number of reasons, including advantages of drawing on a variety of forms of generation to meet demand. Diversity in generation enables a system to respond and maintain supply even when there is a serious problem with one form of generation (for example, low hydro lake inflows, an unexpected fault with a thermal station or calm wind conditions).
A more likely scenario is that by 2030 New Zealand will have 2500 to 3000 megawatts of installed wind energy capacity, supplying 20 percent of our electricity. In this scenario there would be clusters of wind farms in areas with good wind conditions, such as the Waikato, Manawatu, the Wellington region, Central Otago and Southland.
Regional renewable energy assessments
The Energy and Efficiency Conservation Authority has worked with regional councils to identify what renewable energy resources they have in their area, and then how to integrate this information into their planning and strategy processes. Regional reports for the following regions can be downloaded from the EECA website:
- Bay of Plenty
- West Coast