Wind power in New Zealand

As of early 2008, wind power in New Zealand has an installed capacity of 321 MW, nearly double the 2006 capacity. Wind power now provides enough electricity to meet the needs of 145,000 New Zealand households, and supplies approximately 2.5% of the country's electricity demand. A further 172.6 MW of wind farms is under construction, with approval being sought for another 2,054 MW.

Wind resources
New Zealand has outstanding wind resources, due to its position astride the Roaring Forties, resulting in nearly continuous strong westerly winds over many locations, unimpeded by other nearby landmasses at similar latitude. One study found that using 1% of total available land for wind farms would produce approximately 100,000 gigawatt hours (GWh) per year. This is roughly three times the annual electricity consumption of New Zealand in 2001. Nearly continuous however does not mean continuous: a high-pressure weather system can cover the entire country, meaning no significant winds anywhere.

Acceptance
Wind farms and turbines generate a wide range of opinions from outright opposition to widespread acceptance. Opposition is due to noise, aesthetics and ecological factors.

Wind turbines
Wind turbines have been installed at Southbridge in Canterbury, Gebbies Pass near Christchurch and at Brooklyn in Wellington.

Generation in 2007
Data on wind power generation is gathered by the Electricity Commission.

Coping with intermittency


Wind farms partner nicely with hydro plants on the same grid to create combined power plants, because hydro plants can be uprated with extra turbine units to provide highly dispatchable peak generating capacity above the average flows of their rivers, at lower cost than other peak power options. During periods of high wind and low electricity demand, a hydro plant can reduce its output to accumulate water in its reservoir, whilst wind power handles a higher share of the grid load. Then during periods of low wind, the hydro plant can raise its output temporarily, drawing down its reservoir a bit. Given New Zealand's large proportion of hydroelectric generating capacity, it is better-positioned than most nations to uprate its generating stations and grid to handle intermittent power sources such as wind and solar. The available virtual energy storage represented by hydro plants can be one of the main factors limiting the maximum amount of wind and solar power that a grid can accommodate. Further increases in intermittent power source development may require construction of pumped-storage hydroelectricity and implementation of energy demand management techniques.

Other nations also plan to generate more of their electricity from renewable sources, and are researching solutions for the intermittency problem. The Institute for Solar Energy Supply Technology of the University of Kassel pilot-tested a combined power plant linking solar, wind, biogas and hydrostorage to provide load-following power around the clock, entirely from renewable sources. According to a 2007 Stanford University study published in the Journal of Applied Meteorology and Climatology, interconnecting ten or more wind farms allows 33 to 47% of the total energy produced to be used as reliable, baseload electric power, as long as minimum criteria are met for wind speed and turbine height.