New Zealand has great wind resources, which are making an increasing contribution to our electricity supply.
How wind energy works
Wind turns turbine blades connected to generators that convert the wind’s energy into electricity. The faster the wind blows, the faster the blades turn and the more electricity is generated.
Turbines generate electricity between specific high and low wind speeds, shutting down when wind exceeds a turbine’s maximum level. Blade size determines a turbine’s maximum power output.
Turbines range in size from 1 kW domestic units to Europe’s offshore 12 MW turbines. The largest capacity wind turbines in New Zealand are the 3 MW units at the Tararua and Mahinerangi wind farms.
Pros and cons of wind energy
New Zealand’s windswept landscape gives us one of the best wind resources in the world. Wind turbines don’t produce greenhouse gas emissions as they generate electricity and are easy to remove, making wind power one of the most environmentally friendly forms of electricity generation. Wind energy infrastructure is also fast to build relative to hydro and geothermal power stations.
International studies show wind farms have no effect on health. Some people object to the sight of wind farms and the noise they make but stricter building codes for farms and noise standards for turbines have made wind-powered generation quieter. Wind power is a popular among New Zealanders, with three-quarters of us supporting wind farms.
Wind farm operators can forecast with reasonable accuracy how much electricity they’ll generate in a year, despite changes in wind speed. The long term stability of wind generation makes it a good fit with hydroelectric generation, which can be less stable during dry periods.
The future of wind energy
There is potential for wind to generate much more of our electricity than the 5% it does now. The lower costs of building wind farms and the close fit between wind and hydro generation mean we’re likely to see more wind farms built as our demand for electricity grows.
Currently New Zealand has 19 wind farms operating or under construction which provide 690 MW of electricity generation capacity. Over 2 GW of wind farms have been consented with the next expected wind farm to be producing electricity in late 2020.
Internationally, there has been significant development in offshore wind. Offshore winds are faster than onshore allowing for larger turbine capacities. New Zealand currently has no offshore wind farms.
Small wind turbines can be useful as part of a stand-alone power system but vibration problems, getting consent for masts in built-up areas, wind shielding from neighbouring properties and the difference in value of imported and exported electricity mean they’re unlikely to be widely used in urban settings.