Wind generation in New Zealand
In 2012, wind provided enough electricity to power the whole of New Zealand for 17 days. Visit www.em6live.co.nz to find out how much electricity is being generated by wind farms right now.
Quarterly wind generation
||% of total generation
(Source: New Zealand Energy Quarterly, Ministry of Business, Innovation and Employment)
The combined capacity – or the rated output – of wind farms in New Zealand is 622 megawatts. What this means is that at any given moment, if all wind farms were operating at full capacity they could produce 622 megawatts of electricity.
Wind turbines in New Zealand operate about 90% of the time, but the amount of electricity they generate is dependent on wind conditions. This is why wind generation is often referred to as “variable generation”.
Over the span of a year, New Zealand wind farms generate at an average of around 40% of their rated output - this figure is also referred as “capacity factor” and is among the highest in the world.
Capacity factor is defined as the amount of electricity actually generated relative to the amount that would have been produced if the generator had been running at its full output over the same period. Capacity factor is not a measure of efficiency, nor a measure of the time spent operating.
No form of generation produces electricity at its full output, 100% of the time, so a capacity factor of less than 100% does not mean a form of generation is unreliable. Hydro generation has an annual average capacity factor of around 50%, gas 65%, geothermal 80%. Generators are often offline because of maintenance, unexpected faults, fluctuations in demand or constrained fuel supply.
New Zealand's total operational generating capacity
||Operational capacity at year end 2012
Source: Energy in NZ, 2013 edition, Ministry of Business, Innovation and Employment.