FAQs
How long does it take for a turbine to 'pay back' the electricity
used to manufacture it?
The comparison of energy used in manufacture with the energy
produced by a power station is known as the 'energy balance'.
It can be expressed in terms of energy 'pay back' time, i.e.
as the time needed to generate the equivalent amount of energy
used in manufacturing the wind turbine or power station.
It is estimated that the average wind farm will pay back
the energy used in its manufacture within three to five months,
and over its lifetime a wind turbine will produce over 30
times more energy than was used in its manufacture. As New
Zealand wind turbines have an average-above capacity factor*
- it is 20% to 30% higher than the world average capacity
factor - the pay back time is probably even shorter in New
Zealand. However this is faster than coal-fired power stations,
which take about six months. When the energy used to supply
the fuel for coal power plants is included, the energy balance
for those conventional sources is clearly even poorer still,
as coal-fired power stations continually produce C02.
*Capacity factor: In New Zealand the average capacity factor
is between 40% and 50%. This means that over the course of
a year the turbine would produce 40% to 50% of the amount
it could theoretically have produce if it was working flat
out all through the year.
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