How much energy does it take to build a wind system in
relation to the energy it produces?
It has been calculated that it takes just 100 days (1.4% of its lifetime production)
for each turbine to pay back the energy costs used in its own construction.
The energy generated by wind turbines pays for the materials used to make
them in a matter of months, according to three separate European studies.
The question, thought by industry analysts to have been effectively
answered during the 1970s, has been raised anew recently by some critics
of proposed new wind power plants, who have questioned whether the energy
produced by a wind turbine justifies its construction.
The question possibly arises from now-dated findings on the net energy
pay-back of solar photovoltaic cells, according to Jos Beurskens, manager
of renewable energy for the Dutch national energy research center ECN.
Early solar cells had a negative energy balance, Beurskens said, but more
recent products perform far better and pay back the energy consumed in
their manufacture within ten years. As the performance of photovoltaics
improves, so too will their energy balance.
In contrast to photovoltaics, Beurskens said, wind turbines typically pay
for themselves in a matter of months.
With the assistance of Beurskens,Wind Energy Weekly has pieced together statistics
from two Danish and one
German examination of wind's energy balance. The results, including full citations,
are presented in the accompanying tables for use by the
industry.
The German study, by far the most extensive, examined wind turbines from
10 kW to 3 MW in size, while both Danish studies considered a "typical"
Danish wind turbine of the period. The results of all three studies are
comparable: utility-scale wind turbines installed in areas with
commercially usable wind resources will pay for themselves within one
year.
As expected, much of the energy used to manufacture the turbine is
contained in the rotor and nacelle. But more than one-third of the total
energy consumed by the wind turbine is contained in the concrete
foundation and tower.
The Danish study for the Ministry of the Environment also estimated that a
coal-fired power plant emits 360 times more SOx, NOx, and carbon dioxide
to generate an equivalent amount of electricity over the 25-year life of a
wind turbine.
| SOx | NOx | CO2
|
|---|
| Wind | 40 kg | 0.3 kg | 87 kg
|
|---|
| Coal | 14 t | 108 t | 31.3 t
|
|---|
To return to the table of contents, please press Index.
Index
Sources:
Parts from "wind power theory" and "energy systems" taken from "netscape miracle".