By Paul Gipe
[from Wind Energy Weekly 521, November 9, 1992]

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, Birger Madsen of the Danish firm BTM Consult, and Armin Keuper of the Deutsches Windenergie Institut, 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.

ENERGY BALANCE (PAYBACK) OF WIND TURBINES
Calculated by Three Studies

A. "Average Danish production" Source: Erik Grum-Schwensen, "The Real Cost of Wind Turbine Construction," Wind Stats, Spring 1990, Vol. 3, No. 2, pp 1-2.

B. Source: A. Gydesen. D. Maimann. P. B. Pedersen, "Renere Teknologi pa Energiomradet," Energigruppen, Fysisk Laboratorium III, Danmarks Tekniske Hoejskole, Miljoeministeriet, Miljoeprojekt Nr. 138, Denmark, 1990, pp. 123-127.

C. Source: G. Hagedorn. F. Ilmberger, "Kumulierter Energieverbrauch fuer die Herstellung von Windkraftanlagen," Forschungsstelle fuer Energiewirtschaft, Im Auftrage des Bundesministeriums fuer Forschung und Technologie, Muenchen, August 1991, pp. 79, 98, 100, 111. NOTE: In this study the primary energy used to construct the wind turbine was given in units of kWh. However, only 35% of the energy burned in a power plant is converted to useful work. To present the data from this study in a format consistent with that from the other studies, the kWh consumed has been multiplied by 0.35.

PRIMARY ENERGY PAYBACK FOR VARIOUS TYPES
OF POWER PLANTS

Source: G. Hagedorn. F. Ilmberger, "Kumulierter Energieverbrauch fuer die Herstellung von Windkraftanlagen," Forschungsstelle fuer Energiewirtschaft, Im Auftrage des Bundesministeriums fuer Forschung und Technologie, Muenchen, August 1991, pp. 79, 98, 100, 111.

EMISSION COMPARISON BETWEEN A WIND TURBINE
AND A COAL PLANT OVER 25 YEARS

Source: A. Gydesen. D. Maimann. P. B. Pedersen, "Renere Teknologipa Energiomradet," Energigruppen, Fysisk Laboratorium III, Danmarks Tekniske Hoejskole, Miljoeministeriet, Miljoeprojekt Nr. 138, Denmark, 1990, pp. 123-127.

Wind FAQ | AWEA Home Page

© 1998 by the American Wind Energy Association.
May be freely distributed provided this notice is included.
All other rights reserved.