At first glance, wind power seems to be an extraordinarily clean energy source, but even without accounting for any negative environmental effects at individual installation sites, there's still a price to pay in terms of the global warming potential, or GWP, involved in the manufacturing of the turbines.
However, a new study claims that "greener" electricity can be generated from the wind by building bigger turbines, with a reduction of GWP per kWh of 14% for every cumulative production doubling of size.
The study, Wind Power Electricity: The Bigger the Turbine, The Greener the Electricity? analyzed the life cycle of various phases in wind turbines, including the extraction of resources for manufacturing, the processing and manufacturing of those materials, transportation to the installation site, maintenance of the turbines, and disposal of the units. The study included all the major parts of wind turbine systems, and covered a range of turbine rotor diameters from 40 to 300 feet across.
According to the results of the study, the larger the wind turbine is, the greener the electricity becomes. This effect is said to be for two different reasons: Manufacturers of turbines now have much greater knowledge and experience to draw on in making the design and manufacturing process more efficient, and recent advances in materials and technology enable the building of larger blades that can harness more wind without proportional increases in their mass or the amount of resources needed to build or transport them (the turbine itself, as well as the tower and other components).
"A doubling of the size does not double material consumption." - Marloes Caduff, researcher and environmental scientist at the Swiss Federal Institute of Technology
The researchers do offer a caveat about the results, as they caution that their results are only based on wind turbines with rotors up to around 300 feet in diameter, and the data does not support an extrapolation to larger sized turbines in the future.