Somebody asked me the other day what the life cycle impacts of a wind turbine are and how long it would take to pay back the energy used to manufacture one of those tall majestic beasts. Considerable amounts of raw materials and energy are required to make these big windy wonders. I was stumped of course as that information is not something one can just come up with. I found this report on Renewable Energy Access from 2005, which looks like an answer to that question for two models by Danish manufacturer, Vesta.
The life cycle assessment of a 3.0 MW wind turbine indicates that it would have to generate electricity for only 6.8 months , of their assumed 20 year useful life, before it produces as much energy as is used during the manufacturing phase. "This, they say, means the turbine model earns its own worth more than 35 times during its energy production lifetime." Read the article here. Image credit: Sandia National Laboratories.