Modern wind turbines of typical utility wind farm scale — 1.5 MW and up — pay back energy used in their full-lifecycle — materials, manufacturing, construction, use and decommissioning — in less than six months.
Wind turbine manufacturers have a vested interest in accurate full lifecycle cost assessments (LCA) and publish these. To maintain ISO certification — a necessity for any manufacturer to sell to more than backyard hobbyists — LCAs are required to be published and available. They must follow manufacturing standard ISO 14040-14043 approaches to costing. They must be independently reviewed. What is relevant from these LCAs is that every step of manufacturing, transport, construction, operation, maintenance and dis-assembly is captured and quantified. Literally everything of any significance is measured and included in the calculations.
This example shows typical full-lifecycle accounting results for all aspects of a modern 2 MW GE wind turbine. Note that it shows 146 days for payback for all of the energy used to manufacture, ship, construct, operate and decommission and 94 days for all of the CO2 and other greenhouse gases emitted over the full life as well.
In this comparison, you’ll see that the two generation technologies with the highest energy payback ratio are wind and wind with pumped-hydro storage. A high ratio is good in this case.
GE provides nuclear power plants, photovoltaics, natural gas generators and coal plant technology. They have full-lifecycle analyses of all forms of generation using apples-to-apples, ISO methodologies to make the comparisons above.
The following chart is relevant to discussion of modern wind energy, as opposed to historical wind energy. The chart shows that the larger the wind turbine, the greater the energy and environmental payback. At present, GE and other are working at the 4.5 MW and 6 MW scale. The largest turbine in the comparison is 800 KW, much smaller than current scale, so larger wind turbines will have even better ratios.
LCAs for all wind turbines are published and available for assessment. This one was selected as an example, but all show roughly the same results. Wind energy is very competitive with other forms of energy on all fronts.
Where does this leave us?
Wind farms pay back total environmental debt in every category very quickly, much faster than virtually every other form of large scale electricity generation.