http://www.sciencedaily.com/releases/2014/06/140616093317.htm http://www.sciencedaily.com/releases/2014/06/140616093317.ht... says "a wind turbine with a work

http://www.sciencedaily.com/releases/2014/06/140616093317.htm http://www.sciencedaily.com/releases/2014/06/140616093317.ht... says "a wind turbine with a working life of 20 years will offer a net benefit within five to eight months of being brought online" that's 150 to 240 days with a lifetime of 7300 days.