I was at a wind farm near Palm Springs, CA. I noticed quite a high percentage of units (probably 10-15%) not functioning, and some (5% or so) obviously derelict, rusted with pieces lying around on the ground. I was told it's cheaper to build a new one than fix an old one. Our guide told us the main thing to fail is the transmission, which is a large part of the cost. When it goes, they just leave the turbine out there doing nothing and build a new one for the tax credits.
He said GE was very bad about this. I think part of the cost should be for clean up, if it breaks, you need to take it out.