"If there is too much power coming from the grid, wind turbines have to be shut down. Nevertheless, consumers are still paying for the "phantom electricity" the turbines are theoretically generating. Occasionally, Germany has to pay fees to dump already subsidized green energy, creating what experts refer to as "negative electricity prices."
On the other hand, when the wind suddenly stops blowing, and in particular during the cold season, supply becomes scarce. That's when heavy oil and coal power plants have to be fired up to close the gap, which is why Germany's energy producers in 2012 actually released more climate-damaging carbon dioxide into the atmosphere than in 2011."
If you add in the use of rare sand mining in China, the CO2 produced in their construction and installation and the decommissioning costs. Every time a turbine goes up we are worse off. All we can do is hope that the next government has the balls to get out of them and discourage their use.