Siege being defined as the low cost of gas and the end of federal subsidies. 

This Bloomberg report in the Albuquerque Journal News describes the problems with building wind energy since the end of the Federal subsidies worth $23/MWh to the turbines and the drop in the cost of natural gas caused by the expansion of hydraulic fracturing.  “Power-purchase agreements in the U.S. are under severe pricing pressure because of the shale gas boom,” said Jurgen Zeschky, CEO of Nordex, a German wind-turbine maker. “That’s putting pressure on prices for wind power and makes investments very difficult.”  Congress is considering restoration of subsidies, but may not act during the election season.

I’m not sure how this article came up with construction costs, but  EIA estimatesshow on-shore wind projects about twice the cost per kilowatt as gas projects.  Wind projects seem to dry up when the subsidies dry up.