General Electric saw a drop in demand for its wind power turbines to around half of its 2009 sales levels as power companies turned to natural gas for cheaper alternative energy forms, the company said on a conference call.

GE is the top supplier of wind turbines for some of the nation’s largest wind power farms — huge swathes of land dotted by giant windmills that use the wind to generate anywhere from 1 to 3 megawatts of power per windmill. Each turbine and wind farm typically carries enormous upfront capital costs that can take several years before the power company can recoup its costs.

Wind turbines also carry a certain stigma with them — they can be an eyesore for some residents, who fear it will reduce property home values. Several wind power companies have thrown up their hands when trying to develop wind power farms due to a rapidly changing regulatory landscape. The “not-in-my-backyard” argument is pretty common among renewable energy sources, even if wind farms and other kinds of renewable energy sources don’t negatively affect property values.

GE said it was committed to developing wind power regardless of the downturn in denabd in the U.S. Wind power companies have begun manufacturing farms that can generate around 5,600 megawatts as of the beginning of 2011, according to reports.

Wind power deployment in the U.S. stalled last year after growing for 3 years consecutively. The U.S. only added 5,116 megawatts’ worth of wind turbines, down from more than 10,000 megawatts in 2009. The U.S. has so far deployed wind turbines that can generate around 40,200 megawatts of electricity — enough to power around 10 million homes.

California recently passed a law requiring around a third of California’s power to come from renewable energy sources. The law could prove to be a major incentive for clean technology companies in the state to begin ramping up their production of clean energy sources. That might lead to more companies buying additional turbines from GE and other wind power turbine manufacturers.