At first glance, wind power seems to be the path to a carbon-free energy future. Once harnessed, it’s clean and abundant. Larger turbines have enhanced wind’s power-generating capacity.

But contrary to its supporters, wind energy has grown thanks largely to production tax credits (2.3 cents per kilowatt hour) totaling billions of dollars. However, those credits are being phased out, and without such generous subsidies, wind energy will not make much of a dent in power production or carbon mitigation for at least a decade.

The amount of wind energy has tripled in the past 10 years, growing to 97,223 megawatts in 41 states. Half of that generating capacity is located in five of them: Texas, Iowa, Oklahoma, California and Kansas. Because seasonal wind patterns vary considerably across the country, wind’s contribution to the grid represents just 8 percent of power production nationwide.

Despite all the hoopla over wind energy, the nation’s only offshore wind turbines are located in coastal waters near Rhode Island. The Block Island Wind Farm, which went into operation in late 2016, cost $2 billion, plus $16.7 million to compensate companies that lost access to fishing grounds. Operating and maintenance expenses for wind farms currently add about $48,000 per megawatt generated.