Even without the subsidy, wind prices are getting cheaper as the technology improves. The cost of wind energy has declined by 43 percent over the last four years. There’s a backlog of projects that already qualified for the tax credit that will ensure a steady pace of turbine growth for the next few years, according to BNEF wind analyst Amy Grace.

The future of the wind tax credit is contentious and uncertain, but so is America’s cheap gas prices. As expensive coal plants are retired, utilities are switching to cheaper natural gas, driving up the price, says Grace. Also, the U.S. Energy Department is opening up domestic gas for exports for the first time. By 2020, U.S. shale gas may account for 20 percent of the global market, according to a Citigroup estimate.

If Americans have to buy gas anywhere near international market prices, wind wins. Gas may be booming, but you can expect many more wind records to come.

David Fuller's view

I suspect that at least part of that 43% drop in the cost of wind energy is due to temporary overproduction of windmills.  Nevertheless, improving technology is also a major factor.  Even so, these HG Wells monsters are appalling, noisy eyesores which blot landscapes and kill millions of birds.  

At least the USA has more undeveloped, remote land where windmills can be placed.  However, this considerably increases the costs and challenges of delivering their electricity to population centres where it is required.  In contrast, solar power need not have any of these drawbacks, while also being far more efficient and adaptable in terms of size or location.