By Rory Carroll

LAS VEGAS (Reuters) - Congress will vote to extend a $12 billion federal tax credit for utility-scale wind energy projects that is in danger of expiring at the end of the year, Senate Majority Leader Harry Reid said at a clean energy summit in Las Vegas on Tuesday.

The credit provides a production tax break for wind energy of 2.1 cents per kilowatt hour, an incentive that the industry says is essential to developing more wind farms and supporting jobs at wind manufacturing plants.

"We will get it done before the end of the year, I'm very confident," Reid said during a press conference on the sidelines of the fifth-annual Clean Energy Summit.

"We may even get this done before the election," he said.

The head of the world's biggest wind turbine maker, Denmark's Vestas Wind Systems, has said that the U.S. wind turbine market would likely fall by 80 percent next year if the credit expired. The decision is also being closely watched by manufacturers such as the U.S.'s General Electric, Germany's Siemens, Spain's Gamesa and India's Suzlon Energy.

Reid's comments come after a 19-5 bipartisan vote by the Senate Finance Committee on August 2 in favor of the credit.

The tax credit had been added to a package of measures known as "tax extenders" because they expire annually and are typically extended.

Despite Reid's statement that the wind tax credit will be extended, the provision will still need the support of the Republican-held House of Representatives. Some Republicans say the wind industry is mature enough that it no longer requires government support.

Democratic President Barack Obama has urged Congress to extend the credit, while Republican presidential candidate Mitt Romney favors letting the credit expire.

Reid's comments come as wind power in the United States has reached 50 gigawatts of electric generating capacity, enough to power 13 million homes, a milestone announced by the American Wind Energy Association on Tuesday.

(Editing by Jonathan Weber and Steve Orlofsky)