U.S. Sen. Chuck Grassley, R-Iowa, and Iowa Gov. Terry Branstad led a bipartisan call today for Congress to approve a multi-year extension of the renewable energy production tax credit that they called critical to the wind energy industry.

The lame duck Congress “needs to pass at least the one-year extension,” Grassley said at a Washington news conference.

Uncertainty about the tax credit is hurting wind energy production and local communities where wind energy-related manufacturers are laying off workers, Branstad added.

“Thousands of jobs in the wind industry have already been impacted by the credit’s looming expiration, and thousands more are at risk,” Branstad and Oregon Gov. John Kitzhaber wrote to congressional leaders. “We urge you to take swift action to extend the (production tax credit) before the end of this congressional session.”

Without an extension, it is estimated that the U.S. economy will lose 37,000 wind industry jobs and the opportunity to leverage more than $10 billion in private investment, they said.

In Iowa, Clipper Windpower in Cedar Rapids has laid off about 100 employees and Siemens in Fort Madison has announced the layoffs of about 400 more, Branstad said.

The industry needs about five years to mature, Grassley said, adding that “it would be a mistake to throw away that investment” at a time when wind energy can help meet energy needs, create jobs and reduce pollution.

The extension rests in part on the ongoing discussions between President Obama and Speaker of the House John Boehner, R-Ohio, Grassley said.