Democratic Sen. Michael Bennet of Colorado and Republican Sen. Dean Heller of Nevada on Thursday introduced a bill into Congress that would allow more solar companies to benefit from the Investment Tax Credit.

The Renewable Energy Parity Act of 2014 would make firms eligible for the tax credit for projects that are under construction before the credit expires on Dec. 31, 2016. Currently, only projects that are placed in service by the 2016 deadline, meaning they're complete and capable of generating power, are eligible for the credit.

The change would be particularly helpful for large projects that might take several years to develop.

In addition to solar, the tax credit covers other renewable energy technologies such as fuel cells, microturbines and small/offshore wind. The value of the credit varies from 10 percent to 30 percent depending on technology. For solar, it is 30 percent.

"Investing in alternative-energy sources cuts right to the core of whether and how we want to compete in the global and changing economy," Bennet said in a press release. "As Congress considers comprehensive energy-tax reform, we ought to provide certainty in the interim by extending the existing slate of renewable tax credits and providing parity for the solar industry."

Colorado has 328 solar companies employing about 3,600 people, according to the release from Bennet's office, while Nevada has 79 companies supporting 2,400 workers.

"Utility scale renewable projects take time to develop properly, and this bill will assist in getting more projects online in Colorado and around the country," said Chris Shapard, executive director of the Colorado Cleantech Industries Association.