Billions of dollars in renewable-energy tax credits are still up in the air after the U.S. House of Representatives voted to extend them Friday.

That's because the House-approved bill offsets the cost of the credits - slated to expire at the end of the year - by reducing tax subsidies for oil and gas companies, and adding other taxes elsewhere.

The House and Senate disagree about how to pay for the incentives, and the Senate has previously rejected a number of other bills that would have eliminated the corporate subsidies (see Senate Rejects Renewable Tax Credits Bill, Senate Blocks Renewable Incentives Bill, Renewable Tax Incentive Still at Risk, As National Incentives Fail, States to Fuel Renewables, Senate Rejects Green Incentives to Pass Energy Bill and Senate Sends Energy Bill Back to Beginning).

The House voted, 226-166, to amend a proposal the Senate approved Tuesday, which in turn amended a bill the House approved in May (see Senate OKs $18B in Tax Credits).

The bill also cuts out tax incentives for oil-shale and tar-sands development and for technology to turn coal into liquid fuels.

Both bills extend solar-investment credits for eight years, solar-, biomass- and hydropower-production credits for two years and wind-production credits for one year, among other incentives.

In a statement Friday, House Speaker Nancy Pelosi, D-Calif., said the House version would reduce dependence on foreign oil by increasing the production of renewable energy and encouraging greater energy efficiency.

"These provisions are critical to creating and preserving more than 500,000 good-paying green-collar American jobs in the wind and solar industries alone," she said in the statement. "Congress can wrap this up today. The Senate should seize this opportunity to pass this bill."

The Senate didn't approve the bill Friday, and it's unclear whether it will be able to take another vote on the issue before recessing. While lawmakers planned to end the Congressional session Friday, they are staying to negotiate a bank bailout.

Negotiations on the proposed $700 billion bailout package postponed a vote the House originally expected to hold Thursday.

A procedural error also contributed to the delay, when the House submitted the bill under the wrong number, according to Monique Hanis, director of communications at the Solar Energy Industries Association.