Pipes for Transcanada Corp.'s planned Keystone XL oil pipeline are stacked at a depot in Gascoyne, N.D. The House of Representatives approved the Keystone XL pipeline Friday; the Senate voted against it on Tuesday. Andrew Cullen/Reuters/Landov hide caption

itoggle caption Andrew Cullen/Reuters/Landov

GOP Rep. Bill Cassidy and Democratic Sen. Mary Landrieu face off in a Dec. 6 Senate runoff. Both are pushing for legislation approving the remaining leg of the Keystone XL pipeline between Alberta, Canada, and Steele City, Neb. Gerald Herbert/AP hide caption

itoggle caption Gerald Herbert/AP

Pipes for TransCanada's planned Keystone XL pipeline are stored in Gascoyne, N.D. The U.S. House has voted to approve the proposed project, which would allow crude oil to flow from Canada to the Gulf of Mexico. The Senate plans to vote Tuesday on legislation that would greenlight the project. Andrew Cullen/Reuters/Landov hide caption

itoggle caption Andrew Cullen/Reuters/Landov

Sen. Mary Landrieu, D-La., chair of the Senate energy committee, spoke Wednesday about getting congressional approval for the Canada-to-Texas Keystone XL pipeline. With her is Sen. Joe Manchin, D-W.Va., a member of the committee. J. Scott Applewhite/AP hide caption

itoggle caption J. Scott Applewhite/AP

Democratic U.S. Sen. Mary Landrieu of Louisiana walks through the U.S. Capitol on Wednesday. Congress returned to work following last week's midterm elections break. Landrieu is locked in a runoff with Republican Rep. Bill Cassidy. Mark Wilson/Getty Images hide caption

itoggle caption Mark Wilson/Getty Images

Beacon Power President and CEO Barry Brits, at the company's plant in Hazle Township, Pa. He says a loan from the Department of Energy made it possible for his company to develop its flywheel energy storage technology. Jeff Brady/NPR hide caption

itoggle caption Jeff Brady/NPR

Chinese President Xi Jinping and President Obama, seen here during a ceremony at the Great Hall of the People in Beijing, announced pledges to reduce greenhouse gases. HUANG JINGWEN/Xinhua /Landov hide caption

itoggle caption HUANG JINGWEN/Xinhua /Landov

Oil, carried here by the Trans-Alaska Pipeline, is fundamental to the state's economy. But Alaskans also face the effects of climate change in their daily lives. Al Grillo/AP hide caption

itoggle caption Al Grillo/AP

Chevron Corp. supported several candidates in Richmond, Calif., where the company has been hoping to modernize a large oil refinery, seen here in 2010. None of the Chevron-backed candidates were elected. Paul Sakuma/AP hide caption

itoggle caption Paul Sakuma/AP

One proposed solution for New England's energy price spike problem: Importing more liquefied natural gas and feeding it into the pipeline network on the other side of the region's bottleneck. Sam Evans-Brown/New Hampshire Public Radio hide caption

itoggle caption Sam Evans-Brown/New Hampshire Public Radio

Ray Gerrish repairs a drilling rig near Watford City, N.D. Oil industry analysts predict that oil prices will have to remain low for at least several months before having a significant effect on U.S. production. Jim Gehrz/MCT/Landov hide caption

itoggle caption Jim Gehrz/MCT/Landov