Shell's Nanuq was built especially for oil spill response cleanup in the Arctic Ocean. It can store 12,000 barrels of recovered oil. The 300-foot vessel is docked at Dutch Harbor, Alaska, for the winter. Jeff Brady/NPR hide caption

itoggle caption Jeff Brady/NPR

Several federal agencies are looking into the practices and policies around offshore oil drilling. In May, the Development Driller III platform (top) was surrounded by support vessels as it drilled a relief well at the site of the Deepwater Horizon oil spill in the Gulf of Mexico. Charlie Riedel/AP hide caption

itoggle caption Charlie Riedel/AP

Shirley and Kevin Leung own the Magic Rabbit Car Wash & Detail in Highlands Ranch, Colo., where they also sell gas. They say high oil prices are already hurting their bottom line. Jeff Brady/NPR hide caption

itoggle caption Jeff Brady/NPR

Democratic Sen. Michael Bennet of Colorado (left) and Republican challenger Ken Buck appear on NBC News' Meet the Press, on Oct. 17. William B. Plowman/NBC NewsWire via Getty Images hide caption

itoggle caption William B. Plowman/NBC NewsWire via Getty Images

Former Rep. Tom Tancredo, the Constitution Party candidate (left), Republican candidate Dan Maes (center), and Denver Mayor John Hickenlooper, a Democrat, at a television debate last month. Tancredo's presence in the race has split the Republican vote. Ed Andrieski/AP hide caption

itoggle caption Ed Andrieski/AP

The U.S. burned 138 billion gallons of gas last year. Currently, gasoline contains up to 10 percent ethanol. The ethanol industry wants to increase that to 15 percent, but the oil industry has raised concerns. Jeff Brady/NPR hide caption

itoggle caption Jeff Brady/NPR

The sun sets over an oil platform waiting to be towed out into the Gulf of Mexico at Port Fourchon in Louisiana. Getty Images hide caption

itoggle caption Getty Images

Terry Walter grows hay, wheat and corn and runs well over 2,000 cows on about 3,000 acres in Colorado. Barry Gutierrez for NPR hide caption

itoggle caption Barry Gutierrez for NPR

Sen. Michael Bennet (D-CO) visits with a young girl as he campaigns in downtown Colorado Springs, Colo., on Aug. 9. After surviving a tough primary challenge, Bennet is now in a close race with Tea-Party-backed Republican Ken Buck. Ed Andrieski/AP hide caption

itoggle caption Ed Andrieski/AP

A bad harvest and fires in Russia have caused U.S. wheat prices to jump nearly 50 percent in recent months. Bakeries and other businesses are facing higher costs. Spencer Platt/Getty Images North America hide caption

itoggle caption Spencer Platt/Getty Images North America

A wind turbine, generating power near Boston in 2006. Stephan Savoia/AP hide caption

itoggle caption Stephan Savoia/AP