NEWTON, Iowa (AP) — President Barack Obama, standing Wednesday in the shell of a once-giant Maytag appliance factory that now houses a wind energy company, declared that a “new era of energy exploration in America” would be a crucial to leading the nation out of an economic crisis. With pieces of wind turbine towers as a backdrop, Obama touted the small manufacturing firm as a success and as a step toward reducing the United States’ reliance on polluting fuels. But as the president on Earth Day set a goal for wind to generate as much as 20 percent of the U.S. electricity demand by 2030, legislation to make that a reality faced a challenge back in Washington in the Democratic-led Congress.