(CBS News) There was some big talk on energy Tuesday on the campaign trail. President Obama talked wind power and Mitt Romney said if he is elected, America will be so energy independent by the end of his second term that we'll no longer have to buy oil from the Middle East and Venezuela.
The president has talked about wind energy at every stop on this Iowa bus trip. Former Governor Romney focused on oil and coal. Both men are trying to draw attention to an issue that could sway the race in several battleground states -- energy.
At a wind farm in Haverhill, Iowa, President Obama touted his support for a valuable tax break for wind producers, a break Romney opposes.
"He's called these sources of energy imaginary. His new running mate has called them a fad," Obama told the crowd.
Iowa is home to the nation's largest wind sector, employing 6,000-7,000 people and providing 20 percent of the state's energy.
So Republican leaders in Iowa were startled when the Romney campaign came out against renewing the tax credit when it expires later this year.
Republican Senator Charles Grassley said: "I felt it was just like a knife in my back."
Obama argues Ryan is working against farmers
The White House sees this as a winning issue.
"I want to stop giving $4 billion in taxpayer subsidies that are going to oil companies that are making huge profits and have been subsidized for a hundred years and let's keep on investing in the new homegrown energy that's creating jobs right here in Iowa," Obama said at a campaign stop.
The Romney campaign accuses Mr. Obama of favoring renewables at the expense of more proven energy sources -- like coal, which produces 45 percent of the nation's electricity.
"We have 250 years of coal. Why the heck wouldn't we use it?" Romney asked a crowd recently.
On Tuesday, Romney met with coal miners in Bealsville, Ohio, and said the administration's strict new emissions regulations, issued in March, are forcing plants to close because it's too expensive to retrofit them.
Romney made this ambitious promise about his energy plan: "By the end of my second term, I make this commitment: We will have North American energy independence. We won't have to buy oil from Venezuela and the Middle East. We're gonna be independent."
Experts say it's theoretically possible to wean the U.S. off dependence on Middle East oil in eight years, but only if production is boosted dramatically and demand drops significantly, too. Right now, many experts say former Governor Romney's plan doesn't focus on reducing that demand.