The election-year row over the direction of US energy policy ratcheted up a notch yesterday, as President Obama and Republican challenger Mitt Romney set out competing visions for the future of America’s energy mix.

Speaking during a campaign tour of Iowa, Obama stressed his support for the burgeoning wind energy sector, drawing direct contrasts with Romney’s plans to cut support for the industry. Meanwhile, Romney used a trip to a coal mine in Ohio to slam the president for passing environmental regulations that he blamed for stifling domestic coal production.

Highlighting his plan to make clean energy a wedge issue for voters in the autumn, Obama stressed that the wind industry currently supports around 7,000 jobs in Iowa and provides a fifth of the state’s electricity.

He also criticised Romney for declaring that the benefits associated with alternative energy are “imaginary” and noted that the new Republican vice presidential candidate Paul Ryan has previously described wind energy as a “fad”.

Obama aimed a joke at Romney’s stance, detailing how his challenger had once argued that “you can’t drive a car with a windmill on it”.

“I don’t know if he’s actually tried that,” Obama said. “I know he’s had other things on this car.” The reference to the 1993 trip when Romney’s dog famously rode on the car roof in a carrier was followed by praise for a wind energy industry that the President hailed as a genuine success story.

“If he wants to learn something about wind, all he has got to do is pay attention to what you’ve been doing here in Iowa,” Obama said. “And if Governor Romney understood what you’ve been doing, he’d know that we used to have to import most of the parts that were used for wind turbines. They’re now being made here in America, by American workers in American factories. That’s not ‘imaginary’ – that’s real. That’s part of what we’re fighting for in this election.”

Obama also reiterated calls for Congress to immediately approve an extension of the wind energy production tax credit (PTC), which many within the industry regard as essential to its continued growth.

The Romney campaign has said it wants the tax credit to lapse, arguing that it supports wind energy, but wants to see it compete on a level playing field with other forms of energy.

But Democrats and the wind energy industry are warning the threat that the tax credit could end has already led to job losses and project delays. Critics have also noted that Romney’s desire to end energy industry tax breaks does not extend to incentives available to the oil and gas industry, which the Republican campaign has said it wants to see extended.

Obama’s comments came as the US Department of Energy released its annual Wind Technologies Market Report, revealing that just shy of a third of newly installed power capacity last year came from wind energy, leading to $14bn of investment.

Meanwhile, Romney used his trip to Ohio to reiterate his plan to make America energy independent within eight years through a huge increase in domestic coal, shale gas, and oil production.

He again accused the Obama administration of undermining the coal industry by burdening it with unnecessary regulations, which he blamed directly for job losses.

The Republican criticisms relate to a series of regulations from the Environmental Protection Agency that are designed to enhance efficiency at fossil fuel power plants and limit pollution from mining operations.