Republican presidential front-runner Donald Trump told an Iowa crowd Thursday that he is in favor of federal subsidies for wind energy.

During a voter forum in Newton, Iowa, Trump said he's "OK" with wind energy subsidies, mostly because the price of oil has plummeted during the past year. With oil costing so little, there's not much incentive to build windmills to generate wind energy without subsidies, Trump said.

"It needs subsidy, otherwise they're not going to get built," he said. "They're very expensive to build and they're very expensive to maintain."

The Wind Production Tax Credit expired at the end of last year for new projects, but has been the subject of debate during the ensuing months.

Proponents want to see the subsidy program renewed to stimulate business and continue a period of intense growth in the wind energy sector, while opponents argue wind energy has become mature and doesn't need more federal subsidies.

According to the American Wind Energy Association, Iowa ranks third in the country for installed wind energy capacity. About 28.5 percent of the state's power comes from wind energy, accounting for about 1.5 million homes.

According to the association, about $10 billion has been invested in wind energy projects in Iowa and the industry accounted for up to 7,000 jobs in 2014.

Trump said there are some problems with wind.

"It's an amazing thing when you think they can, out of nowhere, out of the wind, they make energy," said Trump, currently fourth in the Washington Examiner's presidential power rankings. "But, it's a problem. They're very expensive to build and without it I don't think they work without subsidy, which is a problem because when you need subsidy it's a problem."

Trump added he's not a big fan of federal subsidies in general and said wind energy has a strong lobbying group that kept the tax credit intact.