Washington (CNN) President Donald Trump renewed his war on windmills Saturday when he took aim at the technology for, among other things, killing bald eagles and threatening the property values of houses near the mills.

"You know, I know windmills very much. I've studied it better than anybody I know," Trump told a gathering of young conservatives in West Palm Beach, Florida, over the weekend.

Blasting some Democrats' support for his least-favorite form of energy production, Trump claimed the process for manufacturing windmills in some countries creates air pollution for the entire planet.

"It's very expensive. They're made in China and Germany mostly -- very few made here, almost none. But they're manufactured tremendous -- if you're into this -- tremendous fumes. Gases are spewing into the atmosphere. You know we have a world, right? So the world is tiny compared to the universe," the President said at the Turning Point USA conference. "You talk about the carbon footprint -- fumes are spewing into the air. Right? Spewing. Whether it's in China, Germany, it's going into the air. It's our air, their air, everything -- right?"

Trump has complained about windmills throughout his presidency, slamming the technology everywhere from the G7 conference in France this year to a Republican fundraising dinner speech that he used to claim windmill noise causes cancer. Scientific studies have not identified any human health risk.

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