There are many things Donald Trump publicly hates: the media, Hillary Clinton, Robert Mueller’s probe, and even Meryl Streep.

But his hatred for windmills has been long and enduring, dating all the way back to 2006, when they interfered with his plans for a golf course on the Scottish coast. At the National Republican Congressional Committee fundraiser dinner Tuesday, the president floated his latest conspiracy theory about the renewable energy turbine, claiming its large metal structure decreases surrounding property values and its “noise” causes cancer.

“If you have a windmill anywhere near your house, congratulations, your house just went down 75 percent in value. And they say the noise causes cancer. You tell me that one, okay? Rerrrr rerrrr!” he said during his speech at the annual spring dinner, without offering any evidence to support the claim.

According to The Atlantic, anti-wind power groups have previously erroneously claimed that the low-frequency noises from windmills can cause health problems including nausea, sleep loss, and anxiety. The Daily Beast could not find any study or report with evidence that the noise correlates to the development of cancer.

Trump’s wind-power dig was part of a larger attack on his 2016 presidential opponent, Hillary Clinton, who campaigned to increase investments in wind turbine investments and other renewable energy sources to combat fossil fuels and carbon emissions.

“Hillary wanted to put up wind. Wind,” he said.

Trump’s Tuesday night attack on wind power is hardly a new strategy for the president, but an escalation of his long hate-affair with windmills.

His feud with wind power started in 2006, when Trump was developing plans to build a golf course in Balmedie, Scotland, just as a renewable energy group was developing a multimillion-dollar offshore wind farm close by. The idea of windmills spoiling the view on his golf course put Trump on the offensive, and he threatened to pull out of the deal—a move that prompted more wind farm proposals and social in-fighting.

“With the reckless installation of these monsters, you will single-handedly have done more damage to Scotland than virtually any event in Scottish history,” Trump wrote in an angry letter to the Scottish first minister, according to previous reporting by The Daily Beast. “I have just authorized my staff to allocate a substantial amount of money to launch an international campaign to fight your plan to surround Scotland’s coast with many thousands of wind turbines.”

The golf course and resort eventually opened in July 2012 and ignited Trump’s hatred for the inanimate wind propellers.

Since joining Twitter, Trump has blamed wind turbines, known for effectively turning kinetic energy from wind into electricity, for killing birds (they do, but at a far lower rate than other energy sources), being “ugly” structures that “ruin the beauty of parts of the country” that “hurt tourism” and for leaving Americans without electricity when there is no wind.

All these reasons, according to the president, makes them “very, very sad!”

“It’s Friday. How many bald eagles did wind turbines kill today? They are an environmental & aesthetic disaster,” Trump tweeted in 2012, the first of over 30 tweets the president has devoted to wind power. The tweet also linked to a Canadian news article about environmental activists meeting with the finance minister to discuss the potential threat wind turbines pose to the habitat in the Gulf of St. Lawrence.

Later in 2012, Trump blamed China for “illegally dumping bird-killing wind turbines on our shores. Only one of many grievances—we should act,” despite any evidence suggesting the foreign country has installed the devices in the U.S.

The president reiterated this claim on Tuesday, calling windmills a “graveyard for birds.” “If you love birds, you never want to walk under a windmill, because it’s a sad, sad sight,” he said.

At a Michigan rally last month, Trump brought up his past with windmills and boasted that his tirade against the renewable energy source means he “knows a lot about wind.”

“If Hillary got in... you’d be doing wind. Windmills. Weeeee. And if it doesn’t blow, you can forget about television for that night, Trump said, bringing up his previous assertion that wind power is not efficient because it doesn’t work when the wind isn’t blowing.

“‘Darling, I want to watch television.’ ‘I’m sorry! The wind isn’t blowing.’ I know a lot about wind,” he added.

The president seemed to forget the battery-storage feature in the U.S. power grid that’s set up to handle such changes in the weather.