The European Union’s promise to buy $750 billion of American energy imports over three years was pivotal to securing a trade deal with President Donald Trump, but it’s a pledge it will struggle to keep.

The European Union pledged to buy billions of dollars’ worth of energy resources from the United States. Experts say that’s unrealistic and could hurt Europe’s climate goals.

The EU has pledged to buy $750 billion of energy from the U.S. in exchange for a lower rate tariff rate in its trade deal, but analysts say this is unrealistic.