President Donald Trump may have found a place where he can embrace renewable energy: on his proposed border wall.

Less than a week after pulling the U.S. out of the Paris climate agreement, Trump told congressional leaders he is exploring the idea of attaching solar panels to a wall he wants to build along the southern border, House Majority Leader Kevin McCarthy and House Majority Whip Steve Scalise confirmed to reporters.

“He did talk about it,” McCarthy said Tuesday night.

Asked about reports Trump said the wall would be 50 feet tall, McCarthy said, “They said there was — that they’ve been studying it, they have different people coming in. So it could be at different heights.”

Building a wall along the U.S.-Mexico border was a staple of Trump rallies throughout the 2016 campaign.

A congressional appropriation would still be needed to fund the initial construction, “but it also through authorizing and appropriation wouldn’t cost as much by producing energy at the same time,” McCarthy said.

Scalise said Trump has been looking at a lot of options on how to build the border wall and that the solar panels is among the options he’s reviewed.

“This is a new option that he’s been looking at that sounds like it’s got real promise,” he said. “I’m glad that he continues to explore more ways to make sure that the wall can get done and help secure our border.”

The idea is “still in the early stages of development,” Scalise said when asked how it would impact the congressional appropriations process. On height of the wall, he said, “That’s all going to be worked out.”