President Donald Trump wants to deliver on one of the central promises of his campaign — building a wall on the Mexican border.

He pitched Republican leaders on June 6 on a proposal to cover the wall with solar panels and use the electricity generated to cover the costs of construction and maintenance.

Trump mentioned the hypothetical solar wall during a rally in Cedar Rapids, Iowa, on Wednesday night, saying "this way, Mexico will have to pay much less money," as his supporters applauded.

Thomas Gleason is the managing partner of Gleason Partners LLC, a Las Vegas-based architecture firm that submitted a proposal to the Department of Homeland Security that included solar panels. He told Business Insider earlier this month that he had been batting around the idea of building a solar-paneled wall along the US-Mexico border "for months."

Gleason, being in the construction business, said he knew a few people in contact with Trump, so he directed his firm to come up with a design and "get it in front" of the president after the DHS requested proposals.

The wall would generate enough power to pay for its construction in under 20 years, Gleason claimed. But he cautioned that numerous variables — the Mexican border is far from a straight line and light intensity changes from month-to-month — could complicate his calculations. He said his firm hasn't received the go-ahead from the federal government to conduct a full evaluation.

Gleason said his estimate is predicated on the cost of manufacturing solar panels decreasing over time. The price of installing solar panels has dropped from around $8 per watt in 2009 to $1.50 per watt in 2016, according to the Solar Energy Industries Association.

Business leaders within the renewable-energy sector commended Trump's decision to seriously consider going solar.

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Gleason said he believes that farmers on both sides of the border would appreciate the wall, as the energy output would create a "microgrid" that could provide cheap power to remote areas on the border underserved by energy utilities.

"We'd be our own utility," Gleason added, though he said third-party contractors would need to actively manage the wall, per the DHS's request. He said the cheap, renewable electricity produced by the wall should "mitigate" political resistance over time, and increase property values along the border.

Gleason also said the panels sourced by his firm would be manufactured in the US, whereas a concrete wall would entail shipping "truckloads" of concrete from Mexico, along with the higher maintenance costs.

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Here are some renderings of what the wall could look like, which Gleason's firm provided to Business Insider:

The panels on the proposed wall would be offset to avoid casting shadows, as solar panels are usually installed on roofs, not walls. The panels on the roof would move to track the sun.

This is the proposed Mexico side of the wall. Solar panels in the US generally face south to maximize sunlight.

Another cross-section of the Mexico side of the wall. The panels would be set on a concrete foundation, with fencing above and below the panels.

The US side of the wall. Gleason says the wall would generate enough electricity to pay for sensors and border patrol stations along its length.

Here's a close-up of the solar panels, which would be manufactured in the US, Gleason said. He said they would generate 2.0MWp per hour of electricity.