US President Donald J. Trump told Republicans on June 6 that he envisions a 40 feet to 50 feet high wall encrusted with solar panels he called “beautiful structures.” After meeting with the president, Republican congressman Steve Scalise of Louisiana later told The Hill that Trump thought affixing solar panels to the wall would “ultimately pay for itself.” (In an unrelated event, Scalise was shot June 14 by a gunman while practicing baseball with fellow Republicans in Alexandria, Virginia, and reported to be in critical condition.)
Trump appears to have seized on a proposal submitted to the government by a small, Las Vegas-based construction-supply firm named Gleason Partners. The firm wants to construct a cement and steel wall stretching for more than 2,000 miles (3,200 km) along the US-Mexico border at a cost of about $7.5 million per mile. By outfitting the wall with solar panels, the firm proposes selling electricity on both sides of the border to pay construction costs within 20 years, reports the AP. “The wall pays for itself,” the firm’s founder Tom Gleason told E&E News.
To verify that claim, Quartz asked a company in the business of solar construction estimates to review the figures. Analysts at PowerScout, who have helped originate, develop and finance $750 million of new solar construction on more than 200 projects at previous firms such as SunEdison, used publicly available data to draw up project estimate budget (you can adjust the assumptions here).
PowerScout found electricity sales from a solar wall, under the most favorable assumptions, could pay for itself over 25 years — but you’d likely have to exclude the costs of operating or maintaining the array, building new transmission lines, acquiring land, and financing expenses. PowerScout also found the price tag of the proposed project was wildly underestimated: Gleason’s projected cost of $7.2 million per mile (about the same as a simple fence, according to government figures) was “virtually impossible to achieve with any set of assumptions.”
Estimates of the wall’s costs have varied. The Department of Homeland Security issued a $21.6 billion figure in February, while a Senate Democrats’ committee put the figure at $66.9 billion in April. Adding solar-panels to the structure would cost about $46 million per mile today (or somewhat less by 2020 if panel prices keep falling), PowerScout estimates. That puts total construction, at today’s prices, somewhere between $68 billion to $158 billion.
But solar panels are lucrative. In an optimistic scenario (and assuming transmission infrastructure which does not currently exist), PowerScout estimates that a solar wall on the southern US-Mexico border could generate about $169 billion in electricity over the expected 25-year life of the panels at today’s wholesale prices. That’s enough to power about 9.2 million homes (about 112,638 GWh per year). Of course, that much power coming online is likely to affect regional electricity markets, potentially reducing the price of electricity.
Quartz reached out to Gleason’s firm to review the estimates. It rejected PowerScout’s cost calculations arguing that those figures assumed huge margins and did not account for his company’s more efficient construction methods. “I am sure they did not have structural engineers review in detail our design,” said Tom Gleason. He said his company’s plan included “thin-film modules” and a moveable array to track the sun to increase solar generation. “Our wall is designed by experts and common sense,” he said.
Of course, if the goal is to build solar power, there are easier ways to do it. Gleason’s two-tiered structure would cost about 25% more than building a regular solar farm, estimates PowerScout, even without the wall. With all that cash allocated for a wall, one could simply build two more solar farms of equal capacity. Green groups, incensed by the potential wall’s ecological impact, have also rejected the idea that solar panels can redeem the proposal. “An ecological disaster with solar panels on top is still an ecological disaster,” Brett Hartl of the Center for Biodiversity said in a statement.