A Shiny Border Wall That Pays for Itself

Forget a traditional barrier and build a 2,000 mile solar field along the border.


Mexican President Enrique Peña Nieto at a conference in Mexico City, Feb. 14.

Mexican President Enrique Peña Nieto at a conference in Mexico City, Feb. 14. PHOTO: REUTERS

Resolving the political impasse between Mexico and the U.S. over a border wall requires innovative thinking. How about this: Presidents Donald Trump and Enrique Peña Nieto should work together to construct a “solar wall”—a massive string of photovoltaic panels—on the Mexican side of the border. Building on our previous research, Homero Aridjis and James Ramey proposed the idea late last year. After studying the concept, we have concluded that the idea is not only technically and economically feasible, it might even be more practical than a traditional wall.

Why build in Mexico? Lower costs south of the border would greatly reduce the overall price tag. We estimate that building a roughly 2,000-mile-long single-row solar wall would cost less than $1 billion, plus site preparation costs such as fencing and road construction. Compare that with Mr. Trump’s wall, which could cost tens of billions of dollars.

Mexico’s solar-power potential also ranks among the highest on the planet. As Messrs. Aridjis and Ramey point out, its high central plateau deserts have a “dry, unclouded, low-latitude and relatively cool climate” that is perfect for photovoltaics. We calculate that one string of solar panels would have a power capacity of 0.8 gigawatts and could produce about 2,000 gigawatt-hours of electricity a year. Add three rows in parallel, and that would cost $3 billion while producing some 8,000 gigawatt-hours annually. 

That’s enough energy to power about half a million homes in the U.S.—or far more in Mexico. Some of these costs could be offset by private investors, who would have a strong incentive to partake in what would be a wildly profitable venture. Property owners along the border could also see new streams of income.

The project would present some difficulties for engineers. Normally solar fields are built in multi-row arrays, which form a rectangle. This would require long, skinny arrays that would be less efficient. But such technical challenges aren’t insurmountable.

Could such a wall secure the border? People can bypass any kind of border, whether it is constructed of concrete or solar panels, and this would not be a fortress-like barrier to illegal entry. Yet a solar wall would place more people, surveillance and physical infrastructure at what is now a largely deserted, lawless and dangerous part of North America. And unlike the monolithic wall Mr. Trump is proposing, it would be a beautiful structure. The burden of protecting the solar wall could be split between federal security forces and private power companies.

Regarding politics: Even without buy-in from Mr. Trump, the Mexican president could pursue this wall on his own territory, with financing from private investors. This would put a positive spin on Mr. Trump’s idea of a structure to divide the two countries. Mr. Peña Nieto could invite his northern neighbors to take part in the initiative, or Mexico could simply reap the financial and environmental benefits for itself.

No doubt it would be better if Presidents Trump and Peña Nieto came together and embraced this creative governance idea. In taking advantage of the fact that America and Mexico share one planet and one sun, they could use this opportunity to create a wall that unites rather than divides.

Mr. Fthenakis is director of the Center for Life Cycle Analysis at Columbia University, where he is also a professor. Mr. Zweibel was director of the Solar Institute at George Washington University.


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