OTAY MESA, Calif. – A solar-paneled barrier along the U.S.-Mexico border is an option the Trump administration could pursue, according to a senior Customs and Border Protection official who has been closely monitoring the construction of prototypes that are meant to inspire a design for President Trump's border wall.

Mario Villarreal, the newly appointed division chief for CBP's San Diego field office, is enjoying his front-row seat to history as President Trump's border wall continues to stir controversy 3,000 miles away in Washington.

Villarreal helps manage 2,200 front-line federal border patrol agents stationed at one of the busiest commercial ports of entry along the southern border of the U.S. But for the last four weeks, he has also kept a close eye on eight towering structures that are slowly being built behind San Diego's secondary border barrier, a steel mesh fence that spans 13 miles and was built during Bill Clinton's second term.

"We've had various types [of barriers] along the border for decades," Villarreal told the Washington Examiner in an interview Wednesday. "To finally partner with an industry to get their creativity and ideas, it's certainly refereshing."

Related: Trump's border wall prototypes already being tested by illegal immigrants

After reviewing hundreds of proposals, ranging from translucent plexiglass barriers to concrete walls with "talons," the Department of Homeland Security awarded eight contracts to six vendors last month to bring their border wall renderings to real life. Each vendor was given one month to construct a 30-foot prototype and a contract that could eventually reach $300 million, according to CBP spokesman Roger Maier, who said the six companies chosen "are only using about $450,000 each" to build their units.

"We're excited to see the industry come up with new, innovative, and creative ideas in the form of border wall prototypes," Villarreal told the Examiner.

One idea, floated by Trump earlier this summer, is a barrier along the border that "pays for itself" through the production of solar energy.

"We're certainly looking for different methods and ways to make this better. Solar panels or technology bundles on top of the fence certainly isn't off the table," said Villarreal, a 32-year veteran of CBP who has worked in three of the four states bordering Mexico.

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Installing solar panels along an updated border wall would be a huge moment for someone like Villarreal, who lit up as he described "the evolution of cellphones" from portable boxes agents used to have to lug around to, essentially, handheld computers with high-resolution cameras.

The current border wall stretching 60 miles across San Diego took four years to build and is made of surplus landing mats from the Vietnam era. At 10-feet tall in its highest areas, it is susceptible to even the most basic climber. Border patrol agents apprehended 31,891 unauthorized immigrants in San Diego alone last year, after they successfully crossed the city's "primary barrier."

"The corregated landing mat almost gives you a foothold to climb it," explained Ralph DeSio, a public affairs specialist for CBP. "People set up ramps, ladders, ropes, you name it."

The six companies chosen to build mock border walls in Otay Mesa have until Oct. 26 to put on finishing touches before each prototype undergoes a rigorous examination by CBP officials.

"The anti-climbing will be key, as well as the durability [and] sustainability of the prototypes," Villarreal said. "Personnel from U.S. Customs and Border Protection will certainly be key in evaluating and testing the prototypes."