Marten Transport is betting on the power of the sun.

The company invested in solar energy to diminish its carbon footprint and eliminate needless costs.

"Solar panels have been installed on trucks to help maintain battery charge, resulting in saved [auxiliary power unit] run times and fuel savings," according to a website post from last October.

Besides equipping trucks with solar panels to power batteries during driver's down time versus running the engines, Marten also installed solar at all 14 of their terminals, Ashley Gray, sales project coordinator for Marten, said in an email.

Does this shine a light on a burgeoning trend in the trucking industry?

Who uses solar — and how

Solar power is a way to provide additional battery support for liftgates, telematics and refrigeration units in trailers, according to a 2018 report by the North American Council for Freight Efficiency. But it can also be used in terminals, offices and other facilities.

Rush Enterprises, a truck retailer, began construction of solar carports for its vehicles in 2019, Derrek Weaver, Rush's executive vice president, said in an email. The site became fully functional in June 2020, he said.

"Rush Enterprises is constantly looking for ways to reduce our energy consumption and solar power is [one] of the best ways for us to do that," Weaver said.

When representatives of Big Sun Solar, now Rush's solar provider, contacted Weaver's company about its community solar project, it became clear there was more than one potential benefit to the partnership.

"It seemed like a good opportunity for us to not only reduce our energy consumption but to also decrease the risk of hailstorms damaging our new vehicle inventory," Weaver said.

With 3,500 solar panels installed on six carports in the San Antonio, Texas, Trucking Center, Rush can protect up to 181 Class 8 commercial vehicles, said Weaver.

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"It seemed like a good opportunity for us to not only reduce our energy consumption but to also decrease the risk of hailstorms damaging our new vehicle inventory."

Derrek Weaver

Executive Vice President of Rush Enterprises

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Owner-operator Albert Transport in Laredo, Texas, tapped into solar power to keep its batteries charged in its tractors, according to NACFE's report. That created comfort for drivers, as the cab air conditioning continued to function for a longer period of time before the engine needed to be started while the driver waited at the dock.

Mesilla Valley Transportation with corporate headquarters in Las Cruces, New Mexico, was also mentioned in the report as a solar user. The trucking firm found it lessened the need for jumpstarts and service calls for trucks.

Groupe Robert, with offices in Montreal and Toronto, also mentioned in the confidence report, installed solar panels on the fairings and hoods of its trucks.

For tractors, the sun keeps the battery-powered heating, ventilation and air conditioning systems charged. It also helps support hotel loads during times the engine is off. On the trucks, the roof fairings provide access to sunlight if that area isn't already being used for branding or built-in skylights.

Xantrex manufactures thin, flexible solar panels to better fit the truck's curved surfaces. The Max Flex panel can also harvest up to 20% more of the sun's energy during the day, and in low-light conditions compared to a rigid solar panel, said Mitul Chandrani, spokesperson for the company in British Columbia, Canada.

"Lithium-ion batteries pack a lot of power in a small footprint and last six to 10 times longer than a regular battery and can be drained to 100%," said Chandrani. "Pair those with solar, and you can eliminate idling."

Fleets power up warehouses

For big fleets with their own warehouses, solar panels on the roof can make a lot of sense for helping to power the warehouse operation, said Kevin Otto, electrification technical lead for NACFE.

"But if you don't own the building, the process is much more complicated," Otto, who also co-authored Solar for Trucks and Trailers, said. "The owner of the building may not want to make that kind of investment for your trucking company when you might move at any time."

As an example of having ownership, Otto cited Frito-Lay's large truck facility in Modesto, California. There, the company has installed a big solar array in the parking lot to protect employees' cars as well as power the manufacturing operation on the same site. That makes sense when Modesto gets an average of 260 days of sunlight a year, he said.

That's key for fleets to consider, when it comes to using solar power. Locations of operation must receive enough sun to generate enough power. Calculators, such as the one from National Renewable Energy Laboratory, exist to help work through this consideration.

Key considerations for solar adoption

Of course, cost also figures into whether any new technology is worth it. But Weaver said after Rush was comfortable with the economics of the project, there weren't any internal barriers to implementing the solar carports. The company anticipates an ROI of about 150% over the 25-year lifetime of the solar panels, he added.

Currently Rush is working on multiple rooftop solar projects at dealerships around the country, Weaver said, and it has plans for more solar carports at some locations in California. This would be in connection with the installation of electrical vehicle charging infrastructure that's required to transition its own fleet to electric vehicles. The solar carports aren't directly connected to the electric vehicle charging infrastructure, but the carports will offset the additional electric use, he said.

"As of today, Big Sun Solar estimates that the solar generation from the panels we own has resulted in the elimination of 795,374 pounds of [carbon dioxide] since the system went active last year," said Weaver.

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"I think there's still confusion in terms of what solar really does."

Mitul Chandrani

Spokesperson, Xantrex

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As an industry, trucking is very slow to adopt emerging technology including solar tech, and some trucking industry individuals don't fully understand it, Chandrani said.

"I think there's still confusion in terms of what solar really does," he said. "Solar doesn't directly power anything — it's a charging source for the battery. It helps replenish batteries quickly thus extending the runtime of electronics and appliances."

But, as solar panels become more efficient and less costly, the adoption rate will go up. And when motor carriers are educated about the benefits of solar and the infrastructure needed for solar, they'll be able to make an informed decision about using solar in the fleets, he said.

"That means we, as suppliers and manufacturers, must play a key role in getting more fleets to adopt solar," said Chandrani. "I do believe lithium-ion storage and solar will gain momentum in the coming years."