35 to 70 GW of solar, plus wind, could power all freight trucks in the U.S. or Europe

By Will Driscoll

Many truck manufacturers are developing electric freight trucks, whose projected lower costs for fuel and maintenance would, by one estimate, quickly outweigh their higher purchase price. With this cost advantage, electric trucks could ultimately dominate freight trucking. A charging infrastructure for an all-electric continent-wide fleet of freight trucks in the United States or in Europe could be powered by 35 to 70 gigawatts of solar farms, plus an equivalent amount of wind farms.

Tesla and Peterbilt are the first firms to develop electric heavy-freight trucks—the global term for tractor-trailers or Class 8 trucks. BYD already offers medium-sized electric trucks and a larger electric freight truck with a short range, while medium-sized electric trucks have been announced by Daimler, Cummins, Volvo, DAF, and a Navistar/Volkswagen joint venture.

The North American Council on Freight Efficiency predicts that electric trucks will have an “increasing role” in freight transportation. Also relevant—because freight trucks, like city buses, operate many hours per day—is a projection by Bloomberg New Energy Finance that electric city buses will capture 84 percent of global bus sales by 2030, due to low operating costs and declining battery costs.

In the policy arena, a report from the International Council on Clean Transportation, which supports national governments in reducing transport sector pollution, notes that “electric-drive heavy-duty vehicle technologies are essential to fully decarbonize the transport sector.”

These market and policy drivers point to a new market opening for solar power: solar farms, possibly near truck stops, to power electric freight trucks. A spreadsheet calculation shows that 35 to 70 gigawatts of solar power, plus an equivalent amount of wind power, would produce an amount of electricity each year equal to the needs of an all-electric fleet of heavy-freight trucks in the U.S. or in Europe. That’s because by coincidence, the fleets of heavy-freight trucks in the U.S. and Europe travel approximately the same distance each year. (A technical note below provides details of the calculation.)

Pursuing this market opening could help the solar industry maintain its approximate 30 percent global growth rate in recent years, even as the industry keeps expanding. Maintaining a 29% growth rate, deemed “challenging but feasible” in a research studypublished in Science magazine, would result in a global installed base of 10 terawatts of solar power by 2030.

As electric freight trucks become more widely available, solar industry participants could help ensure that charging stations for the trucks are solar-ready, and ultimately solar-powered. This could involve research and decisions regarding optimal placement of charging stations; ensuring that a sufficient number of charging stations is always available to meet growing demand; possibly optimizing charging during times of peak solar and wind production; and providing electricity storage as needed.

Powering electric heavy-freight trucks with solar and wind power would also cut CO2emissions by displacing diesel fuel. Globally, road transport accounts for 22% of energy consumption, of which 30% is long-haul road freight. Therefore, CO2reductions of about 7% (i.e., 30% of 22%) could be achieved by powering heavy-freight trucks with renewable energy, in each region that follows this path.

If most trucking firms ultimately conclude that electric heavy-freight trucks save money, they could aim to replace their diesel trucks with electric trucks as their diesel units reach the end of their useful life. The Bloomberg projection noted above projects that will happen for electric city bus sales by 2030. With global production of heavy-freight trucks estimated by Deloitte at 1.7 million in 2014, the pace of diesel truck replacements could be limited by global manufacturing capacity for electric heavy-freight trucks.

Technical note: The calculation starts with the annual distance traveled by the current U.S. and European fleets of heavy-freight trucks in 2015, as reported by the International Energy Agency; each is approximately 200 billion kilometers. For the energy needed to power a heavy-freight truck, the lower bound analysis uses an estimate of one kilowatt-hour per mile, developed by University of California/Berkeley materials science professor Gerbrand Ceder. The upper bound analysis uses a specification that Tesla reported subsequently for its heavy-freight truck of “less than 2 kWh per mile” (the upper bound uses 2 kWh per mile). Converting kilometers to miles, and kilowatt-hours to gigawatt-hours, and then multiplying shows that 124,000 to 248,000 gigawatt-hours per year would power such a fleet in either the U.S. or Europe. At a U.S. national average capacity factor for a solar farm pegged at 20 percent by the National Renewable Energy Laboratory, 70 to 140 gigawatts of solar would produce this amount of electricity each year (given 8760 hours per year). If solar and wind each provided half the energy needed, solar’s contribution would be 35 to 70 gigawatts.

Sensitivity analysis: Regarding solar’s capacity factor in the U.S., Lawrence Berkeley National Laboratory has reported the median capacity factor for utility-scale solar to be 26 percent. If this were to be the average capacity factor for future utility-scale solar installations, rather than the 20 percent value used above, the solar capacity needed would be reduced accordingly.