The SolarMoves project tested vehicles across one million kilometres, finding that solar panels on heavy-duty vehicles contributed just 2-4% of energy needs. Side-mounted panels on delivery trucks generated only half the power of roof-mounted systems, with shading from loading bays significantly reducing performance.
Testing revealed that while solar integration can cut charging stops substantially, the technology showed minimal impact on total ownership costs for operators running high-mileage fleets.
ICE lorries dominate solar testing programme
The study equipped 18 vehicles with solar sensors, including Volvo FM Electric HGVs, Scania rigid trucks, DAF rigid lorries and DAF garbage vehicles. However, most commercial vehicles tested were conventional diesel lorries rather than electric lorries, limiting the relevance of findings for future electric freight operations.
Detailed monitoring of a Peugeot Boxer Luton van with three sensors revealed that directional travel significantly affects solar generation. Eastbound journeys produced different energy patterns compared to westbound routes, with panels facing away from the sun generating substantially less power.
Testing of DAF waste lorries equipped with five sensors – one on the roof and four on the sides – revealed the impact of operational parking behaviour. Commercial vehicles spend 50-90% of time stationary, typically at loading and unloading locations surrounded by buildings that create significant shading.
“It is extremely difficult to make an accurate prediction of the actual irradiance on the vehicles at a specific point along the route,” researchers acknowledged, noting that docking locations for freight operations rarely offer sunny parking options.
High-mileage operations see minimal benefit
The study categorised HGVs operations by annual mileage: 45,000km, 80,000km and 140,000km per year. Higher-mileage long-haul operations showed the poorest solar contribution rates, with tractor-trailers for regional and long-haul freight seeing minimal energy offset from integrated panels.
Energy consumption validation using a Volvo FM Electric lorry showed the researchers’ model underestimated actual consumption by 5%, suggesting real-world efficiency may be worse than projected.
27 TWh grid savings projection relies on unproven assumptions
Based on the limited data, researchers projected that widespread adoption could reduce EU grid electricity demand by 27 terawatt hours by 2030 and cut infrastructure investments by 20-25%. These projections depend on user behaviour changes and technology adoption rates that remain unproven.
The project plans to continue data collection through 2025, expanding into southern and eastern Europe to address geographical bias. However, fundamental economic barriers to adoption appear to persist for commercial operators.
