The trial involves ten trucks, both Scania and Volvo models, operating across Sweden from Luleå in the north to Skåne in the south. The aim is to evaluate how solar systems perform under varying climatic conditions and to measure their potential to improve energy efficiency in alternative-fuel fleets.
Each truck is equipped with Green Energy’s thin-film CIGS solar panels, which power onboard systems such as cooling units and tail lifts. By providing this auxiliary power, the panels are expected to reduce alternator load, fuel consumption and related emissions. Earlier deployments of the same technology in diesel fleets have shown 4–7% reductions in fuel use and CO₂ emissions, according to Green Energy.
The pilot includes 240 Wp solar systems on eight trucks – four running on HVO and four on LBG – and 320 Wp systems on two additional LBG-powered vehicles. The panels are connected to Green Energy’s charge controller and Fleet Tracker software, enabling real-time monitoring of energy generation and performance.
The company’s solar modules are ultra-light, fire-, weather- and shock-resistant, and designed to fit truck roofs without affecting aerodynamics. The systems have already been used by operators such as DFDS, DEKRA, Samat, Blaguss, FlixBus, PostNord, Girr Logistik and Arla.
“Already today we have reduced our greenhouse gas emissions thanks to electric and biofuel vehicles in our transport network. Now we are taking another step by piloting advanced solar panels together with Green Energy,” said Ylva Öhrnell, Sustainability Manager at DHL Freight Sweden.
“This pilot builds on proven results with diesel fleets. We’re excited to measure the impact of solar in improving fuel efficiency and reliability on DHL’s alternative fuel trucks,” added Anders Mikkelsen, Strategic Sales Manager at Green Energy.
Broader research highlights limits of solar integration
The SolarMoves project, a European research initiative analysing solar-equipped lorries across one million kilometres, recently reported that while onboard solar panels can reduce charging stops by up to 56%, their overall energy contribution remains small and economic returns poor for long-haul operators.
According to the study, solar panels on heavy-duty vehicles provided just 2–4% of total energy demand, with side-mounted panels performing considerably worse due to shading and limited exposure. High-mileage operations saw the lowest benefits, as long-distance trucks spend most of their operational hours in motion rather than parked in optimal sunlight.
Researchers noted that commercial vehicles spend 50–90% of their time stationary, often in loading areas or depots with significant shading, which further limits solar yield. While solar integration can meaningfully cut the number of charging stops for battery-electric vehicles, it has minimal impact on total cost of ownership or range for fleets covering 80,000–140,000 kilometres annually.
The study projected that widespread adoption could save 27 TWh of grid electricity by 2030 and reduce infrastructure investment by up to 25%, though these forecasts rely on behavioural and technological assumptions that remain unproven.
