Onboard solar has passed the point of proof: two European OEMs delivering SolarOnTop at scale

HANNOVER, 13 September 2026 — After a decade of development, with hundreds of systems in daily operations across eight countries, IM Efficiency's SolarOnTop is now being rolled out fleet-wide by major retailers and is now built into the production lines of Langendorf and Royal Burgers. With over 250 new SolarOnTop trailers hitting the road in 2026, onboard solar has moved from pilot to production.

Solar power on trucks and trailers is no longer an aftermarket retrofit solution. It is a proven, measured and now factory-fitted part of how European fleets run. That is the message Dutch technology company IM Efficiency brings to IAA Transportation 2026, backed by the largest factory-fit programme of onboard solar in Europe to date: 250 double-deck trailers fitted with SolarOnTop, built by Royal Burgers and Langendorf — part of the Wielton Group, Europe's third-largest semi-trailer manufacturer —and delivered to Action, one of Europe's largest non-food discount retailers, in 2026 alone.

The rollout is not an isolated case. Fleets in the Netherlands, Poland and Italy are now specifying solar at the point of purchase, with Royal Burgers and Langendorf, two of Europe's specialists in double-deck trailers, having integrated it into their production lines. This marks a significant change in how transport companies equip their fleets with auxiliary power. It is driven by a straightforward operational reality: trailers need energy. And SolarMoves — the EU-funded research programme led by TNO with Fraunhofer ISE, Lightyear, Sono Motors and IM Efficiency — measured the same fuel savings across 1.3 million kilometres. Its final report was published in May 2026.

The technology is already being adopted at scale. Besides the 250 trailers fitted with SolarOnTop for Action in 2026, onboard solar is becoming the default energy source for other customers of Royal Burgers and Langendorf, such as Rossmann in Poland and Esselunga in Italy. Systems are also in service outside Europe, including with a major retail fleet in Chile.

IM Efficiency has developed solar energy systems for heavy-duty vehicles since 2014, and holds one of the longest continuous real-world datasets in the sector. Its SolarOnTop platform, with solar modules, intelligent power electronics, and a cloud platform, all developed in-house, has accumulated over 50 million kilometres of real-world data across 35 fleets and every kind of duty cycle: retail distribution, long-haul, temperature-controlled and agricultural transport.

The results are consistent. Trailers that generate their own energy do not run out of it. Tail lifts, pallet trucks, lighting and telematics stay powered through continuous loading cycles without the truck engine idling. Batteries last longer and fuel consumption and CO₂ emissions per truck-trailer combination drop by 5%.

Action's own trial with eight trailers confirmed the pattern: no more power-related breakdowns, batteries fully charged through the loading cycle, longer battery and tail-lift life, fewer maintenance interventions and quieter, idle-free loading.

What has changed in 2026 is scale. Fleet operators are no longer testing solar on a handful of vehicles; they are specifying it across entire trailer orders. Royal Burgers and Langendorf, both early adopters of SolarOnTop, now integrate the system on the production line so that every trailer arrives with its energy system installed and commissioned.

Three forces are converging. Trailers carry more electrical equipment every year (e.g. tail lifts, pallet trucks, fork lifts, moving floors, telematics, sensors, refrigeration) and that energy has to come from somewhere. Diesel prices and CO₂ taxation make every idling hour and every kilowatt-hour generated by the engine more expensive. And the transition to electric trucks makes onboard generation more valuable, not less: every kilowatt-hour produced on the roof is range that does not have to come from a charger.

Regulation is beginning to catch up, but onboard generation is not yet recognised in VECTO, the EU tool used to certify heavy-duty vehicle CO₂ emissions. A manufacturer that builds a vehicle capable of producing its own energy receives no credit for it, which removes the regulatory incentive to fit solar at the point of production. The SolarMoves final report explicitly recommends this changes.

At IAA Transportation (Hannover, 15–20 September, Hall 27 / Stand A31) IM Efficiency presents the next generation of SolarOnTop, extending the platform to refrigeration and hydraulic appliances and launching an open data interface that feeds energy, reliability and usage data into the fleet's existing telematics environment, alongside IM Efficiency's own dashboard.