Independent European research has just confirmed something Green Energy Group customers have experienced firsthand. Solar on trucks works. It saves diesel. And the financial case is strong.
The SolarMoves project – an independent, EU-funded study led by TNO and Fraunhofer ISE – modelled 23 vehicle types and analysed data from 1.3 million kilometres of real-world driving across two climate zones in Europe. Its findings are significant for any fleet operator still asking whether the business case for solar on trucks holds up. It does.
What the research found
SolarMoves analysed total cost of ownership across every vehicle type in the study. For diesel trucks, it found five-year savings of up to €32,000 per vehicle and payback periods of around 12 months, depending on vehicle type, location and operating pattern.
The mechanism is simple. Solar panels charge the batteries that would otherwise be charged by the diesel engine through the alternator. Reducing that load on the engine saves diesel. No new infrastructure required. No dependency on charging networks.
Lenneke Slooff-Hoek, SolarMoves project manager at TNO, summarised it this way:
“Electrification alone is not enough. We need innovations that structurally reduce energy demand. VIPV is exactly that.”
What our customers have been telling us
Green Energy Group has installed roof-mounted solar systems on thousands of commercial vehicles across Europe. Trucks, buses, coaches and trailers – operating across Europe, the Middle East and the Americas.
We use our proprietary WiVA (Within Vehicle Analysis) methodology [EU patent pending] to document the impact of solar on fuel consumption. WiVA compares the same vehicle with and without solar activity over time. It isolates the impact of the solar system on fuel consumption from other operational variables in real-world conditions.
In January 2026, we published data covering more than 4.2 million kilometres of analysed real-world operations. The WiVA data showed average fuel savings of 500 to 1,000 litres of diesel per truck per year, depending on vehicle type and operating pattern. This gives a typical payback of 12 to 18 months.
Since then, our dataset has grown to over double this figure – and we will be publishing an update very soon. Follow us on LinkedIn or sign up to our newsletter to be the first to find out.
SolarMoves findings are in some cases more optimistic than our own data. But the conclusions are closely aligned. The savings are real, they are consistent, and the payback is fast.
It is significant to see a respected, independent body now documenting findings that align with what we have measured with our customers in real-world operation. That matters for the industry, for operators making investment decisions, and for the regulatory conversation that needs to follow.
Why this matters beyond the business case
The ultimate goal for heavy transport is zero-emission electric vehicles. But there is a 10 to 15 year transition period ahead in which diesel remains the dominant fuel. The charging infrastructure needed to support full electrification at scale is not yet there.
Solar on existing vehicles is available today and can be implemented at scale immediately. Across Europe, widespread adoption represents more than 40,000 barrels of oil per day* that would not need to be imported, burned or emitted.
*Based on Eurostat EU heavy-duty vehicle diesel consumption data (2023), ACEA fleet statistics, and Green Energy’s documented WiVA average saving rate.
The path to regulatory recognition
Research like SolarMoves builds more than a business case. It builds the independent evidence base needed to drive regulatory change.
The most important step is inclusion in VECTO – the EU tool used to certify heavy-duty vehicle emissions. Solar is not currently recognised in VECTO, which means manufacturers have no regulatory incentive to integrate it at the point of production. SolarMoves explicitly recommends this changes.
The Netherlands has already shown what a first policy step looks like, with subsidies for solar-equipped trailers already in place. More member states need to follow – and including VIPV in VECTO would give manufacturers a direct regulatory incentive to build solar-ready vehicles as standard, unlocking far greater adoption across the industry.
Find out what solar could mean for your fleet
The question now is not whether the business case exists. It does. The question is how quickly the savings car start for your fleet.
Curious how much fuel solar could save your fleet? Use our savings calculator to get a quick picture based on your vehicle type and operating pattern: https://greenenergy.pro/savings-calculator
If you are ready to take the next step, get in touch: https://greenenergy.pro/contact-green-energy
