MEASURING SOLAR IMPACT ON FUEL USE
Proven solar savings.
Independently confirmed.
Solar power on commercial vehicles has been on the road for several years,
with fleet operators consistently reporting strong fuel savings.
It’s still a young technology and as yet, there’s no established industry standard
for proving what it delivers.
At Green Energy, we understand that reliable data you can trust is critical
for operators making budgeting and business decisions.
That’s why we developed the WiVA methodology.
To measure and determine the impact of solar energy on fuel consumption in heavy vehicles.
The WiVA dataset is now the largest of its kind for commercial transport in the world.
ISOLATING SOLAR'S IMPACT
The measurement challenge with A/B testing
Fuel consumption is affected by many factors – payload, speed, idling, driver behaviour, and vehicle maintenance. Fuel use between seemingly identical trucks can vary by more than 20%.
Traditional A/B testing tells you one truck used less fuel than the other. It can’t tell you why. That makes it unreliable for identifying the impact of any single factor – including solar.
That’s why Green Energy developed WiVA.
Traditional A/B testing tells you one truck used less fuel than the other. It can’t tell you why. That makes it unreliable for identifying the impact of any single factor – including solar.
That’s why Green Energy developed WiVA.
WiVA METHODOLOGY
How WiVA measures solar
impact on fuel efficiency
WiVA (Within Vehicle Analysis) solves the measurement challenge by comparing each vehicle to itself. It compares fuel use continuously against solar output on the same vehicle using WiVA.
First, we collect and organise telematics and solar production data from the vehicle. We then control for every major factor that influences fuel use – effectively isolating and quantifying the specific impact of solar energy on fuel consumption, with a 95% confidence interval. That result then undergoes a series of robustness tests to validate it.
Green Energy’s WiVA methodology is EU patent pending (EP 26173638.3).
First, we collect and organise telematics and solar production data from the vehicle. We then control for every major factor that influences fuel use – effectively isolating and quantifying the specific impact of solar energy on fuel consumption, with a 95% confidence interval. That result then undergoes a series of robustness tests to validate it.
Green Energy’s WiVA methodology is EU patent pending (EP 26173638.3).
INDEPENDENT RESEARCH
Independent third-party confirmation
DTU – the Technical University of Denmark – has independently evaluated the statistical model behind WiVA. They tested the model on two years of real data from 20 Volvo and Scania trucks, covering 3.2 million km of real-world driving. They confirmed:
DTU is the top-ranked technical university in the Nordics, ranked in the world’s top 50 for engineering, and part of the EuroTech alliance alongside TU Munich and EPFL.
- the two-way fixed-effects model to be the most appropriate for measuring the effect of solar energy on fuel consumption.
- a clear and statistically significant reduction in diesel use from solar on the specified dataset, with a 95% confidence interval.
- The solidity of the results through a series of rigorous robustness tests.
DTU is the top-ranked technical university in the Nordics, ranked in the world’s top 50 for engineering, and part of the EuroTech alliance alongside TU Munich and EPFL.
WORLD'S LARGEST SOLAR DATASET FOR TRANSPORT
10 million km of real-world results
We have used WiVA to measure the impact of our solar systems on more than 10 million kilometres, 130-plus vehicles, and over 1,000 vehicle months – more than three times the scale of DTU’s reviewed sample and the largest dataset for solar on transport in the world.
Different vehicle types, with different operating profiles, in different climates, driving different routes from northern Sweden to southern Spain – all showed positive fuel and CO₂ savings.
Average annual fuel savings ranged between 646 and 847 litres per truck, with annual CO₂ reductions of 1.7 to 2.3 tonnes. For buses, annual fuel savings ranged from 1,616 to 2,052 litres, with CO₂ reductions of 4.3 to 5.5 tonnes per bus.
Different vehicle types, with different operating profiles, in different climates, driving different routes from northern Sweden to southern Spain – all showed positive fuel and CO₂ savings.
Average annual fuel savings ranged between 646 and 847 litres per truck, with annual CO₂ reductions of 1.7 to 2.3 tonnes. For buses, annual fuel savings ranged from 1,616 to 2,052 litres, with CO₂ reductions of 4.3 to 5.5 tonnes per bus.
EU RESEARCH
Backed by EU-funded research
SolarMoves – a recent EU-funded, three-year research study on solar for transport by TNO and Fraunhofer ISE – provides further independent evidence that vehicle-mounted solar delivers real energy savings.
SOLAR ON THE ROAD
Trusted by operators worldwide
Over 3,000 commercial vehicles globally are already running on Green Energy solar. From fuel savings to battery benefits and lower emissions – read how road fleets are putting solar to work.
DATA-DRIVEN DECISIONS
The business case for solar has never been stronger.
When you receive a WiVA report or review fuel savings data from Green Energy, you can have confidence that the analytics and results are built on a methodology that has been documented – and reviewed, tested, and confirmed by a leading independent research institution.
