Can Solar Panels Improve Commercial Vehicle Fuel Efficiency?
Yes, solar panels can help improve fuel efficiency in some commercial vehicle applications – but the scale of the benefit depends on what the solar system is designed to do.
Not every vehicle solar installation is primarily about saving fuel or reducing CO₂. For many fleets, particularly where solar is being used to maintain a 12V or 24V battery, the main benefits are improved battery health, greater fleet reliability and reduced battery-related downtime.
Where solar is supplying energy that would otherwise need to come from the vehicle’s engine, alternator or another power source, however, the opportunity for fuel and carbon savings can be much greater.
Battery Maintenance and Trickle Charging
Many of our commercial vehicle solar systems provide a controlled trickle charge to maintain battery charge and offset parasitic or operational electrical loads.
In these applications, the principal benefit is battery protection rather than fuel saving. Keeping the battery at a healthier state of charge can reduce deep discharge, help extend battery life and reduce the number of battery replacements required over the vehicle’s lifetime.
While the direct fuel and CO₂ savings from a small trickle-charge system may be relatively modest, there is also a wider environmental benefit. Extending battery life means fewer batteries need to be manufactured, transported and ultimately recycled or disposed of over the life of the vehicle.
For these applications, we believe the strongest case for solar is therefore its operational benefits – improved battery health, reliability and reduced downtime – rather than overstating potentially small or difficult-to-measure fuel savings.
Read more about how vehicle solar can help extend lead-acid battery life.
Read why carbon reduction isn’t always the primary reason for fitting solar to a commercial vehicle.
Reducing Engine Idling on ICE Vehicles
On internal combustion engine (ICE) vehicles, electrical equipment can place significant demand on the vehicle battery.
Where an engine would otherwise need to run or idle simply to replenish the battery or support electrical loads, solar can provide an alternative source of energy during daylight hours.
Reducing unnecessary engine idling can help reduce fuel consumption, emissions and engine running hours, making the potential fuel-saving benefit of solar more significant in these applications.
Supplementary and Autonomous Power
The opportunity for more direct fuel savings increases where larger solar systems provide supplementary or autonomous power to onboard equipment.
Solar can be used to support ancillary equipment that would otherwise take energy from the vehicle’s alternator or another power source. The greater the amount of energy displaced by solar, the greater the potential opportunity to reduce fuel consumption and associated CO₂ emissions.
Waste and recycling vehicles are a good example. Available roof space can be used for a larger solar array to generate energy for onboard ancillary equipment, reducing demand on the vehicle’s alternator and helping to reduce fuel consumption and emissions.
The actual saving will depend on factors including the vehicle, equipment power demand, operating cycle, available roof area and the amount of solar energy that can be generated.
Learn more about the difference between trickle charging, supplementary and autonomous solar power.
What About Electric Vehicles?
As fleets transition from internal combustion engines to electric vehicles, the conversation changes from fuel efficiency to energy efficiency.
Electric light commercial vehicles (eLCVs) still rely on a conventional 12V auxiliary battery to operate many critical vehicle systems. Our most common eLCV solar application uses available daylight to maintain this battery, helping to protect battery health, improve vehicle reliability and offset ongoing electrical loads.
More broadly, Vehicle-Integrated Photovoltaics (VIPV) can provide energy to support auxiliary batteries and onboard electrical equipment that would otherwise ultimately need to be replenished from the vehicle’s primary energy source.
Solar can therefore help preserve the energy available for the vehicle’s principal purpose – moving the vehicle – while reducing reliance on external or onboard energy sources for auxiliary electrical demand.
It Depends on the Application
Ultimately, there isn’t a single fuel-saving or carbon-reduction figure that applies to every commercial vehicle solar installation.
For a small battery-maintenance system, improved reliability, longer battery life and reduced downtime may deliver the greatest return. Where solar reduces engine idling or supports electrical equipment, fuel and emissions savings can become more significant. For larger supplementary or autonomous power systems, those savings may be greater again.
That’s why we assess each application individually, considering the vehicle, operating cycle, electrical demand and available installation area before recommending the most appropriate solution.
