Ideas for solar energy in transportation: sustainable fleets on the Solbian agenda

Solar-powered transportation

In recent years, the focus on environmental sustainability and the adoption of renewable energy solutions has increased significantly. With the growing concern about climate change and the urgency to reduce greenhouse gas emissions, more and more companies and organisations are seeking out innovative ways to adopt clean and environmentally-friendly technologies. Within this context, solar energy in transportation is gaining ground as a promising and sustainable alternative.

Solbian, which since 2009 has produced highly efficient flexible solar panels widely used in the marine and mobility sectors, recognises the importance of a sustainable approach to the transport sector and is committed to developing innovative solutions to up the sustainability of fleets.

Here are some suggestions on how solar energy applied to transportation can become a reality in your own fleets and how Solbian is working towards this...

On the tractor unit

It is increasingly difficult to meet the energy needs of modern tractor units just with truck batteries due to the growing number of electronic devices on board that serve to increase driver comfort. Flexible solar panels used in solar energy transportation are designed for applications on curved surfaces and fit perfectly on the vehicle spoiler.

This installation, which will thus take up less space, has the main advantage of keeping the battery charged, avoiding deep discharges and voltage fluctuations that lead to having to replace this component even sooner.

The Confidence Report on Solar for Trucks (1) produced by the North American Council for Freight Efficiency (NACFE) in 2018 states that, thanks to the many battery manufacturers and experts interviewed to produce the report, battery life can be doubled with photovoltaics. 

Many of the fleets surveyed by NACFE have to replace their batteries about every two years, whilst tractor units generally complete their cycle after four years. The energy produced by photovoltaics can extend the life of the factory batteries to match that of the tractor unit, a saving that alone can more than repay the cost of the solar system. 

Photovoltaics can then supply energy to battery-operated HVAC systems and other auxiliary systems by extending their operating time, not only to allow these devices to last the night without draining the batteries but also to reduce the load on the alternator the next morning, thus saving fuel. The ability to use on-board heating, air conditioning and auxiliary services for extended periods also ensures greater comfort for the driver, an aspect that may seem secondary but which influences driver loyalty and potentially reduces the costs associated with driver recruitment, training and retention. 

Solbian developed such an installation for a historic transport company in northern Italy that wanted to equip three vehicles of its fleet with flexible solar panels.

On the spoiler of each vehicle, a Solbianflex SX 114 ALLinONE module with built-in MPPT charge controller, capable of raising the voltage to charge the battery pack (24 V and 200 Ah), was fitted using double-sided adhesive tape. 

Ideas for solar energy in transportation: tractor unitinfographic that explains the operation of the photovoltaic applied to a tractor unit

Thanks to the remote monitoring system that collects solar production data and battery charging conditions, typical daily trends in battery voltage and current produced by the solar system were analysed then fed into the battery.  

Daily trend of battery voltage and charging current due to the solar panel

Daily trend of battery voltage (blue) and charging current due to the solar panel (red). 

It is clear to see how the sun’s contribution can immediately bring the battery voltage back up in the morning, helping to maintain the charge during the day so that in the evening, one can enjoy an extended rest period without having to start the engine to avoid excessive discharges.

The advantages of such a configuration can thus be summarised as follows: longer-lasting batteries, lower fuel consumption, a reduced need to keep the engine running during stops and greater driver comfort.

On trailers

Trailers have the potential to make a real breakthrough in solar-powered transport, thanks to the large surface areas available and the fact that both the roof and sides can be exploited for photovoltaic applications, being true solar parks on the move. Over the years, trailers have evolved to have an increasing number of devices that require electricity, many of which can be supported by on-board photovoltaics. Possible uses include liftgates, telematics systems and refrigeration units but in the future, photovoltaics could also contribute to powering the propulsion of electric tractor units.

The additional energy provided by the solar system can supplement that produced by the alternator, again helping to keep the batteries in good condition and prolonging their life. A properly sized system can help power the refrigeration units and charge the batteries that manage other important services which must remain active even when the trailer is disconnected from the tractor unit.

Thanks to photovoltaics, GPS tracking systems can remain active at all times, an important advantage for fleets that need to manage the location of their vehicles.

Temperature monitoring systems in refrigerated trailers can also benefit from the energy produced by solar panels, remaining operational even when the trailer is not connected to the tractor.

The batteries that power the trailer liftgate can then rely on photovoltaics to ensure that they are always functional, regardless of how often the trailer is charged by the tractor unit. This can even reduce the need to keep the engine idling to operate the liftgate.

On refrigerated vans

Refrigerated vans with cooled isothermal boxes are used for short to medium journeys, with load capacities in the order of a few tens of cubic metres. The refrigeration units are powered by the vehicle engine or by connection to the mains. Especially in the transport of frozen food, for very short journeys for deliveries to restaurants, coffee shops and bathing establishments in the summer season, the frequent opening and closing of the doors requires the engine to be kept running, resulting in considerable consumption and pollution.

A photovoltaic system installed on the roof of such a vehicle allows the engine to be switched off between deliveries within the legal temperatures and results in significant fuel savings. 

On buses and coaches

As to buses and coaches, long-distance lines or coaches for occasional use are the best scenario in which to apply photovoltaics. As reported by the International Energy Agency in its report “State-of-the-Art and Expected Benefits of PV-Powered Vehicles”, in some of these vehicles and depending on weather conditions, season of the year and so on, the auxiliary load, particularly air conditioning, results in hybrid models in even higher consumption than the bus motion. In such cases, the electricity provided by photovoltaic systems would be valuable and harnessed instantaneously. In contrast, city buses present more difficult conditions for PV systems due, for example, to excessive shade that reduces the availability of solar energy on board.

In 2020, the German start-up FlixMobility, which heads the Flixbus brand, started a pilot project on some of its buses on the Dortmund-London route (2). In the test period, the data reported a saving of 1.7 litres of diesel for every 10 kilometres travelled. The system installed on board is entirely responsible for powering the USB ports and passenger sockets, air conditioning, Wi-Fi and the multimedia entertainment system on-board.

On cargo bikes

Solar panels can likewise be installed on two-wheeled vehicles, such as e-bikes and cargo bikes. Cargo bikes are designed not only to transport freight but also people and animals. Considering the limited space on these vehicles and the need to keep maintenance costs low, the integration of photovoltaic modules is important.

The installation of solar panels makes it possible to maintain a constant daily charge, avoiding voltage fluctuations and deep discharges that could cause damage to the battery or sudden interruptions during deliveries. By using solar energy, cargo bike drivers can thus avoid delivery delays and improve overall efficiency.

The flexible, lightweight and efficient solar panels produced by Solbian have proven to be an excellent choice for cargo bikes, leading to partnerships with companies such as Need The Globe and I-FEVS for the development of solar energy solutions.

Ideas for solar energy in transportation: sun rider cargo bikes

The SunRider cargo bike. Photo courtes of Need the Globe

One example of a solar cargo bike is SunRider, launched by the Dutch company Need The Globe. This bike is equipped with a load compartment capable of holding up to 150 kilograms of freight. The contribution of solar panels reduces charging times, grid dependency and maintenance costs. During journeys, the SunRider is recharged with solar energy, gaining up to 100 kilometres of additional range per day.

Ideas for solar energy in transportation: FEVS e-bike

The I-FEVS e-bike. Photo courtesy of I-FEVS

The e-bikes produced by I-FEVS, rather, can be used for different purposes, such as urban deliveries or daily commuting. The solar panels are integrated into the robust nanocrystalline steel structure of the e-bike, allowing the electric motor to be recharged while riding.

Why solar energy in transportation is key in the future of fleets

The big issue for the future of transport fleets today concerns the environment. With electric vehicles now seemingly destined to become the main form of transport for people and freight, the integration of photovoltaics is a natural, cost-effective and high-potential choice to renew the sector.

Solar energy in transportation represents an exceptional opportunity to reduce the environmental impact of vehicles and promote sustainable development. Solbian is committed to leading this transition to sustainable fleets by offering innovative and pioneering solutions in the field of flexible solar panels. With its commitment to quality and efficiency, Solbian is proving that solar energy in transportation is a tangible reality, able to play a significant role in creating a more sustainable future for the transport sector.

This and other applications are essential to get a complete picture of the effectiveness of solar panels for transport. For this reason, we have produced a comprehensive e-book edited directly by our engineers. Click below to have a copy sent direct to your email.


Flexible photovoltaic panels: Examples of application

State-of-the-art technology applied to road transport and other vehicles.


  1. https://nacfe.org/research/trailer-general/#solar-panels-trailer
  2. https://www.pv-magazine.com/2020/02/11/flixbus-fleet-tests-18-cigs-panels/

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