Here, Patrick Loock, European Sales Director of Exel Composites, discusses the role composite materials play in proliferating electric buses, minimising weight and maximising fuel efficiency.
Government policies and investments are speeding up the evolution of zero-emission public transport.
China, the world leader in electric bus adoption, has supported the deployment of more than 500,000 e-buses through a combination of subsidies, local manufacturing incentives, and stringent emissions targets.
Financial incentives and pricing strategies are also encouraging greater public transport use. In the United States, New York’s Metropolitan Transportation Authority (MTA) has introduced the OMNY contactless payment system, which automatically caps weekly fares after a certain number of trips.
This system has made public transit more affordable and predictable for riders, while supporting efforts to expand zero-emission bus fleets in major US cities. Continued government support will be key to ensuring this trend is sustained.
The impact of composite materials on e-bus design
Early electric buses performed poorly in terms of range, only offering 100-170km per charge, while diesel buses ran for 575km.
However, advancements in battery technology, including improvements in energy density and charging speed, along with innovations in materials like composites, have improved operational efficiency.
In September 2023, VDL Bus & Coach’s new-generation electric ‘Citea’ travelled 310 miles in 24 hours in the "MaxiMile Challenge".
Composites play a crucial role in the construction of modern electric buses, whether it’s the roofs, body panels, side walls, skirt profiles, or luggage racks.
Their durability and performance reduce maintenance requirements and add longevity to the overall vehicle lifetime.
They can provide up to three times the tensile strength per unit weight, have low thermal conductivity, and a coefficient of thermal expansion of 0.1-0.5 x 10-6/°C, ensuring minimal dimensional change.
The ability to mould composites into complex shapes makes them ideal for bus construction. Advanced manufacturing techniques like pultrusion and continuous lamination enable the production of seamless parts. Composites side panel assembly, for example, is simplified by eliminating the need to join multiple metal panels.
Weight reduction plays a crucial role in e-bus design, as battery packs alone can add 1,350-2,300kg to a vehicle’s weight.
Composites are key to achieving this without compromising strength and resilience. For example, fiberglass strikes a balance between durability, lifespan, and structural integrity, with some products offering up to 20 percent weight reduction compared to aluminium.
Carbon fibre, with up to 40 percent weight reduction, is preferred for load-bearing applications, though it comes at a premium.
Meanwhile, hybrid composites combining different types of fibre offer a cost-effective alternative, reducing weight by 20 to 40 percent while providing aluminium-like stiffness.
Corrosion resistance and life cycle cost benefits of composites
Aside from weight savings, composite materials are extremely corrosion-resistant compared to metals.
Unlike steel, which requires coatings like hot-dip galvanising, composites eliminate the need for these kinds of treatments, reducing production costs.
They are thus ideal for public transport, where longevity and affordability are essential. Composites reduce maintenance and downtime, improving service availability.
Composite materials used in electric bus manufacturing improve efficiency, extend the lifespan of vehicles, and facilitate sustainability.
As demand for zero-emission public transport grows, the future of urban mobility will be shaped further by innovation in long-lasting, lightweight composites.
To learn more about how composites can be used in the transportation industry, click here.