As the world shifts towards cleaner and more sustainable mobility, the transport industry plays a crucial role in reducing carbon emissions. To achieve climate goals and reduce air pollution, public authorities (primarily in Europe but also in Asia) are accelerating projects to restrict the number of vehicles with internal combustion engine (ICE) in circulation and replace them with zero-emission ones.
According to OICA, there are 1.9 billion vehicles in use globally. Since it is not possible and economically viable for all of them to be replaced by new electric cars, retrofitting is emerging as a cost-effective solution (esp. retrofitting of heavy-duty vehicles) that could accelerate the energy transition and reduce our carbon footprint. Retrofitting is a mechanical operation where the petrol/diesel engine and fuel tank are removed and replaced with an electric motor and battery, or a hydrogen fuel cell.
In recent years, multiple startups and innovative companies have emerged, offering tailored solutions to retrofit existing buses, trucks, and vans. According to North American firm Precedence Research, the global automotive retrofit electric vehicle powertrain market size accounted for USD 65.94 billion in 2024, and is predicted to surpass around USD 144.61 billion by 2034.
Substituting a traditional powertrain running on fossil energy with a powertrain with no tailpipe emissions provides immediate benefits in terms of air quality, and long-term benefit for the environment and climate. It extends the service life of the existing fleet, reducing both waste and carbon emissions from the manufacturing of new vehicles.
In France, where the national energy and environment agency ADEME estimated that electric retrofitting would reduce greenhouse gas emissions by between 61 and 87% compared with diesel, the government launched a national action plan in aid of retrofitting, providing approximately 100 million euros to decarbonize transport.
Furthermore, retrofitting is mentioned in the European Commission's industry action plan for the automotive sector and it will be particularly relevant for low- and middle-income countries that are importing ever growing amounts of used ICE vehicles and that need to accelerate the decarbonization of their vehicle fleets.
While hydrogen-powered vehicles are still in the early stages of deployment compared to those powered by electric batteries, their future could be promising if green hydrogen (H2) prices decline as projected. A price of 5 to 7 euros per kg of H2 is considered a critical threshold.
Against this background, the UNECE World Forum for Harmonization of Vehicle Regulations (WP.29) and its Working Party on Pollution and Energy (GRPE) has launched a new informal working group to develop globally harmonized provisions for electric vehicle and hydrogen fuel cell retrofit systems. Such harmonized regulatory framework would ensure minimum requirements for retrofit systems, provide robust performance requirements for converted vehicles and support the deployment of retrofit systems that could be installed on many vehicles in the countries that adopt the developed requirements.
Activities undertaken by the new informal working group will focus on all vehicle categories, from two- and three-wheelers to heavy duty vehicles, with initial emphasis on technological readiness and economic viability. This work is led by France and Spain, with support from Sweden, Germany, UK, Japan and the European Commission.
The new UNECE informal working group is expected to deliver on harmonized requirements for targeted vehicle categories and powertrain types by 2027.
