Biomethane in Brazilian light commercial vehicles: a case study in performance, emissions, GT-SUITE simulations and life cycle assessment

Biomethane is a renewable alternative to natural gas with strong potential to reduce greenhouse gas emissions in transportation. This study evaluates its application in Brazilian light commercial vehicles through experimental testing, GT-SUITE simulation, and life cycle assessment (LCA). A spark-ignition engine running on compressed natural gas (CNG) was experimentally tested, and a validated GT-SUITE model was used to simulate engine performance and emissions with biomethane. Engine maps for CNG were generated experimentally, while biomethane maps were obtained numerically. GT-Drive simulations assessed vehicle performance under real driving conditions. A well-to-wheel LCA compared biomethane and CNG in terms of emissions per kilometer traveled. Results showed that biomethane can replace CNG without significant losses in power or torque. However, a slight reduction in thermal efficiency and a 10.3 % increase in fuel consumption were observed on the FTP75 driving cycle. Average tailpipe emissions during the driving cycle remained similar due to the use of a three-way catalyst. From an environmental standpoint, biomethane achieved up to 81.5 % lower global warming potential and 75.5 % less particulate matter formation compared to CNG. However, photochemical oxidant formation increased by 70.2 %. Overall, biomethane proves to be a viable and environmentally advantageous substitute for CNG in light commercial vehicles, especially in reducing greenhouse gas emissions and promoting sustainable transport solutions. • Biomethane can feasibly replace CNG in Brazil's light transport sector. • GT-Suite simulations showed no significant impact on engine performance with biomethane. • GT-Drive simulation showed 10.3 % increase in fuel consumption for biomethane on the FTP75 cycle. • Biomethane use can reduce Climate Change potential by 81.5 % when compared to CNG. • Biomethane lowers particulate matter but increases photochemical oxidant formation.