Life cycle assessment of a partially renewable blend for bi-fuel passenger cars and comparison with petrol and battery electric cars

Abstract

This study assesses the environmental impacts of the life cycle of B- and C-segment passenger cars fuelled by a blend of liquefied petroleum gas (LPG) (60% m/m), bio-LPG (20% m/m), and renewable dimethyl ether (20% m/m), comparing them to petrol cars and battery electric vehicles. In the EU, this blend could be implemented to reduce the greenhouse gases (GHGs) emissions of the 8.3 million passenger cars currently fuelled with LPG. The blend exploits the transformation of waste products such as used cooking oils, organic wastes, and non-recyclable plastics into fuels, thus helping the transition to a circular economy. Practical use of the blend is possible, as its use resulted in compliance with the standards on marketing (EN 589:2018) and use (Euro 6) of LPG in passenger cars. According to the results of this study, for all the impact categories, the magnitude of impacts increases as the car size increases. Depending on the car segment, the blend reduces GHG emissions by 16-21% compared to petrol, and it shows preference over petrol in 5 impact categories out of 16, while being disadvantageous in 2-5 categories. Electric cars outperform petrol in the same 5 categories (reducing GHG emissions by 36-38% compared to petrol) but are detrimental in ten others. The study revealed increases higher than 200% in water consumption, for all the alternative propulsion systems. Future efforts should focus on fully renewable blends and address the potential limitations of waste feedstock availability used as input for the blend production.