Impact of OMEx e-fuels for CO2 emissions abatement in light-duty commercial vehicles

E-fuels, such as oxymethylene dimethyl ethers (OMEx), represent a promising alternative to conventional fuels to reduce engine emissions and extend their durability. They are highly oxygenated fuels that allow emissions reduction because of smoke-free combustion. Recent studies have highlighted that adopting scaled injection systems can overcome their lower energy content. The aim of this work is to provide a preliminary well-to-wheel analysis by merging the most recent literature findings concerning well-to-tank with a detailed tank-to-wheel assessment. The analysis considers different OMEx types and diesel/OMEx blends to compute energy demand, fuel consumption, and carbon dioxide emissions of a delivery van subject to a given driving cycle. From literature evidence, the average improvement in engine efficiency attained by using pure OMEx fuels has been estimated to be approximately 4.5% compared to pure diesel, with greater values for short-chain OMEx (e.g., up to 10%). From the obtained results, a reduction in tank energy requirement was observed, with a minimum of −10% for pure OME2. However, fuel consumption increases because of OMEx lower energy content, showing a growth ranging from 74% to 140% in mass and from 65% to 86% in volume with increasing chain length of pure OMEx. The variation in CO2 emissions is not univocal, since a reduction of almost −4% for pure OME1 and an increase above 20% for pure OME4 were achieved. The obtained results highlight how OMEx with shorter chains can lead to greater efficiencies compared to pure diesel, with a slight reduction in CO2 emissions.