Road transport in Europe contributes 740 million tons of CO2 emissions annually, with heavy goods trucks and buses accounting for 28 % of these emissions. To reduce greenhouse gas emissions in the transport sector, the European Union has issued the Renewable Energy Directive (RED), which has been revised as RED II since 2021 and expanded in 2023 as RED III. These directives specify the requirements that biofuels, liquid and gaseous renewable fuels, and Recycled Carbon Fuels (RCFs) must meet to be considered sustainable and creditable, particularly regarding their greenhouse gas emissions. The paper focuses on industrial research into operating line buses with on-farm produced bio-LNG with the overall goal of reducing CO2 emissions to less than 0 kg per kilometer. The entire process chain is presented, from on-farm production of bio-LNG, fuel logistics, the implementation of a serial hybrid drive in an 18-ton bus to the necessary filling station and workshop technology. To optimize bio-LNG production, RED II-compliant substrate mixtures based on manure, horse manure, and organic residues are used. The bio-LNG production is based on the two-stage pressure fermentation patented by the University of Hohenheim. The advantages of the process are the almost complete utilization of biomass for bio-LNG production and significant investment and operating cost advantages compared to other processes. Additionally, the process allows direct utilization at filling stations. The drive concept features an electric bus equipped with a range extender, notable for its energy efficiency due to its recuperation capabilities. The range extender enhances the vehicle's range, fulfilling rural public transport requirements of at least 500 km. The greenhouse gas emissions associated with the production of bio-LNG range from -36.9 to -120 g CO2 per megajoule (MJ), indicating a net negative emission profile.
Session:
Energy, Infrastructure and LCA
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| 11:30-12:00