Gasification of agricultural residues to support the decarbonization of the transport sector via electricity generation: a case study

The gradual electrification of transport, particularly private cars, requires widespread electricity availability and potential peak demand in rural or underdeveloped regions could strain the existing electricity network. Therefore, exploring distributed electricity generation is crucial to reduce grid demand and can be an opportunity to promote low-carbon technologies. In this research work we analyze the potential contribution of a biomass gasifier, fueled by vine prunings, in supplying electricity to a local site for electric vehicles charging. The performance of the system is assessed from a technical, economic and environmental point of view. In particular, the specific equivalent CO2 emissions of the system are compared to the alternative emissions of the national power grid, considering the estimated charging profiles based on available patterns from real case studies that incorporate different users’ behaviours and preferences. The electricity produced by the gasifier has a calculated supply chain carbon intensity of 134 gCO2e · kWh−1, which can be sharply reduced to -34 gCO2e · kWh−1, indicating a carbon-negative process, when the carbon sequestration of the co-produced biochar is considered. These figures should be evaluated against a weighted average carbon intensity of the national electricity mix equal to 384 gCO2e · kWh−1 in 2018, while the same figure for 2030 ranges from 141 gCO2e·kWh−1 to 226 gCO2e·kWh−1 depending on the future scenario that is considered. The economic assessment estimates payback times between 6 and 8 years with an average utilization factor of the charging station equal to 14% and a charging price equal to 0.62 e/kWh. In addition to the emission savings that are obtained, this approach could generate further positive effects on the territory: a) the production of electricity allows rural areas to establish their sustainable electric transportation network, reducing their marginalization; b) the production portfolio of farms or agricultural consortia is diversified; c) create a carbon-negative recovery chain for lignocellulosic waste and offers a sustainable solution for their disposal. The results of this analysis can be of use for other researchers dealing with similar topics, and for policymakers that aim to compare available solutions for the decarbonization of the transport sector.