Environmental consequences of vehicle-to-grid for a future energy system: A case study of Eastern Denmark

With the European Union’s ambition to become carbon-neutral by 2050, the transport sector is expected to decrease its greenhouse gas emissions by 90%. Vehicle fleet electrification is one way of reaching the ambitious targets and it can at the same time, combined with an increase of renewable energy sources (RES), help to enhance decarbonizing the energy system. While extensive literature is dedicated on investigating the techno-economic feasibility of electric vehciles (EVs) providing vehicle-to-grid (V2G) service, limited knowledge is available about the environmental impacts and modelling of V2G integration into energy systems and resulting consequences.
When conducting a Life Cycle Assessment (LCA) of energy systems, EVs are represented as part of the electricity consumption, but not modelled as assets. By providing V2G, the EVs are no longer only electricity consumer, but function as electricity storage and thereby help to increase the RES penetration rate of the energy system. Hence, the EVs providing V2G service should be included in the LCA of the energy system. However, this raises various LCA methodological questions when modelling energy system including V2G service of EVs. Above all, it remains unclear whether the benefits of increased RES penetration in the energy system surpass the environmental burden related to the EVs battery manufacturing.
Therefore, this study conducts a consequential LCA for providing V2G service at the Danish island Bornholm in 2050. In a first step, the current energy system is assessed, using the EnergyPLAN software, data from national statistics, the ecoinvent database and further primary data about the V2G provided electricity of the Bornholm island. In a second step, the year 2050 is modelled by assuming an 100% EV penetration of the vehicle fleet at the Danish island. The assessment provides the impacts on climate change per kilowatt hour and explores the consequences on the marginal electricity mix of the island.
Results are expected to show a difference between the climate change per kWh of the existing energy system and the energy system in 2050 including a 100% EV fleet, that will provide V2G service. Furthermore, the impacts of providing V2G service on the marginal electricity production will be presented.
Thereby, potential conclusions on the advantageousness of V2G service for an energy system can be revealed. Furthermore, the case study is expected to advance the LCA methodology of EVs providing V2G service and resulting consequences on the energy system.