Bidirectional EV Charging Allows Deep Decarbonisation of the UK Residential Sector

Charging an electric vehicle (EV) from a residential solar photovoltaic (PV) system, aided by the EV being parked at home for some or all of the time, substantially reduces a household's monthly electricity bill, its cost for an energy storage system, and its CO ₂ emissions. These benefits improve dramatically with bidirectional charging, where the EV is allowed to discharge electrical energy. We find that, at the household-level, each individual element significantly reduces both costs and emissions and their simultaneous adoption has substantial additional benefits. For example, a household with a PV system and an electric vehicle used only for occasional commutes emits up to 66% less CO ₂ than a household that has neither. At the national level, 90% adoption of bidirectional residential EV charging could reduce the UK's CO ₂ emissions by nearly 55%. Therefore, we urge policymakers and regulators to encourage the rapid adoption of bidirectional EV charging from residential solar PV.