Environmental and economic impact of household energy systems with storage in the UK

Households accounted for 35% of total UK electricity consumption in 2019 and have considerable potential to support the target of net-zero CO2 emissions by 2050. However, there is little understanding of the potential to reduce emissions from household energy systems using emissions-responsive battery charging, and existing investigations use average emissions factors rather than marginal. To understand the overall carbon reduction potential of household energy systems, a life cycle assessment has been conducted for a typical house in the UK, with annual electricity consumption of 3960 kWh. Household energy systems comprising solar photovoltaics arrays and battery energy storage systems are assessed using time-series consumption and generation data, determined by combining a validated demand model, marginal emissions factor calculations, storage system models, and assumptions regarding the future grid. Marginal emissions factors are used to calculate the life cycle carbon emissions of electricity consumption. The carbon emissions and financial costs of household electricity consumption have been estimated for different combinations of battery storage, photovoltaics arrays, and smart battery charging systems. Results show that the deployment of a rooftop photovoltaics array and lithium nickel-manganese-cobalt battery operating in response to grid emissions factors could achieve 14 tons of CO2 savings through the system’s life span, though total electricity costs would be increased considerably. The household with just a photovoltaics array and no battery storage could increase total electricity costs by £2170 and achieve 12 tons of CO2 savings through the system’s life span, providing much improved marginal abatement costs over systems with battery storage. The battery operation mode and the characteristics of batteries and photovoltaics systems in carbon emissions reduction are discussed. High cost is the main factor limiting the deployment of household battery systems.