Impact of shared battery energy storage systems on photovoltaic self-consumption and electricity bills in apartment buildings

Distributed photovoltaics is playing a growing role in electricity industries around the world, while Battery Energy Storage Systems are falling in cost and starting to be deployed by energy consumers with photovoltaics. Apartment buildings offer an opportunity to apply central battery storage and shared solar generation to aggregated apartment and common loads through an embedded network or microgrid. We present a study of energy and financial flows in five Australian apartment buildings with photovoltaics and battery storage using real apartment interval-metered load profiles and simulated solar generation profiles, modelled using an open source tool developed for the purpose. Central batteries of 2-3 kWh per apartment can increase solar self-consumption by up to 19% and building self-sufficiency by up to 12%, and shave overall building peak demand by up to 30%. Although the economic case for battery storage applied to apartment building embedded networks is not compelling at current capital prices, with cost thresholds of AU$400 - AU$750/kWh compared to AU$750 - AU$1000/kWh for individual household systems, there are clear financial benefits to deployment of embedded networks with combined solar and battery storage systems for many sites.