PhD student Geet Litjes assessed the technical, economic and environmental benefits of local use of energy generated by rooftop PV systems.
He concludes that about 33% of the PV generated energy of residential systems can be directly consumed by dwellings. This is 44% by commercial buildings. Stationary battery energy storage can charge surplus PV electricity and therefore increase self-consumption. A 1 kWh storage capacity per MWh of annual electricity consumption increases self-consumption by 23% for residential buildings and by 22% for commercial buildings. Only 4% of PV electricity during the systems lifetime is lost when a feed-in limit of 0.5 kW per kWp is imposed. This can be reduced to 0.2% using a 1 kWh storage capacity for each MWh of annual demand. Discounted payback times for PV systems are around 10 years for residential systems and 12 years for commercial systems. Dwellings with a PV capacity of 1 kWp for each MWh of annual demand contribute with about 17 tCO2eq to avoided life cycle greenhouse gas emissions.