Comparative analysis of solar - battery storage sizing in netmetering and zero export systems

Solar energy is an intermittent as well as a variable resource. The integration of battery energy storage systems (BESS)with solar photovoltaic (PV)systems can help to mitigate some of the shortcomings of solar energy. In India, many states have a provision for net metering for solar projects. For states that do not allow net metering, a zero-export (grid export curtailed)system emerges as the preferred configuration. This paper presents a techno-commercial comparison of net metering and zero-export systems. An AC coupled grid-connected PV-BESS hybrid system is set up as our reference case so that the PV and battery components can be decoupled. Commercially available components used in actual installations have been selected to enable us to get realistic results. Financial metrics like levelized cost of energy (LCOE)and benefit cost ratio (BCR)are utilized to determine the viability of different system configurations. The optimum size of solar PV, as well as the capacity of BESS which can be integrated with solar PV, is derived, under net metering as well as zero-export regimes. For a 300 kW system, 51 percent of energy is curtailed in a zero-export system, as compared to a net metering system which has no curtailment.