Techno-economic study of grid connected residential PV system with battery storage - A review of the Local System Operator (LSO) model

Sammanfattning: The grid connected solar PV system with battery storage is one of the promising alternativeenergy solutions for electricity consumers. The Local System Operator (LSO) will be a newactor to operate its own energy system by integrating PV and battery system with other technicalsolutions. This thesis investigates the technical and economic viability of a grid connected PVsystem with battery storage in behind-the-meter approach for aggregated residential load toassess the LSO model for the present conditions in Sweden.The system model is developed using the System Advisory Model (SAM) – a simulationsoftware for renewable energy system analysis. The PV system model is designed using solarirradiation profile and fifty multi-dwelling aggregated residential load data from Sweden. Theappropriate design inputs of solar PV module, inverter and system loss are taken from previousstudies. The electricity price is analysed from the comparative study of Nord-pool wholesaleprice, market retail price and distribution grid tariffs. The financial metrics such as discountrate, inflation rate, system cost and currently available PV incentives are considered to make anaccurate model. To help with the assessment, three cases are formed; the first case representsonly the PV system and the other cases include storage - using a lithium-ion or lead-acid battery.This comparative study helps to determine the optimum PV and battery size at two differentlocations in Sweden.The optimum net present value (NPV) and profitability index (PI) is found at the 40 kW PVand 3 kWh battery system at Karlstad, Sweden. The optimum case is considered for furtherinvestigation to evaluate the system life time energy profile, electricity bill saving capabilityand battery performance. The system peak shaving potential is investigated by making twoother scenarios with higher battery capacity. Sensitivity analysis is also performed to assess thesystem’s technical and financial input parameters. The system capacity factor at the site locationis found as an influential parameter to the annual production and profitability. The optimumsize of PV system with a lithium-ion battery investment is found feasible for the LSO realimplementation only considering the current PV incentives and electricity price in Sweden. Thereport concludes with the assessment, the technical and economic feasibility of the studied PVand battery storage system profitability depends on the system site location, residential loadsize, consumer electricity cost and available PV incentives.