A Comprehensive Robust Techno-Economic Analysis and Sizing Tool for the Small-Scale PV and BESS

Battery energy storage systems (BESS) are receiving great attention due to their ability in maximizing self-consumption and energy arbitrage. However, in many countries, BESS profitability is still questionable without subsidy due to their high capital costs. This paper proposes an open-source generic tool to provide comprehensive techno-economic analysis on the small-scale PV/BESS. The proposed tool utilizes real-time BESS control method that has been validated using real experimental measurements in addition to integrating a reliable degradation model to determine the loss in savings due to capacity degradation. The profitability is investigated by conducting different cost-benefit analyses for the PV and BESS. An optimization layer is introduced to find the optimal PV/BESS sizes that boost investment profitability by maximizing the net present value. A detailed case study is presented for a household in the U.K. under three different tariff structures that consider practical parameters and assumptions. Furthermore, sensitivity analyses are performed to evaluate the impact of the cost-benefit analysis assumptions on the PV/BESS sizing and profitability. Finally, the BESS investment viability is investigated over the next few years for different investment expectations to answer the question of when the BESS should be installed to be a viable economic-attractive option in the U.K.