Techno-Economic Analysis of Residential Grid-Connected Photovoltaic Facilities With Battery Backup, Under the New Spanish Regulation

Abstract

Grid-connected photovoltaic facilities have recently peaked in interest due to the electricity price surges and the reduction of solar energy generation costs. Moreover, surplus electricity can be easily sold to the grid in Spain thanks to the simplified monthly bill scheme defined in RD 244/2019. The overall legislation is complex since it also depends on the electricity market regulation, which changed the 1st June 2021 with a new toll structure. In this study, a Spanish-based simulation model of the lifetime of PV with battery facilities is proposed in order to estimate various techno-economic parameters and find the most suitable facility according to two objectives: maximizing profitability (net present value and internal rate of return) and self-sufficiency. The simulation model examines a total of five load profiles, eleven cities, and four possible electricity price tendencies for the next twenty years. With its results, the techno-economic performance of PV-battery systems can be assessed in order for families and investors to make informed decisions. They also help understand the impact regulation has, specially after the 1st June 2021 change in the tolls structure. Results for the profit maximization indicate that PV panels are already profitable without subsidies, while batteries should reduce its current price. The installed PV capacity largely depends on the load profile, while the solar radiation and compensation rate affect the profitability. The installed capacity per household and city ranges from 2 to 7 kWp. For self-sufficiency maximization, while the profitability drops close to zero, PV capacity doubles, and batteries of up to 5 kWh are added, with a self-sufficiency rate close to 80%. The comparison of these results with those obtained by other researchers indicates that the recent regulatory change has marginally improved the profitability of PV-battery systems. Furthermore, when self-sufficiency maximization is sought, the results indicate that the installed battery capacity has doubled. Finally, the simulation model proposes a PV-battery combination for a real load profile to show-case how investors and families can use it

Objectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminant::7.2 - Per a 2030, augmentar substancialment el percentatge d’energia renovable en el con­junt de fonts d’energia