Economic Analysis of Solar PV and Batteries for Common Residential Electricity Rate Structures Using Green Button Data

Rising electricity prices, falling photovoltaic (PV) system costs and the availability of net metering are encouraging consumers to consider PV systems. However, the variety and complexity of utility rate structures can be a formidable barrier to consumers in making economically informed decisions. This paper describes a methodology to integrate Green Button energy use data from electric utilities, with solar and temperature data to analyze the economics of PV systems, with and without battery storage, under different rate structures. Case study results indicate that the economics of PV systems are nearly identical under PG&E’s time-of-use and inverted-block rate structures, and are more favorable than under flat rate structures with the same average annual cost per kWh. However, simple paybacks remain well short of the typical life of PV systems. The simple payback for the addition of batteries is initially competitive with PV systems, but rises rapidly as battery size is increased.