Determinants of electricity bill savings for residential solar panel adopters in the US: A multilevel modeling approach

This study provides a comprehensive examination of factors that affect the electricity bill savings of a sample of solar adopters in four U.S. states. A multilevel model is used to capture the role of variations across state policies and local regulations, and examine their effect on savings after controlling for household characteristics. We find that solar adopters located in zip codes with higher photovoltaics penetration have significantly higher summer savings. This suggests that local policies that remove barriers for the wide adoption of solar panels across multiple households would be in alignment with increasing the private value of solar panels. Furthermore, we find that solar adopters in zip codes with smaller installed capacity have higher summer savings. The analysis in this study suggests that, to achieve higher savings, local policies that regulate size are less effective compared to policies that remove barriers to a wider photovoltaics adoption. Finally, this study finds evidence for the role of certain household-level variables in explaining the electricity bill savings of solar adopters. Solar-savings-calculators can be customized to include some of these house and resident characteristics.