New study estimates impacts of a novel private financing approach on solar adoption for California homes

April 4, 2018

A new study by Berkeley Lab found that residential Property Assessed Clean Energy (R-PACE) programs increased deployment of residential solar photovoltaic (PV) systems in California, raising it by about 7-12% in cities that adopt these programs. R-PACE is a financing mechanism that uses a voluntary property tax assessment, paid off over time, to facilitate energy improvements and, in some jurisdictions, water and resilience measures.

While previous studies demonstrated that early, regional R-PACE programs increased solar PV deployment, this new analysis — Assessing the PACE of California residential solar deployment — is the first to demonstrate these impacts from the large, statewide R-PACE programs dominating the California market today, which engage private capital to fund the upfront costs of the improvements.

Berkeley Lab estimated the impacts using econometric techniques on two samples:

  • Large cities only, allowing annual demographic and economic data as control variables
  • All California cities, without these annual data

Analysis of both samples controls for several factors other than R-PACE that would be expected to drive solar PV deployment.

We infer that on average, cities with R-PACE programs were associated with greater solar PV deployment in our study period (2010-2015). In the large cities sample, solar PV deployment in jurisdictions with R-PACE programs was higher by 1.1 watts per owner-occupied household per month, or 12%. Across all cities, solar PV deployment in jurisdictions with R-PACE programs was higher by 0.6 watts per owner-occupied household per month, or 7%. The large cities results are statistically significant at conventional levels; the all-cities results are not.

The estimates imply that the majority of solar PV deployment financed by R-PACE programs would likely not have occurred in their absence. Results suggest that R-PACE programs have increased PV deployment in California even in relatively recent years, as R-PACE programs have grown in market share and as alternate approaches for financing solar PV have developed.

The U.S. Department of Energy's Office of Energy Efficiency and Renewable Energy-Building Technologies Office supported this research.