A Data-Driven Analysis of Rooftop Solar PV Permitting Timelines in the United States
Friday, October 9, 2020
2:05 PM – 2:15 PM EDT
Objective: PV permitting processes have been identified as a key barrier to large-scale rooftop PV deployment in the United States. Our objective is to explore PV permitting timelines and the factors that explain differences in permit durations in the United States.
Methods: We leverage a novel data set with install-level time stamps for different stages in the PV permitting process: permit application; permit issuance; and passed inspection. We compare PV permit durations across jurisdictions and installers. We explore the factors that explain differences in permit durations through a duration analysis model.
Results: PV permit durations vary significantly across installs, jurisdictions, and installers. About half of systems pass an inspection within 42 days from the permit submission, while 25% of systems take longer than 85 days to pass inspection from permit application. Differences in jurisdiction-level permitting requirements may explain some variation in permit durations. For instance, durations are generally shorter in California, where a host of state-level policies have been implemented to expedite the permitting process. However, jurisdiction-level policies may have limited impacts on permit durations due to the key role of installers. The data show that some installers are consistently associated with longer permit durations than others, indicating that different installer strategies may result in variation in permitting timelines. Finally, the data show that permit durations have declined over time in some markets (e.g., Hawaii) while remaining relatively stable in other key markets (e.g., California). A duration analysis model provides evidence that jurisdictions learn to reduce permit durations as they accumulate more experience with PV permitting.
Conclusion: PV customers in the United States face uncertain and potentially lengthy PV permitting processes. The uncertainty of the PV permitting process may deter risk-averse customers from pursuing rooftop PV adoption. The data provide evidence that most PV permit durations could be shorter if more jurisdictions adopted permitting best practices applied in jurisdictions with relatively short permit durations. The data also show that installers play an important role in determining PV permit durations. The results provide a rationale for policies that engage permitting agencies and installers to yield shorter durations and more consistency in PV permit processes.