US rooftop solar permitting process takes less time, but depends on state - study

The time needed to secure a permit for a rooftop photovoltaic (PV) system in the US is getting shorter overall, but still varies significantly across states, a study released in the journal Energy Policy shows.

The study by Berkeley Lab, which conducts research on behalf of the Department of Energy, analysed data on more than 200,000 PV permits in 39 states to determine how many days pass from the moment an installer applies for a permit up until the solar system passes inspection. According to the findings, the median permit process duration fell to 43 days in 2018 from 68 days in 2012.

The declines were not equal across different jurisdictions. Most of the observed decrease comes from falling permit process durations in Hawaii and other states that represent relatively small rooftop solar markets. Meanwhile, California, which is the biggest state rooftop PV market, has seen the permitting period remaining relatively unchanged.

Berkeley Lab found that 50 days is the typical solar permit duration at the median. But there were significant differences, with half of the total cases studied taking less than 27 days or more than 96 days.

The study concludes that policymakers, permitting authorities and solar installers could identify and implement best practices and share experience-based knowledge to lower permit process durations. In addition, the data suggest that reducing duration uncertainty is as important as lowering durations in general.

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