Data Analytics for Residential PV from Permit to Interconnect: Final Technical Report

This project is the first analysis of PII leveraging a nationwide dataset of installer data. This analysis identified the individual and cumulative effects of PII on process cycle times. Though there was some initial literature focused on interconnection (Ardani et al. 2015), this effort was the first to couch these interconnection requirements within the linked permitting and inspection process. In addition, this project is the first to evaluate how cancellations are associated with PII related delays and the types of costs that may need to be passed on to successful installs. Moreover, this work is the first to provide insights regarding how installer size can influence PII timelines, related cancellation rates, and potential cancellation costs. NREL collected PII-related data on 364,176 projects, across 34 states, 7238 jurisdictions, and 560 utilities from 2017 - 2021. NREL found that permitting cycle times range from 0-35 business days; and interconnection review timelines for pre-installation review ranged from 0-24 business days; while post-installation reviews ranged from 0-72 business days. NREL published this data in an interactive web tool, that also provided detailed PII-related requirements that contractor must follow within each local government and utility, thereby increasing transparency into potential adoption timelines and PII-related requirements nationwide. Over the course of the project, NREL modified the project plan to expand scope and collect more PII-related data. The key barriers that NREL faced in completing this project related to identifying willing data partners to improve the coverage of the dataset and conducting data analysis with only contractor-provided data as opposed to comparing that data with other sources such as utility and local government data.