The Missing Correlation Between the Potential Rate Impacts of Rooftop Solar and the Timing of State Net Metering Policy Revisions

Description

Data supporting the article “The Missing Correlation Between the Potential Rate Impacts of Rooftop Solar and the Timing of State Net Metering Policy Revisions” (https://www.nrel.gov/docs/fy25osti/93543.pdf).  Residential solar photovoltaic (PV) output in most states is credited at the retail electricity rate, a policy commonly known as net metering. Twelve states have replaced net metering with alternative rate structures that reduce PV adopter bill savings. Proponents of these revisions argue that net metering increases the electricity rates of customers without PV. Here, we analyze the degree to which the timelines of net metering revisions have correlated with potential electricity rate impacts. We estimate that potential rate impacts at the end of 2023 were less than 1% of typical customer bills in 37 of 44 states that have offered net metering. There are no statistically significant differences in average or median estimated rate impacts between states that have and have not revised net metering. Nine of the states that had revised net metering did so when estimated impacts were less than 1% of typical customer bills. Many states have retained net metering into higher PV deployment levels with increased risk of potential rate impacts. Only two states-California and Hawaii-retained net metering beyond estimated rate impacts of 5%, and both have revised net metering. These findings do not suggest a clear, consistent link between net metering revision timelines and potential rate impacts. The timing and nature of net metering revisions are ultimately policy decisions based on state-level priorities and considerations. 

Resources

Name Format Description Link
5 Script to generate California-specific inputs for analysis https://data.nrel.gov/system/files/299/1755287213-ca_calcs.R
0 Archive contains raw data inputs for the VoS/CoS ratios, including data from the U.S. Energy Information Administration (eia), the Bureau of Labor Statistics (cpi.csv), and U.S. Census population data (state_hh). The file nem_tracking was compiled by the authors. https://data.nrel.gov/system/files/299/1755287213-Data.zip
5 Script to generate basic descriptive stats and Figures 2 and 3 https://data.nrel.gov/system/files/299/1755287213-descriptives.R
5 Archive for output figures https://data.nrel.gov/system/files/299/1755287213-Figures.zip
5 Script with primary analyses and figures https://data.nrel.gov/system/files/299/1755287213-vos_cos_analysis.R
5 Content description https://data.nrel.gov/system/files/299/1755287213-readme.rtf
5 Archive for script data outputs https://data.nrel.gov/system/files/299/1755287213-Outputs.zip
0 Generates the VoS/CoS ratio outputs that form the primary basis for the analysis. The remaining scripts can be run in any order. https://data.nrel.gov/system/files/299/1755287213-0_gen_vos_cos_ratios.R
5 Script with inputs underlying other scripts, do not modify https://data.nrel.gov/system/files/299/1755287213-prep.R

Tags

  • solar
  • rates
  • net-metering

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