Note: The data set only includes interconnected solar PV Net Energy Metering (NEM) projects and presents the current "state of the world" in terms of how many interconnected solar PV projects and how many megawatts are installed in a given geographic area. Calculations based on "Application Approved Date." Includes standalone solar PV projects and hybrid projects (e.g. solar PV plus battery storage). Other includes the education, military, non-profit, and government sectors.
Data Source: Currently Interconnected Data Set, California Solar Statistics.
Analysis by CEC Economics
Highlights
- After a stellar year in 2023, 2024 was a relatively muted year of interconnected distributed capacity of solar within the three investor-owned utilities service territories, totaling just 1,600 MW (in alternating current). This represents a drop of 29.9% compared to 2023. Residential continues to be the largest end-use sector, accounting for over half (62.1%) of the interconnected distributed generation installed (993 MW) in 2024. However, this is a 46.8% decline relative to the 1,865 MW in 2023. Notably, the residential sector is the only major sector where interconnected solar is growing.
- Although interconnected solar fell in the residential and industrial end-use sectors in 2024 relative to 2023, it rose 68.0% or 197 MW in the commercial sector. Outside of these three major sectors, interconnected solar also rose in the educational sector (+33.5% or 15.8 MW), military (+1,351% or 1.8 MW), and non-profit (+76.1% or 5.5 MW). Interconnected solar for the first half of 2025 is on pace compared to 2024 with an addition of 797 MW year-to-date.
Opportunity
- In 2023, California became the first state to require both solar PV and energy storage systems on all new and some retrofitted commercial buildings, following the California Energy Commission (CEC) update to the 2022 Building Energy Efficiency Standards.85 This could lead to a rebound in storage installations from the residential and commercial sectors. Indeed, in the residential sector, after the new net billing tariff (NBT) replaced the net energy metering (NEM) tariff in April 2023, storage attachment rates, or the rate of PV systems installed paired with a storage system, rose from about 10% under the NEM tariffs to 60%.86
85 California Energy Commission.2022 Building Energy Efficiency Standards Title 24, Part 6, and Associated Administrative Regulations in Part 1. December 23, 2022. Assessed August 15, 2023. Available at: https://www.energy.ca.gov/publications/2022/2022-building-energy-efficiency-standards-residential-and-nonresidential.
86 Barbose, Galen. “One Year In: Tracking the Impacts of NEM 3.0 on California’s Residential Solar Market.” Lawrence Berkeley National Laboratory, May 2024. Available at: https://live-lbl-eta-publications.pantheonsite.io/sites/default/files/ca_
nem_3.0_technical_brief.pdf
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