California’s Streamlined DG Interconnection Process Bodes Well for Solar

The California Public Utilities Commission (CPUC) last week approved a deal involving the state’s major utilities and renewable energy advocates that is  aimed at streamlining the process for connecting distributed generation (DG) resources to the grid. The CPUC’s action will make it easier for small amounts of distributed resources—such as rooftop solar photovoltaic (PV) systems—to connect to the grid. The agreement also revises upward the amount of DG that can be connected to a specific power line segment without the need for supplemental studies.

The agreement revises the CPUC’s 13-year-old Rule 21, itself a landmark. Rule 21 set a threshold for instances where the amount of DG on a line section exceeds 15% of that line’s annual peak load. This so-called “15% threshold” was later adopted by the Federal Energy Regulatory Commission (FERC) and also by most states as a model for developing their own interconnection rules. Last week’s action revised California’s standard to allow aggregate interconnected DG capacity equal to 100% of minimum load on a distribution line section.

The settlement agreement was filed with the CPUC on March 16 and involved 14 parties, including Pacific Gas and Electric Co., San Diego Gas & Electric Co., Southern California Edison, Sierra Club, and the Solar Energy Industries Association (SEIA).

SEIA Vice President of Regulatory Affairs Don Adamson told POWERnews his organization filed a motion in February with FERC (Docket No. RM 12-10) urging it to replace the federal 15% threshold with a standard equal to 100% of minimum daylight load. Under FERC rules based on the old California standard, solar projects less than 2 MW in size may enter a “fast track” process of interconnection as long as the total amount of distributed generation is less than 15% percent.

SEIA said that solar developers believed for years that the 15% screen for fast-track interconnection was more restrictive than necessary to maintain distribution system safety and reliability. This view was supported by a January 2012 report “Updating Interconnection Screens for PV System Integration” by the National Renewable Energy Laboratory, Sandia National Laboratory, and the Electric Power Research Institute. The report suggests an alternative fast-track screen—namely 100% of minimum daytime load—can be used when the 15% screen is triggered.

SEIA said that if FERC adopted its proposed revision, the amount of solar wholesale DG capacity eligible for fast-track interconnection would roughly double and make interconnection faster and less costly for many solar projects.

Sources: California PUC, California Energy Commission, Solar Energy Industries Association

—David Waman is POWER’s executive editor (@EPContentDirect)