Electric Rule 21:
Distributed Generation Interconnection Rules
Rule 21 is a set of rules governing how advanced energy technologies may
interconnect with the electric distribution systems of the state’s investor
owned utilities – Edison, PG&E, and SDG&E. These advanced
technologies include Energy
Storage and Distributed Generation
such as roof-top solar.
September 2011, the CPUC opened a Rulemaking to
review and revise Rule 21 to “ensure that the interconnection process is
timely, non-discriminatory, cost-effective, and transparent.”
Reform to Rule 21 have been covered in various proceedings:
CPUC Decision on Rule 21 Reforms
September 2012, the CPUC issued a Decision approving
the first set of reforms to Rule 21 establishing a process to accommodate the
interconnection of exporting generating facilities. Under this reform all
requests made to the utilities to interconnect to their distribution systems
would be designated to one of two major study tracks to be performed by the
Fast Track: A streamlined interconnection review process for
which Net Energy Metering, non-export facilities (not exporting energy to
the distribution system), and some exporting facilities are eligible.
To be eligible for the Fast Track, an applicant must meet a series of
Detailed Study: A more consuming interconnection review process should
the applicant not meet the requirements set forth in the Fast Track.
CPUC Decision on Distribution Group Study Process
April 2014, the CPUC issued a Decision directing
the utilities to incorporate a Distribution Group Study Process into Rule 21.
This Distribution Group Study Process conducted by the utilities, studies
interconnection applicants that are determined to impact one another be
electrically interdependent and will allocate upgrade costs among them.
Interconnection for New Technologies
May 2014, the CPUC issued an Amended
Ruling directing the utilities to
propose specific modifications to Rule 21 to capture new technological advances.
July 2014, the CPUC issued a Ruling setting
the schedule and requesting comments on two CPUC staff reports:
The CPUC opened a Rulemaking to review and revise Rule 21 to “ensure that the interconnection process is timely, non-discriminatory, cost-effective, and transparent.”
CPUC Proceeding Docket
See the Proceeding
Original November 2000 CPUC Decision
establishing Rule 21.