Rule 21 Interconnection

Electric Rule 21 is a tariff that describes the interconnection, operating and metering requirements for generation facilities to be connected to a utility’s distribution system.  The tariff provides customers wishing to install generating or storage facilities on their premises with access to the electric grid while protecting the safety and reliability of the distribution and transmission systems at the local and system levels.

Each investor-owned utilities is responsible for administration of Rule 21 in its service territory and maintains it own version of Rule 21:  

Rule 21 Tariff/Interconnection url
 PG&E  Rule 21 Tariff    Interconnection Website  
 SCE   Rule 21 Tariff  Interconnection Website  
 SDG&E   Rule 21 Tariff    Interconnection Website

  

 Table of Contents:

  • Interconnection Rulemaking (R.17-07-007)
  • Interconnection Discussion Forum
  • Dispute Resolution
  • Smart Inverters
  • Interconnection Data Reporting
  • D.16-06-052 Implementation
  • General Information about Rue 21
    • Applicability
    • Overview of Tariff Provisions
    • Regulatory History
     
  • Contact

Interconnection Rulemaking 17-07-007

On July 13, 2017, the Commission issued an Order Instituting Rulemaking to Consider Streamlining Interconnection of Distributed Energy Resources and Improvements to Rule 21. Among the principal topics to be considered in the new rulemaking is the incorporation into Rule 21 of the utilities' Integration Capacity Analysis tools, currently under development in the Distribution Resources Plan proceeding, to inform interconnection siting decisions, streamline the Fast Track process for projects that are proposed below the integration capacity at a particular point on the system, and facilitate interconnection process automation.

For more information on the rulemaking, including information on scope, schedule, working groups, and regulatory history, please visit Energy Division's Interconnection Rulemaking 17-07-007 page.

Interconnection Discussion Forum

CPUC's Energy Division is excited to announce the formation of an Interconnection Discussion Forum that will provide an informal monthly venue for utilities, developers, and other stakeholders to explore a wide variety of issues related to interconnection practices and policies.  The forum, established in Resolution ALJ-347 (approved October 12, 2017), is intended to meet the following objectives:

  • Foster proactive, constructive communication between utilities, developers, and other impacted stakeholders about issues related to implementation of Rule 21 and other interconnection rules;
  • Resolve informally and/or prevent interconnection disputes; and
  • Share information and best practices across utilities and developers

Please refer to the Draft Interconnection Discussion Forum Charter for more information about the scope and structure of the forum.  For questions, please contact Heather Sanders at heather.sanders@cpuc.ca.gov.

First Meeting:  The first meeting of the Interconnection Discussion Forum will be on October 26th from 9:30 a.m - 12:30 p.m. in the Golden Gate Room at the CPUC, 505 Van Ness, San Francisco, CA, with phone lines enabled.  All are welcome.  Agenda and call-in will be sent to the R.17-07-007 service list.

Distribution List:  Energy Division will maintain a distribution list for those interested in attending forum meetings.  To request to be added to the list, please contact Heather Sanders at heather.sanders@cpuc.ca.gov.

Dispute Resolution

Section K of Rule 21 describes existing procedures for resolution of interconnection disputes. For disputes regarding missed timelines, please contact the relevant utility’s Rule 21 ombudsman:

Rule 21 OMBUDSMEN
PG&E
Mike Mulvey
rule21.ombudsman@pge.com
916-472-2250
SCE
Rod Vickers
Rule21.Ombudsman@sce.com
714-895-0211
SDG&E
Joeseph McCawley
JMcCawley@semprautilities.com
858-503-5302

For all other disputes, please use the procedures outlined in Section K of Rule 21. For CPUC assistance in reviewing or resolving a dispute, please contact Heather Sanders, Special Advisor, at Heather.Sanders@cpuc.ca.gov or (916) 327-6786.

Coming Soon:  Expedited Interconnection Dispute Resolution Process

On October 12, 2017, the Commission approved Resolution ALJ-347 establishing an Expedited Interconnection Dispute Resolution Process as authorized by Assembly Bill 2861 (Ting, 2016). The expedited dispute resolution process will issue binding determinations to electric distribution grid interconnection disputes based on the recommendations of a technical panel within 60 days of the Commission receiving the Application regarding a particular dispute. For a detailed description of the adopted process, please see Exhibit A of Resolution ALJ-347.

AB 2826 is intended to address the inadequacy of the existing interconnection dispute resolution process described in utility tariffs in Section K of Rule 21, which relies on protracted mediation and does not benefit from readily-leveraged technical expertise to review the engineering determinations and upgrade cost allocations that often lead to disputes.

While Resolution ALJ-347 allows the Commission until June 12, 2018 to begin accepting applications to the expedited process, Energy Division hopes to begin accepting applications by March 31, 2018. More information on the schedule for launching the expedited process can be found in the table below:

 

Activity Estimate Date
Staff Concept Paper Issued May 30, 2017
Stakeholder Comments Due June 23, 2017
Reply Comments Due June 30, 2017
Staff Proposal Finalized and Draft Resolution Issued September 5, 2017
Comments on Draft Resolution Due September 21 and 26, 2017
Commission Vote on Resolution October 12, 2017
Interconnection Dispute Resolution Panel Assembled* March 31, 2018
Expedited Process Launched (accepting applications) March 31, 2018


For questions about the expedited process, please contact Heather Sanders at Heather.Sanders@cpuc.ca.gov.

Smart Inverters

The Smart Inverter Working Group meets on a regular basis to develop recommendations for advanced inverter functionality requirements. For more information on smart inverter deadlines and working group activities, please see Energy Division’s Smart Inverter Working Group page, or contact Jeffrey Kwan, Utilities Engineer, at Jeffrey.Kwan@cpuc.ca.gov.

Interconnection Data Reporting

Pursuant to Decision (D.) 14-04-003, the three California IOUs submit interconnection data reports to the CPUC Energy Division on a quarterly basis. Public versions of the reports are made available on our Utility Interconnection Data Reports page.

Decision 16-06-052 Implementation

Decision 16-06-052 (R.11-09-011), adopted by the Commission on June 23, 2016, institutes a 25% Cost Envelope for interconnection costs; grants Joint Motions pertaining to Cost Certainty and Non-Exporting, Behind-the-Meter Energy Storage; and requires Rule 21 revisions to incorporate the technical requirements for Phase 2 smart inverter communications and Phase 3 advanced inverter functions as recommended by the Smart Inverter Working Group.

For an update on decision implementation, please visit our D.16-06-052 Implementation webpage.

General Information about Rule 21

Applicability

Rule 21 governs CPUC-jurisdictional interconnections, which include the interconnection of all net energy metering (NEM) facilities, "Non-Export" facilities, and qualifying facilities intending to sell power at avoided cost to the host utility. Rule 21 does not apply to the interconnection of generating or storage facilities intending to participate in wholesale markets overseen by the Federal Energy Regulatory Commission (FERC). These facilities must typically apply for interconnection under the FERC-jurisdictional "Wholesale Distribution Access Tariff" (when connecting to the distribution system) or "CAISO Tariff" (when connecting to the transmission system).

Overview of Tariff Provisions

Rule 21 contains provisions governing many aspects of interconnection, including:

  • Procedures and timeframes for reviewing applications
  • Fee schedules to process applications and perform impact studies
  • Pro forma application and agreement forms
  •  Allocation of interconnection costs
  • Provisions specific to net energy metered facilities
  • Technical operating parameters
  • Certification and testing criteria
  • Technical requirements for inverters
  • Metering and monitoring requirements
  • Procedures for dispute resolution

Regulatory History

The Commission's first iteration of Rule 21 was adopted in 1982.  As initially adopted, Rule 21 was designed to meet the needs of small, non-utility-owned generating facilities, namely qualifying facilities, which included renewable, non-renewable, and cogeneration plants as defined by the Public Utility Regulatory Policies Act.

The Commission revisited Rule 21 in 1999.  Working collaboratively with the California Energy Commission, the Commission undertook a redesign of Rule 21 to establish a more standardized and transparent engineering analysis for the interconnection of distributed generation, especially generation that offsets on-site load.  Rule 21 adopted an "Initial Review" screening process designed to permit the utility engineer to quickly identify, among other factors, whether a generating facility is configured to remain within certain technical limits, and thus unlikely to cause electrical disruptions on the grid. 


The modified Rule 21 successfully facilitated the interconnection of tens of thousands of net energy metered and non-exporting generation facilities between 1999 and 2011.  However, generators seeking to export a portion or all of their generation to the utility's distribution system lacked a straightforward means of interconnecting under Rule 21.  Gaps in the tariff also existed for the interconnection of new technologies, such as energy storage.

On September 22, 2011, the Commission opened Rulemaking (R.) 11-09-011 to "address the key policy and technical issues essential to timely, non-discriminatory, cost-effective and transparent interconnection." During the course of that proceeding, the Commission adopted three substantive decisions: Decision (D.) 12-09-018, D.14-12-035 and D.16-06-052. 

On September 20, 2012, the Commission issued D.12-09-018, which adopted a settlement agreement focused on the interconnection study process.  The settlement agreement required that each utility revise its Rule 21 to assign all interconnection requests to either the "Fast Track" - a screen-based, streamlined review process for net energy metering, non-export, and small exporting facilities - or the "Detailed Study" process for more complicated generating facilities.

On December 18, 2014, the Commission issued D.14-12-035, which adopted revisions to Rule 21 to require "smart" inverters for Pacific Gas and Electric Company (PG&E), Southern California Edison Company (SCE), and San Diego Gas & Electric Company (SDG&E).  D.14-12-035 adopted the revisions recommended by the Smart Inverter Working Group in its January 2014 report "Recommendations for Updating the Technical Requirements for Inverters in Distributed Energy Resources." 

On June 23, 2016, the Commission issued D.16-06-052, which enhanced the Rule 21 Pre-Application Report, created a Unit Cost Guide, enhanced the behind-the-meter electric storage interconnection process, and established a pilot program to institute a cost certainty envelope for interconnections triggering a distribution upgrade.

Despite the significant progress made in R.11-09-011, additional improvements to Rule 21 are needed. On July 13, 2017, the Commission issued an Order Instituting Rulemaking to Consider Streamlining Interconnection of Distributed Energy Resources and Improvements to Rule 21. Among the principal topics to be considered in the new rulemaking (R.17-07-007) is the incorporation into Rule 21 of the utilities' Integration Capacity Analysis (ICA) tools, currently under development in the Distribution Resources Plan (DRP) proceeding (R.14-08-013).  The ICA tools use power flow analysis to determine the ability of a circuit to host distributed energy resources.  Incorporating the ICA tools into Rule 21 may better inform interconnection siting decisions and further streamline the Fast Track process for certain projects.

Contact Us

For utility-specific interconnection inquires, please contact the relevant utility using the contact information found on the utility's interconnection website.

For general inquiries regarding interconnection disputes or Interconnection Discussion Forum, please contact Heather Sanders, Special Advisor, at Heather.Sanders@cpuc.ca.gov or (916) 327-6786.

For inquires regarding smart inverters, please contact Jeffrey Kwan, Utilities Engineer, at Jeffrey.Kwan@cpuc.ca.gov

For all other interconnection-related inquiries, please contact Mary Claire Evans, Regulatory Analyst at MaryClaire.Evans@cpuc.ca.gov

 


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