Distributed Generation Interconnection Standards

A survey by the National Renewable Energy Laboratory found that virtually all distributed generation projects meet some sort of resistance from utilities when they try to interconnect with the grid. These onerous and/or expensive interconnection requirements, including some that may be unnecessary, comprise a key barrier to increased use of distributed power.

Prior to 2005, there were a variety of efforts underway at the federal level and within individual states to develop fair and uniform interconnection standards to help facilitate the deployment of distributed generation.

Withthe passage of the federal Energy Policy Act of 2005 (EPAct 2005), section 1254 of EPAct requires states and "nonregulated" utilities to commence consideration of an interconnection standard based on the IEEE 1547 standard on or before August 8, 2006, and to make a determination regarding this standard on or before August 8, 2007. The folks at IREC are tracking these state level efforts at this link.

Find Below Interconnection Rules for DG Projects:

Federal Initiatives

The Institute of Electrical and Electronics Engineers (IEEE) Standards Coordinating Committee 21 continues development of the IEEE P1547 Draft Standard for Distributed Resources Interconnected with Electric Power Systems.

Additional Information:
IEEE Standards website
P1547 Working Group Web site


  • IEEE Distributed Resources Interconnection Standard
    In March 1999, the Institute of Electrical and Electronics Engineers (IEEE) Standards Association Board voted to undertake the development of uniform standards for interconnecting distributed resources with electric power systems. The IEEE Standards Coordinating Committee 21 (IEEE SCC21), the committee responsible for developing technical standards for distributed technologies, is now working to develop IEEE P1547, the Standard for Distributed Resources Interconnected with Electric Power Systems. There are also now a handful of subparts to P1547 that are in various stages of development. This standards package, when approved and adopted, is expected to be a key milestone in the quest for a standardized and appropriate interconnection standard for the U.S. power industry. The objective is to establish minimum technical criteria and requirements for interconnection of distributed resources with the electricity delivery grid to achieve the ultimate goal of development of a uniform standard for electrical interconnections. The standard will address conditions necessary for optimum performance, operation, testing, safety and maintenance of interconnected distributed resources.
  • IEEE Small-Scale PV Interconnection Standard
    In January 2000, the IEEE Standards Board approved a standard for interconnecting photovoltaic (PV) systems under 10 kW to the utility grid. The new standard, entitled Recommended Practice for Utility Interface of Photovoltaic Systems, is referred to as IEEE Standard 929-2000.

Federal Energy Regulatory Commission (FERC)

State Initiatives



Aregulatory proceeding in California addressing the distributed power interconnection issue was started at the California Public Utilities Commission (CPUC) as a result of the 1999 order (R.99-10-025). The CPUC proceeding was completed and they issued an order on December 21, 2000 establishing distributed power interconnection standards for three of the state’s utilities – Pacific Gas and Electric Company, San Diego Gas& Electric Company, and Southern California Edison Company. Other utilities in the state were directed to adopt the standards or submit a filing demonstrating compelling reasons why the adopted rule should not be adopted.



  • Minnesota Distributed Generation Interconnection Standards and Tariffs
    Two work groups were established by the MN PUC to develop the guidelines for utilities to use in developing a standard tariff and technical interconnection standards for distributed generation projects under 10 MW. A wealth of background materials are posted in this section. Final interconnection standard was adopted in September 2004 and DG tariff proposals have been filed in December 2004.

New York

InDecember 1999, the New York Public Service Commission (NYPSC) issued a final order addressing interconnection of distributed generation (DG)resources of 300 kilowatts (kW) or less. The order addresses general technical guidelines for interconnection and application procedures. As part of an ongoing review of the requirements, substantive revisions were proposed and adopted in 2002 and 2003. Further review process in 2003 yielded changes consisting primarily of an increase in the upper capacity threshold from 300 kW to 2 MW, the adoption of an Underwriter’s Laboratories (UL) standard for equipment certification, and the extension of the applicability beyond only radial distribution systems to also now include network distribution systems. The NY PSC adopted new rules in November 2004.


TheTexas Public Utility Commission (PUC) adopted final rules (Project No. 21220) in December 1999 addressing technical and contractual issues related to installing distributed resources. The Texas standards place the burden of proof on the utility to show if an interconnection should be disallowed. The Commission adopted a standard interconnection agreement and a standard tariff interconnection form. In February of 2001, the PUC released the final version of their Distributed Generation Interconnection Manual (Project No. 21965).


Wis. Stat. § 196.025(4)) required the WI Public Service Commission to study the establishment of a program for providing incentives for the development of high-efficiency, small-scale electric generating facilities. New rules for inteconnection of DG projects of 15 MW and less were adopted in February 2004.

More Information: