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Interconnection Standards

Interconnection Documents and Resources

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Standard interconnection rules establish clear and uniform processes and technical requirements that apply to utilities within a state. These rules reduce uncertainty and prevent time delays that clean distributed generation (DG) systems can encounter when obtaining approval for electric grid connection.

States that modified interconnection rules focusing only on net-metered systems have found these changes were insufficient to encourage clean DG. This is largely due to the small capacity limits on net-metered systems, which limits larger DG systems from accessing the grid for backup power.

Presentations from the June 26, 2008 webinar on "Interconnection Standards: Best Practices for Effective Rules and Standards" presentations are also available.

Interconnection Benefits

Standardized interconnection requirements support the development of clean DG by providing clear and reasonable rules for connecting clean energy systems to the electric utility grid. This helps states achieve success with other clean energy initiatives.

2008 Research

EPA evaluated the favorability of interconnection standards for distributed generation in February 2008 as part of a review of clean energy programs. The evaluation showed 31 states had adopted standard interconnection rules for DG, and 11 additional states were in the process of developing rules. The maps below show which states had interconnection rules in place at that time, and which of the existing interconnection rules are friendly to DG.

State Interconnection Standards

Image of US map with highlighted states showing states showing State Interconnection Standards

Policy in place:
AR, AZ, CA, CO, CT, DE, FL, GA, HI, IN, MA, MI, MO, MN, NH, NJ, NM, NY, NV, NC, OH, OR, PA, SC, TX, UT, VT, VA, WA, WI, WY

Action is pending/possible:
AK, DC, IA, ID, IL, KS, MD, SD, TN, WV

Some elements of policy are in place:
KY

Policy not in place:
AL, LA, ME, MS, MT, NE, ND, OK, RI

Established State Interconnection Standards: Assessment for DG Friendliness

US map with highlighted states showing states with Established State Interconnection Standards: Assessment for DG Friendliness

Favorable Interconnection Standards:
CA, CT, DE, IN, MA, MI, NH, NJ, NY, NV, OH, OR, PA, VT, WA

Unfavorable Interconnection Standards:
AR, FL, GA, KY, LA

Neutral Interconnection Standards:
AZ, CO, HI, MN, MO, NC, SC, TX, UT, VA, WI, WY

No policy in place:
AL, AK, DC, ID, IA, IL, KS, ME, MD, MS, MT, NE, NM, ND, OK, RI, SD, TN, WV

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Research Approach

EPA's research project set out to assess interconnection rules based on the following items:

  • Standard interconnection forms
  • Simplified procedure for smaller systems (typically 10 kW or less)
  • Timeline for application approval
  • System size limits
  • Insurance requirements
  • Technical requirements

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Assessment

EPA assessed the DG friendliness of existing interconnection rules through the following criteria:

  • Favorable: Indicates that there is a well-defined interconnection policy in place that has at least one or more beneficial attributes:
    • Standard forms
    • A reasonable timeline for application approval
    • Low or no additional insurance requirements
    • Allows for >10 kW residential and >100 kW commercial D units to interconnect
    • May have additional positive attributes
  • Neutral: Indicates that there is an interconnection policy, but overall the policy cannot be considered either beneficial or detrimental to DG.
  • Unfavorable: Indicates that the interconnection policy may be available, but has unfavorable requirements such as:
    • Only allowing small units to interconnect (<10 kW residential and <100 kW commercial)
    • Having high liability insurance requirements
    • Requiring owners/operators to pay large interconnect study fees
    • May have other burdensome requirements

EPA assessed 50 states and the District of Columbia and found the following results:

  • 55% have standard interconnection forms
  • 29% have a simplified procedure for smaller systems
  • 35% have a set timeline for application approval
  • 45% have larger system size limits (over 10 kW for residential and over 100 kW for commercial systems)

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State Examples

  • The Oregon Public Utility Commission adopted interconnection standards in July 2007 after a nearly year-long stakeholder process. This rule allows non-residential IOU customers with systems up to 2 MW to interconnect. They started with the Mid-Atlantic Distributed Resources Initiative (MADRI) model rule and made several improvements:
    • Added “field certification” concept
    • Non-inverter-based Level 2 fast tracking up to 2 MW
    • Increases Level 1 to 25 kW
  • In June 2002, the Massachusetts Department of Telecommunications and Energy (DTE) initiated a rulemaking to develop interconnection standards for DG. The policymakers within the DTE established a DG Collaborative to engage stakeholders (including utilities, DG developers, customers, and public interest organizations) to jointly develop a Model Interconnection Tariff, which established a clear, transparent, and standard process for DG interconnection applications.
  • New York was one of the first states to issue standard interconnection requirements for DG systems. Enacted in December 1999, the initial requirements were limited to DG systems rated up to 300 kilowatts (kW) connected to radial distribution systems. In September 2005, New York modified these interconnection requirements to include interconnection to radial and secondary network distribution systems for DG with capacities up to 2 megawatts (MW).
  • In November 1999, the Texas Public Utility Commission adopted substantive rules that apply to interconnecting generation facilities of 10 MW or less to distribution-level voltages at the point of common coupling. This ruling applies to both radial and secondary network systems. The rules require that Texas utilities evaluate applications based on pre-specified screening criteria, including equipment size and the relative size of the DG system to feeder load. These rules are intended to streamline the interconnection process for applicants. Texas's interconnection standards can be found in the Distributed Generation Interconnection Manual (PDF) (114 pp, 2MB).

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Additional Resources

If you would like additional assistance, please contact Neeharika Naik-Dhungel (naik-dhungel.neeharika@epa.gov).

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