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The U.S. Department of Energy and the North Carolina Clean Energy Technology Center are excited to announce that a new, modernized DSIRE is under construction. The new version of DSIRE will offer significant improvements over the current version, including expanded data accessibility and an array of new tools for site users. The new DSIRE site will be available in December 2014. Staff are currently working hard on the new version of DSIRE but are also maintaining the content of the current version of DSIRE. Thank you for your continued support and patience during this transition. We hope you are as excited for December as we are!

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Incentives/Policies for Renewables & Efficiency

Printable Version
Interconnection Standards   

Last DSIRE Review: 10/06/2014
Program Overview:
State: California
Incentive Type: Interconnection
Eligible Renewable/Other Technologies: Solar Thermal Electric, Photovoltaics, Landfill Gas, Wind, Biomass, Hydroelectric, Geothermal Electric, Fuel Cells, Municipal Solid Waste, CHP/Cogeneration, Fuel Cells using Renewable Fuels, Microturbines, Other Distributed Generation Technologies
Applicable Sectors: Commercial, Industrial, Residential
Applicable Utilities:Investor-owned utilities
System Capacity Limit:No limit specified
Standard Agreement:Yes
Insurance Requirements:Vary by system size and/or type; levels established by CPUC
External Disconnect Switch:Varies by utility and system size
Net Metering Required:No
Web Site:
Authority 1:
Date Enacted:
Date Effective:
CPUC decision 12-09-018

Note: The California Public Utilities Commission (CPUC) approved a proposed settlement in September 2012, enacting the first fundamental redesign of Rule 21 since 2000. The complete revised Rule 21 Tariff, as described at a high level below, can be found beginning on page 136 of CPUC Decision 12-09-018. The individual tariffs adopted by the utilities can be found on the CPUC web site above.

California's "Rule 21" generally applies to systems connecting to an investor-owned utility’s distribution grid, non-export generating facilities connecting to an investor-owned utility’s transmission grid and all net metered facilities in an investor-owned utility’s service territory. Systems connecting to an investor-owned utility’s distribution grid for the purpose of participating in a wholesale transaction must apply under the investor-owned utility’s Wholesale Distribution Access Tariff. Systems connecting to the transmission grid must apply to the California Independent System Operator for interconnection. Systems connecting to the grid of a municipal or cooperative utility must follow the interconnection procedures adopted by that utility.

Rule 21 clearly defines a series of screens meant to filter applicants into the study path most suited for their project. It also establishes fixed timelines for the screens intended to speed the process of approval. Also defined in the tariff are a variety of fees and deposits required at various stages of the interconnection process. Net metered facilities are exempt from most of these fees.

Fast Track Eligibility
Non-exporting systems (sized and designed so that the electricity is only used on-site and will never deliver electricity to the grid) and all net metered systems, regardless of nameplate capacity, can qualify for Fast Track. Exporting facilities may also be considered for Fast Track if they meet certain size restrictions or if the owner agrees to certain utility-approved protective devices.

After a customer applies for interconnection, the utility performs an Initial Review. If the applicant passes through Initial Review, the system will be able to interconnect without a Supplemental Review. If Supplemental Review is required, the applicant will be notified and can elect to have their application withdrawn, or proceed through the next layer of screens.

Detailed Study Eligibility
Systems not eligible for Fast Track may apply for interconnection through a detailed study process. The detailed study options include an Independent Study Process, a Distribution Group Study Process or a Transmission Cluster Study Process. The parameters for each process are provided in Rule 21.

  Rachel Peterson
California Public Utilities Commission
505 Van Ness Ave.
San Francisco, CA 94102
Phone: (415) 703-2872
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Disclaimer: The information presented on the DSIRE web site provides an unofficial overview of financial incentives and other policies. It does not constitute professional tax advice or other professional financial guidance, and it should not be used as the only source of information when making purchasing decisions, investment decisions or tax decisions, or when executing other binding agreements. Please refer to the individual contact provided below each summary to verify that a specific financial incentive or other policy applies to your project.

While the DSIRE staff strives to provide the best information possible, the DSIRE staff, the N.C. Solar Center, N.C. State University and the Interstate Renewable Energy Council, Inc. make no representations or warranties, either express or implied, concerning the accuracy, completeness, reliability or suitability of the information. The DSIRE staff, the N.C. Solar Center, N.C. State University and the Interstate Renewable Energy Council, Inc. disclaim all liability of any kind arising out of your use or misuse of the information contained or referenced on DSIRE Web pages.

Copyright 2014 - 2015 North Carolina State University, under NREL Subcontract No. XEU-0-99515-01. Permission granted only for personal or educational use, or for use by or on behalf of the U.S. government. North Carolina State University prohibits the unauthorized display, reproduction, sale, and/or distribution of all or portions of the content of the Database of State Incentives for Renewables and Efficiency (DSIRE) without prior, written consent.