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New 2004 Rules for Connecting your PV System to the Utility Grid
PSC 119 Interconnection Guidelines
Information Resources
PSC 119 Standardizes the Interconnection of Small Renewable Energy Systems in Wisconsin
Introduction
Unlike today's grid-connected systems, the earliest solar-electric systems and wind turbines were designed to operate independently of utilities. Then, in 1982, the Public Service Commission of Wisconsin (PSCW) adopted rules requiring utilities to allow "customer-sited distributed generation (DG) facilities" to be interconnected to their distribution systems.
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Spanning the spectrum from residential solar-electric panels to large installations using diesel fuel, natural gas, or biogas produced at landfills or dairy farms, DG systems produce electricity that is either consumed entirely on site or else fed, in whole or in part, into a utility's distribution system when supply exceeds demand. Initially, the 1982 PSCW rules opened up new opportunities for customer-sited renewable electricity generators that could supply the grid. However, those rules let each utility formulate its own particular set of procedures and requirements for interconnecting customer-owned generators. This resulted in a widely varying patchwork of standards and practices that frustrated both installers and system owners, and dampened customer enthusiasm for owning small-scale renewable generators like PV and wind. By 2001, it was clear to policymakers, installers, and equipment manufacturers that Wisconsin's interconnection rules were obsolete and needed to be reformed. |
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In response to a legislative directive that year, the PSCW opened a docket to revise the 1982 standards. Through this rulemaking docket, the PSCW has overseen the drafting of the new Wisconsin Administrative Code Chapter PSC 119, Rules for Interconnecting Distributed Generation Facilities (also referred to as the DG Interconnection Rules, or PSC 119). The new rules govern the interconnection of non-utility, customer-sited distributed generation facilities to utility distribution systems. One primary objective of the new rules is to make the standards for interconnection of DG systems as uniform throughout the state as practicality allows. Another is to define an step-by-step application process that ensures reasonable review of the proposed installation and timely action by the local utility. The PSC approved the final rules package in December 2003.
The new rules cover a large range of potential DG projects, everything from a 60-watt solar electric panel on a garage roof to a 15-megawatt (MW) gas generator serving a large paper mill. Among renewable technologies, the principal beneficiaries will be solar and wind systems under 20 kilowatts that qualify for net energy billing.
Guidelines for the new interconnection rules were developed during the collaborative process that began in 2001 and served as a foundation for the drafting of PSC 119. The Advisory Committee to the PSCW was composed of electric utility representatives, labor representatives, state officials, distributed generation system manufacturers, dealers and installers, renewable energy advocates, and the general public. The guidelines document will be published in 2004 as a separate document by the Wisconsin Distributed Resources Council, and will include the necessary interconnection forms and agreements. Both the DG Interconnection Rules and the Guidelines will be available at WisconsinDR.org and RENEWwisconsin.org, as well as the PSCW web site (see Information Resources at the end of this document).
Electric Provider Applicability
PSC 119 becomes effective on February 1, 2004. Both the Rules and Guidelines will apply to all public utilities, including all investor-owned and municipal electric utilities. Wisconsin's Rural Electric Cooperatives (REC's) are not subject to PSCW rulings, but are encouraged to use the Wisconsin Distributed Generation Interconnection Guidelines as well.
Pre-Existing DG Systems
In most cases, the adoption of PSC 119 should not force retrofits on pre-existing distributed generation systems. The only exceptions would be if the public utility could demonstrate that the safety and reliability of the utility grid would be threatened without upgrading a particular system. This means that reapplication would only be necessary if interconnection or paralleling equipment (i.e. a new inverter) is replaced.
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