Distributed energy resources (DERs) include generation and other energy sources that are not centrally-located such as rooftop solar, combined heat and power, demand response and energy storage. In order for the energy of DERs to be grid-available, they must be interconnected with the grid. Processes for interconnection are in evolution as utilities and regulators improve their understanding of interconnection requirements, the potential for streamlining these processes, and maintaining reliability with increased amounts of grid-interconnected DER. This paper explains the process of interconnection of DERs and the technical standards that apply. It describes California Electric Tariff Rule 21 which generally concerns interconnection of distributed power generation with distribution systems and details the technical capabilities of advanced inverters. The paper culminates in options for streamlining interconnection processes and ensuring grid reliability.
This work was accomplished through a Idaho-WIEB State Energy Planning (SEP) project funded by the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, to foster regional and state energy planning in the West and identify opportunities for multi-state or region-wide collaborations to address emerging energy issues.