U.S. Department of Energy - Energy Efficiency and Renewable Energy
Tribal Energy Program
Grid Interconnection Issues
When new large power facilities are connected to the grid, the grid facilities must be adjusted to handle it. Grid connection usually takes place at a substation — either an existing substation with room for growth, or at a new substation built for the project. The owner of each substation allows new customers on the system on a first-come-first-served basis. To determine if there is available capacity between that substation and the new generator's customers, studies must be made and shared with the regional body of the North American Electric Reliability Council (NERC) to determine the impact of the new addition to the system. These studies can be quite expensive, depending on the location on the grid and the size of the project. However, completing these studies and applications allows proposed new facilities to earn a place in a queue that manages competing applications.
All newcomers to the grid must meet numerous standards. The studies described above provide for the safety of the interconnection and document effect the interconnection will have on the grid, and hopefully prove that power can travel to the customers of the generator. In addition to these studies, interconnection standards must be considered. Standards are policy level, such as non-discriminatory access; physical, such as the types of equipment that are necessary; and process, such as the safety steps for actually hooking up new facilities.
If one is interconnecting with a federal or state regulated public utility, the state and/or federal rules should be researched. If the interconnection is at the wholesale level (at higher voltages for larger facilities) federal standards will apply. Regulated utilities will have federally approved tariffs governing larger interconnections. The Federal Energy Regulatory Commission (FERC) is in the process of establishing new federal rules that govern interconnections and attempt to standardize the procedures and standards for all new wholesale interconnections. The new rules are drafted to remove impediments to the interconnection of renewable energy systems and to encourage fair and non-discriminatory access to the grid. Once the new federal rules are in final form, they will require that all jurisdictional utilities conform to the new federal rules. If any party feels they are unfairly restricted from access to a grid interconnection under the federal rules, a filing of a protest or other appropriate filing may be made before FERC.
If the interconnection is with a state regulated public utility, and at a retail level, sometimes state standards may exist, and sometimes they may not. The state-approved tariffs on file by the utility, and generally available on-line, may describe the procedures for interconnection. In any case, direct conversation with the utility company with whom you wish to interconnect is imperative to successful and safe interconnections.
Note that some utilities allow net metering for small generators, letting these generators earn credit for any power fed into the grid, often by literally allowing their meters to spin backwards. See the Exporting Electricity section of this Guide.
When interconnecting with a non-regulated utility, a tribe should contact the utility to determine their rules. Copies of all published rules should be obtained, along with the charter and bylaws of the utility, so an understanding of how rules are made can be researched.
All interconnections are subject to interconnection agreements. The agreement forms are often standardized and describe the procedures, practices, tariffs, and other terms of an interconnection. When forming these agreements, the advice of legal experts is usually needed to assure that all parties have fully negotiated all the important matters.
For More Information
See the Guide section on Interconnection of a Tribal Utility for more information on connecting your own utility to the electricity grid
The Interstate Renewable Energy Council (IREC) has prepared a detailed report, Connecting to the Grid: A Guide to Distributed Generation Interconnection Issues, that contains useful information for interconnecting small power systems to the grid. See the report (PDF 1.4 MB). Download Adobe Reader.
DOE's Energy Savers Web site includes detailed information on connecting small power sources to the grid. See Connecting Your System to the Electricity Grid on the Energy Savers Web site.
IREC's Database of State Incentive for Renewable Energy (DSIRE) includes information about interconnection standards in each state, as well as net metering rules and a variety of regulations and incentives that may apply to your system.