Small Generators May Soon Be Required to “Ride Through” System Disturbances
The Federal Energy Regulatory Commission (FERC) has issued a Notice of Proposed Rulemaking (NOPR) to revise its pro forma Small Generator Interconnection Agreement (SGIA). The new rule would require small generators (those that are 20 MW or less) to “ride through” through or to stay connected to and synchronized with the transmission system during a system disturbance.
Specifically, section 1.5.7 of the SGIA would require interconnection customers to ensure the frequency and ride through capability and the voltage ride through capability of small generating facilities. It would also require that such facilities not disconnect automatically or instantaneously from the system or equipment of the transmission provider and any affected system for an under-frequency or over-frequency condition, or an under-voltage or over voltage condition.
Finally, the transmission provider would be required to coordinate the small generating facility’s protective equipment settings with any automatic load shedding program. FERC currently imposes these requirements on large generators (those over 20 MW) but had previously held off on applying them to small generators in order to allow other outside entities and organizations time to evaluate similar standards.
In considering the adoption of a new standard, FERC recognizes that small generators have become more prolific and, as such, their impact on the grid has changed. FERC also points to the high concentration of distributed energy resources, their impact on the reliability of the grid, and the need to mitigate potential adverse impacts. While FERC acknowledges that certain geographic areas have a higher concentration of small generating facilities, if adopted, the new rule would apply on an industry-wide basis. Additionally, rather than adopt specific frequency and voltage ride through parameters in the NOPR, FERC plans to work with various entities to develop appropriate system-specific standards.
FERC also clarifies that the proposed rule is not intended to interfere with any state-level interconnection procedures and would apply only to interconnections made subject to a FERC-jurisdictional open access transmission tariff. The new requirements would apply to any small generating facility that executes an SGIA as of the effective date of the NOPR or takes any action that requires the submission of a new interconnection request after the NOPR’s proposed effective date.
Small generator owners and distributed generator manufactures are likely to push back on the notion that they have a major impact on the grid. They are also likely to argue that the extra costs they will incur to add ride through capability will act to reduce the economic benefits they currently enjoy and will negatively impact the continued development of distributed energy resources.