On July 21, 2016, FERC issued a final rule modifying the pro forma Small Generator Interconnection Agreement (“SGIA”) to require newly interconnecting small generators to “ride-through” voltage and frequency disturbances rather than disconnect from the larger transmission system. With this final rule, FERC obligates new small generators—those less than 20 MW—to have comparable ride-through capabilities as those imposed on large-scale counterparts through the pro forma Large Generator Interconnection Agreement (“LGIA”).
To ensure the reliability of the transmission system through voltage and frequency disturbances, FERC requires large generators to ride-through such events, rather than trip off-line and risk destabilizing the grid. FERC considered imposing similar requirements on small generators in 2005 when it first set out the pro forma SGIA in Order No. 2006, but ultimately declined to do so on the assumption that integration of small-scale wind and solar resources would have a minimal impact on the grid. The Commission again considered the question in 2013 through Order No. 792, but held-off to let the Institute of Electrical and Electronics Engineers (“IEEE”) complete the revision process for Standard 1547, its distributed resources interconnection standard.
FERC reopened the small generator ride-through question in March 2016 with a notice of proposed rulemaking (“NOPR”). According to the Commission, several changed circumstances have now brought this issue to the fore, including the increasing penetration of distributed energy resources, which the North American Electric Reliability Corporation has noted will adversely impact the electric grid if not carefully managed and coordinated. In addition, FERC emphasized recent technological advancements and interconnection standards—like smart inverters and the now newly revised IEEE Standard 1547—indicate that small generators are capable of riding through voltage and frequency disturbances.
In the July final order, FERC added new section 1.5.7 to the pro forma SGIA, which requires frequency and voltage ride-through capabilities for newly interconnecting small generators taking service under an open access transmission tariff (“OATT”). The Commission declined to reference specific technical standards in the new section 1.5.7, but rather, set out basic performance expectations to give transmission operators flexibility. Additionally, FERC sided with other participants arguing for regional variations for Independent System Operators and Regional Transmission Organizations that may operate under slightly different reliability requirements as a result of their resource mix. Lastly, the Commission rejected calls by some commenters to delay the proceeding pending further vetting of new technologies, stating that there was a “pressing need” to instate these requirements considering the increasing penetration of small generators onto the transmission system. Ultimately, the Commission concluded, the time was ripe for instituting these requirements, to equalize the treatment of large and small generators, and set “a national minim ride through capability before future increases in deployment of small generation facilities.”
A more detailed version of this post first appeared on the Troutman Sanders’ Washington Energy Report.