Frequency Control Requirements for Reliable Interconnection Frequency Response

In light of changes in how electricity is being both generated and consumed, the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) has written a new report analyzing challenges facing the nation’s electric grid and making recommendations for ensuring continued reliability. The report was prepared for the Federal Energy Regulatory Commission (FERC), Office of Electric Reliability, to support ongoing FERC and industry efforts to ensure reliable interconnection frequency response for the three major interconnections in the United States: the Eastern, Western, and Texas Interconnections. The purpose of this study (and its supporting supplemental reports) is to support policymaker and industry understanding of the physical requirements for reliable interconnection frequency response, which is the collective ability of the power system to respond to sudden loss events, such as the loss of a large generator. Grid reliability depends on controlling the power system frequency so that it remains within pre-established, safe operating bounds. Reliability is threatened when a large electric generator or generators experiences a problem and automatically disconnects from the power system; the loss of generation causes an immediate decline in power system frequency. If the remaining, still-connected generators do not respond and rapidly arrest the decline in frequency, power system frequency may decline below established, safe operating bounds and trigger automatic, emergency load shedding to avoid a cascading blackout. The study builds on an earlier study for FERC conducted in 2010