Assessing Potential Risks to the Bulk Power System from Older Inverter-based Distribution Generation

NARUC undertook a study to assess potential risks to the distribution system from older inverter-based distribution generation. Using data from ISO-NE and individual New England states, the analysis identified ~160,000 legacy DER sites totaling ~4,400 MW across the ISO-NE area. The study finds that these legacy inverter-based sites could pose a rise to bulk power system reliability but that ISO-NE’s reliability assessments are not robust enough to draw firm conclusions regarding the needs for reconfiguration of legacy distributed energy resources (DERs) to reduce risk. Results were presented in a webinar to New England regulators.