Co-located Battery Energy Storage Facilities and Solar Generation Assessed a Disgorgement of $381,724 and Civil Penalty of $105,000 by FERC Enforcement

Summary:

In December 2021, CAISO modified the CAISO Tariff to prohibit co-located battery facilities from deviating from dispatch instructions when providing ancillary services. With this modification, during the Relevant Period, CAISO Tariff § 34.13.3 stated, in relevant part: “A Co-located Resource that is a Non-Generator Resource may not deviate from a Dispatch Instruction pursuant to this section if it is providing Ancillary Services in the same Dispatch Interval.” Under Appendix A of the CAISO Tariff, a battery facility is considered a Non-Generator Resource.36.NextEra was unaware of CAISO’s December 2021 tariff change during the Relevant Period and thus did not update its software to comply with that tariff change. During the Relevant Period, when the combined output of a Plant’s battery and solar facilities approached the POI limit, the programmable logic controllers (PLCs) at the Plant that controlled the output of the solar and battery facilities automatically curtailed the battery facility, allowing the solar facility to continue to deliver its output to the CAISO grid, as was permitted prior to CAISO’s December 2021 tariff change. NextEra’s software did so even during intervals in which the Plants’ batteries received ancillary services awards.

Additional Discussion:

There were 3,835 five-minute intervals during which the Plants’ battery facilities deviated from dispatch instructions while holding ancillary services awards. On these occasions, the combined output of the Plants approached or met the shared POI limit, and NextEra’s software automatically curtailed the battery facilities instead of curtailing the solar facilities.

Violation

A Co-located Resource that is a Non-Generator Resource may deviate from a Dispatch Instruction where a co-located Eligible Intermittent Resource at the same Generating Facility is producing above its Dispatch Operating Target due to meteorological conditions such that the Co-located Resources’ combined output would exceed the Interconnection Service Capacity of the Co-located Resources, or otherwise threaten reliability or safety. Such deviations may only occur through proper control technologies that ensure the combined output of all Co-located Resources does not exceed the Generating Facility’s Interconnection Service Capacity. All deviations from Dispatch Instruction will be subject to Uninstructed Imbalance Energy. A Co-located Resource that is a Non-Generator Resource may not deviate from a Dispatch Instruction pursuant to this section if it is providing Ancillary Services in the same Dispatch Interval.

Enforcement determined that during the Relevant Period, the Companies’ Plants deviated from CAISO’s dispatch instructions while providing ancillary services during all or portions of 3,835 five-minute intervals, in violation of CAISO Tariff § 34.13.3.

Companies did so by curtailing their battery facilities (which constituted Non-Generator Resources under Appendix A of the CAISO Tariff) and allowing their co-located solar facilities to continue to deliver their output to the CAISO grid.

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