Leadership of the Western EIM on Sept. 8 approved a new category of market participant known as a "sub-entity," a measure deemed necessary to implement Public Service Company of Colorado's entry into the imbalance market.
The new rule applies to balancing authorities outside of the California ISO. The EIM Governing Body approved ISO management's proposal, which allows utilities within a balancing authority area controlled by a separate EIM entity to financially settle load and nonparticipating-resource imbalance energy directly with CAISO instead of with the EIM entity.
EIM sub-entities will also submit base schedules directly to the ISO, and potentially submit forecast, outage and network model information directly to the ISO, according to a CAISO memorandum.
The proposal "establishes a new EIM sub-entity scheduling coordinator relationship through contractual and tariff provisions that separate the EIM sub-entity functions from the EIM entity functions," CAISO said in the memo. The measure still requires approval from the CAISO Board of Governors and FERC.
Under current rules, the ISO settles load imbalance energy at the balancing authority level with the EIM entity that operates the balancing authority area. Utility loads in the BAA are settled with the EIM entity under its open-access transmission tariff.
As part of its EIM implementation agreement for PSCo, the ISO committed to developing a new category of market participant to enable utilities within a BAA operated by another entity to directly settle load and nonparticipating supply-resource energy imbalances with the ISO. The new rules are a result of that process, CAISO said.