CAISO on April 17 released a draft final proposal detailing how its Extended Day-Ahead Market (EDAM) will allocate congestion revenues in circumstances when a transmission constraint in one balancing authority area produces “parallel” flows — with resulting transmission congestion — in a neighboring BAA also participating in the market.
The draft proposal is the product of an “expedited” stakeholder process the ISO kicked off in March to address concerns among some Western electricity market participants that EDAM would leave some non-CAISO participants exposed to congestion charges for constraints occurring outside their systems, while not providing them the ability to adequately recover or hedge against the charges. (See Fast-paced Effort will Address EDAM Congestion Revenue Issue.)
“This proposal for parallel flow congestion revenue allocation is an initial step toward continued evolution of the overall congestion revenue allocation design informed by market operational experience and stakeholder input,” CAISO said in the proposal.
Vancouver, Canada-based electricity trader Powerex first called attention to the issue in a February paper contending that EDAM’s handling of congestion revenues represented a “design flaw,” which the company identified after reviewing PacifiCorp’s proposed revisions to its open access transmission tariff intended to accommodate its participation in the market, scheduled to begin in 2026. (See Powerex Paper Sparks Dispute over EDAM ‘Design Flaw’.)
Powerex is a firm OATT rights holder in PacifiCorp’s system, and it argued that any such transmission customer stands to lose value in its contracts under the arrangement.
Seeking Balance
CAISO said its draft proposal seeks to strike a balance between EDAM’s existing FERC-approved rules related to congestion revenues and the alternative scheme it floated in the issue paper kicking off its expedited stakeholder initiative.
Under EDAM’s existing rules, congestion revenues are allocated to the BAA containing a constraint, with the operator of that BAA allowed to sub-allocate any revenue it receives from the ISO to transmission customers according to the procedure outlined in that BAA’s OATT.
“This congestion allocation method recognizes that the balancing area where the internal transmission constraint is located bears the effects of that congestion and the reliability impacts associated with the constraint, and thus congestion revenues accruing across the interconnected EDAM footprint associated are allocated fully to the EDAM balancing area where the constraint is located,” CAISO notes in its proposal.
The ISO said many stakeholders “saw merit” in the existing design but “also recognized the concerns expressed with parallel flow congestion revenue allocation” and the need to develop a new “transitional” approach for allocating revenues “to support the ability to more readily protect or manage congestion cost exposure for OATT transmission rights holders.”
But stakeholders also expressed concerns about the potential alternative outlined in the issue paper, which proposed to allocate congestion revenues only to the BAA in which the revenues accrued, not to the neighboring area where the constraint was located. Some commenters thought the alternative went too far in reallocating the revenues, while others worried the approach could increase incentives for some transmission users to self-schedule generation to gain a more complete hedge, which would reduce the efficiency of market operations.
CAISO said its proposed design instead “leverages elements of the transitional alternative introduced in the issue paper and retains aspects of the current, FERC-approved, design to congestion revenue allocation; i.e., it is incremental to the underlying congestion revenue allocation methodology.”
Under the draft final proposal, parallel flow congestion revenues collected in an EDAM BAA that result from a binding constraint in a neighboring area will first be allocated to the BAA in which the overflow congestion occurs — and the revenues are collected. That will enable that BAA to distribute funds to firm OATT transmission rights holders who possess long-term and monthly point-to-point (PTP) and network integration transmission service (NITS) rights and have submitted “day-ahead balanced source/sink schedules.”
“Consistent with the existing EDAM design, transmission customers will register their firm PTP and NITS transmission rights, with the market operator identifying the nature of the rights from source to sink. These registered transmission rights will be associated with a contract reference number, which, when included in the bid submission, associates that bid with existing OATT transmission rights,” the proposal states.
The plan also stipulates that any remaining congestion revenues associated with the parallel flows would be allocated to the EDAM BAA in which the constraint occurred.
“This aspect of the design mitigates the concerns expressed by stakeholders that, under the transitional alternative described in the issue paper, balancing areas may be exposed to congestion costs (negative congestion revenues) associated with parallel flow effects when generation in the balancing area provides counter flow benefit to the direction of the transmission constraint located in a neighboring balancing area,” according to the proposal.
Additionally, EDAM would continue to allocate any congestion revenues that accrue within the BAA containing the constraint to that BAA, “consistent with the FERC-approved EDAM framework.”
Acknowledging “the complexity of the overall topic of congestion revenue accrual and allocation,” the proposal provides multiple illustrated examples of how the plan would work in practice.
‘Guns Blazing’
CAISO is moving quickly to wrap up the congestion revenue allocation proposal in time for a vote next month by its Board of Governors and the Western Energy Markets (WEM) Governing Body.
WEM stakeholders appear to largely on board with the ISO’s sense of urgency.
During an April 9 meeting of the WEM Regional Issues Forum (RIF) in Portland, Ore., representatives from most RIF sectors cited congestion revenue allocation as CAISO’s top priority right now, at the forefront of other issues the ISO will need to address to ensure a smooth launch of EDAM in 2026.
“We support moving quickly in the congestion revenue allocation initiative,” Vijay Singh, senior organized markets analyst at PacifiCorp, said on behalf of the RIF’s EDAM sector. PacifiCorp will be the first utility to begin participating in the EDAM next spring.
“We were really ready to come in guns blazing and go after the ISO for not doing more on congestion, but we really got to commend the ISO for kicking off the process and looking to go to the Board of Governors by May,” Avangrid’s Scott Olson said for the Independent Power Producers and Marketers sector.
The Bonneville Power Administration’s Allie Mace, RIF liaison for the Power Marketing Administration sector, also commended CAISO for moving on the issue, but she noted the “transitional” nature of the proposed solution and encouraged the ISO to include an initiative for longer-term solutions in its policy initiative road map.
CAISO will hold a stakeholder meeting to discuss the draft final proposal April 23.