CAISO has launched an “expedited” initiative to address stakeholder concerns about how the Extended Day-Ahead Market (EDAM) will allocate congestion revenues when a transmission constraint in one EDAM balancing authority area causes congestion in a neighboring BAA.
The issue came to light in February when Powerex published a paper contending that EDAM contains a “design flaw” that could subject non-CAISO market participants to $1 billion in unfair congestion-related charges that would be conveyed as payments to participants operating within the ISO. (See Powerex Paper Sparks Dispute over EDAM ‘Design Flaw’.)
The problem will arise when a transmission constraint in one system “parallel” (or loop) flows on a neighboring system, the Vancouver, leaving the latter system — and its transmission users — to carry the costs of unexpected congestion, the Canada-based electricity marketer said.
The paper argued that EDAM’s treatment of firm transmission rights and congestion would leave that market’s non-CAISO participants exposed to charges for constraints occurring outside their systems while failing to provide the ability to recover or hedge against those costs — something the company called an “aberration” among organized electricity markets.
Powerex, which owns transmission rights throughout the West, said the PacifiCorp, NV Energy and Idaho Power BAAs would be most exposed to the issue, including when those utilities use their own transmission to deliver their own generation to their own load.
The company identified the issue after reviewing the revised Open Access Transmission Tariff (OATT) PacifiCorp filed with FERC in January to reflect its impending participation in EDAM, and other entities since have filed comments in that docket (ER25-951) expressing similar concerns.
CAISO and PacifiCorp representatives initially responded sharply to Powerex’s assertions, calling the paper “misinformed and inflammatory.” But the new initiative indicates the ISO is taking the congestion issue seriously, even if it and EDAM supporters point out the issue is the byproduct of overlaying elements of an organized electricity market on the legacy OATT system.
During a March 24 workshop to kick off stakeholder engagement for the initiative, CAISO staff presented an alternative method for calculating the allocation of certain congestion revenues under EDAM, with meeting participants raising concerns about long-term effects of the proposed method and asking for more clarity.
CAISO outlined the proposed new method in a March 17 issue paper, which was reviewed in detail at the meeting. The alternative method would be “transitional” and would be informed by newly identified patterns of congestion as EDAM adds other balancing areas, Joanne Serina, CAISO vice president of stakeholder engagement and customer experience, said at the meeting.
The ISO has cleared its calendar over the next two weeks to make room for the expedited initiative, Serina said. The accelerated timeline reflects CAISO’s desire to prioritize stakeholder feedback on EDAM issues, she said.
“We are wholeheartedly committed to working with stakeholders to come to an equitable solution,” Serina said.
CAISO could, as early as May, approve the alternative method, develop a different alternative or decide to keep the existing one.
Question of Intent
The primary question in the initiative is whether certain congestion revenues should be allocated to the balancing area in which the congestion revenue accrued, or to the neighboring EDAM balancing area where the transmission constraint is located.
Under existing design, the latter is true: EDAM is set to allocate congestion revenues to the BAA in which an internal transmission constraint is located. This approach has been approved by FERC and implemented for the past decade in the WEIM, and it is the practice today.
The current congestion allocation approach follows cost-causation principles under which congestion revenues flow to the transmission constraint location. This is because the BA with the constraint must pay for and manage the constraint, CAISO said in its paper. Transmission constraints determine in part the congestion price at a pricing location, and congestion revenues then are allocated back to energy market participants, according to the paper.
However, under the alternative design, congestion revenues associated with parallel flow schedules would be allocated to the BA where the congestion revenue accrued, not the neighboring balancing area where the constraint is located, the paper says.
In the paper, CAISO said allocating congestion revenues to EDAM balancing areas based on where they are collected will “enable a more complete sub-allocation of congestion revenue from the EDAM balancing area to transmission customers exercising firm Open Access Transmission Tariff (OATT) transmission rights within their balancing area.”
The alternative approach could increase or decrease the total congestion revenue available for sub-allocation to a balancing area, CAISO wrote. The EDAM area is not managed as a single balancing area or under one transmission tariff, so CAISO must determine what amount of congestion revenue is to be allocated to each EDAM balancing area, according to the paper. A balancing area then allocates revenues based on their specific tariffs.
CAISO at the March 24 meeting responded to numerous questions and concerns about the alternative design. Many participants asked for clarification on the methodology and examples in the issue paper, while others looked for more information on potential impacts on the power system and suppliers.
“What do you mean when you say, ‘Managing a constraint in an area’?” PacifiCorp commercial transmission manager Rohan Chatterjee asked at the meeting.
CAISO regional markets sector manager Milos Bosanac responded: “Depending on the nature of the constraint, there may be additional steps that the balancing area may need to take. Predominantly, there will be dispatch effects associated with a constraint.”
Jeff Spires, Powerex’s director of power, said his company is concerned that an alternative option would be transitional without agreement on the “guiding principles” around the future evolution of the markets.
“I agree [with] letting the markets evolve … but at the same time, I would expect the opportunity to determine what principles are needed to provide that long-term confidence. Until we get to a full RTO world, these markets need to be compatible with that framework.”
Speaking at a March 25 meeting of the Western Energy Markets (WEM) Governing Body, member Anita Decker said she recognized there would be “bumps in the road” with the rollout of EDAM.
“But I think the important thing here is the intent, and the intent is to end up with a strong market, at the end of the day, for everyone that’s participating — and I think that intent really goes a long way to build confidence,” Decker said.
“I just want to reinforce our commitment to making this transition from traditional OATT to a marketplace as smooth as possible, and that’s why I think we’re taking up this initiative and trying to find that path forward,” CAISO COO Mark Rothleder said at the WEM meeting.
Stakeholder comments on the initiative are due by April 7. CAISO plans to publish a full proposal April 14, with the final proposal presented for decision by the ISO Board of Governors and WEM Governing Body at their May 20-22 meetings.