By Amanda Durish Cook

MISO announced on Friday it had changed four elements of its proposed forward capacity auction, prompting renewed calls from some stakeholders to delay a FERC filing planned for Nov. 1.

RTO officials — who described the changes as a “refinement” to a “limited set of design elements” — insisted the filing will be made as scheduled.

On an Oct. 21 Resource Adequacy Subcommittee conference call, MISO revealed it had adopted the Independent Market Monitor’s suggestion to incorporate a pivotal supplier test in the forward auction for the RTO’s retail-choice regions.

Officials also said they will include a three-year forward peak load contribution calculation and modify the design’s materiality test, congestion calculation and cost allocation.

Pivotal Supplier Test

The pivotal supplier test would allow the Monitor to identify resources inside or outside MISO’s footprint that are large enough to affect market outcomes. Suppliers identified as pivotal would be subject to the RTO’s existing physical and economic withholding provisions.

Dynegy’s Mark Volpe said that while the Monitor “should certainly suggest marketing monitoring measures,” the pivotal supplier test had not been explored in the stakeholder process and was not simply a “tweak.” He asked for a conference call with the Monitor prior to Nov. 1 to discuss the test. MISO staff said that was unlikely to happen.

Congestion Charges

Under other changes, MISO would allocate congestion charges resulting from the clearing of infeasible resources to buyers rather than sellers as originally proposed. Officials said the change was made to avoid discouraging sellers’ participation in the auction and to align the cost allocation with other FERC-approved capacity markets.

The RTO also said it will limit congestion charges in the forward auction to situations in which constraint changes lead to a less than one-day-in-five-years loss-of-load expectation. MISO’s prior draft allowed congestion charges to occur anytime a locational constraint binds and proved more restrictive under the forward auction than the prompt Planning Resource Auction. The change will maintain the relationship between the variable reliability target and the quantity of capacity procured for competitive retail demand, MISO said.

Consumers Energy’s Jeff Beattie noted that MISO’s retail-choice areas are “heavily interconnected” and said he doubted the new cost allocation would ever occur.

Jeff Bladen, executive director of MISO market services, agreed that new congestion costs would only occur under “extreme circumstances” when incremental resources are need to step in for megawatts that cannot be delivered.

“In a sense, it’s a replacement charge because the constraints modeled need to be changed,” Bladen said. He said the charge is needed because MISO “can’t guarantee feasibility three years into the future.” He noted that ISO-NE, NYISO and PJM use a similar method.

Peak Load Contribution

The addition of a peak load contribution calculation was intended to “alleviate retail customer risk from their purchase/offer obligations” in the forward auction against any PLC changes that take place in the PRA, MISO said.

Bladen said the PLC provides “equal footing between demand and supply resources that enter into the forward auction.”

Materiality Test

The materiality threshold determines whether local resource zones will be included in the forward auction. It will be used in Michigan and Wisconsin, where the zonal boundaries traverse state lines.

The original proposal would have determined materiality based on the potential impact of competitive retail demand on the systemwide LOLE and could change from year to year.

Under the revision, MISO would determine materiality based on the greater of the LOLE impact and a fixed percentage (0.5%) of the systemwide planning reserve margin requirement.

MISO said the change provides a “reasonable balance” between reliability and certainty.

Filing Delay Sought

Several stakeholders asked for a delay in the filing to better understand the latest changes.

“This congestion charge is just not clear yet,” Indianapolis Power and Light’s Ted Leffler said.

Minnesota Public Utilities Commission staffer Hwikwon Ham said he wasn’t yet comfortable with wording on the Tariff changes.

RASC Chair Gary Mathis said if the subcommittee demanded a filing delay, it would only be taken under advisement by MISO. The next scheduled meeting of the RASC will be held on Nov. 2, a day after MISO’s projected filing date.

Bladen said MISO is “very proud of how the proposal has evolved and the balance it strikes.”

“Thanks for your comments and contributions,” he said.