FERC was not persuaded by environmental nonprofits, utilities or Mississippi regulators to order MISO to rework the sloped demand curve it’s been cleared to use in the spring capacity auction.
The commission issued a Dec. 3 order, refusing all rehearing requests tied to the demand curve’s opt-out provision, elimination of a clearing price cap and the curvature itself (ER23-2977).
Starting in 2025, LSEs that decide to opt out of the auction and sloped demand curve must obtain more capacity than strictly necessary to meet MISO’s one-day-in-10-years system reliability standard. The rule is a feature of the new curve and applies an “X% adder” — which changes yearly — beyond strictly necessary load obligations in an attempt to create congruence between LSEs that participate in the auction and are subject to the sloped demand curve and LSEs that opt out of the auction by assigning them similar reserve requirements. (See FERC Approves Sloped Demand Curve in MISO Capacity Market.)
The Sierra Club, Natural Resources Defense Council and the Sustainable FERC Project argued over the summer that it’s unfair for the RTO to require utilities that opt out to procure capacity beyond resource adequacy needs. (See Environmental Groups Seek Rehearing of MISO Sloped Demand Curve.)
But FERC said it’s appropriate for MISO’s sloped demand curve plan to place a value on incremental capacity above a loss of load requirement. As such, the commission said LSEs that choose to opt out shouldn’t “be exempt from contributing to these incremental reliability benefits.”
“LSEs that opt out of the auction are not also opting out of the overall resource adequacy construct, which, as MISO notes, is crafted as a ‘risk-sharing pool across all LSEs, regardless of the LSE’s choice of participation model,’” FERC decided.
The commission pointed to a previous finding that “a downward-sloping demand curve provides a good indication of the incremental value of capacity at different capacity levels” and that “incremental capacity above the [reserve margin] is likely to provide additional reliability benefits.”
FERC said MISO’s opt-out as its stands neither motivates LSEs to participate in MISO’s voluntary capacity auctions nor incentivizes bowing out.
FERC disagreed with the nonprofits that MISO is obliged to offer a “truly compelling justification” before it forces LSEs to buy more capacity than necessary to meet its reliability targets. The commission also said it is not MISO’s concern if incremental capacity procured outside the auction is more expensive than incremental capacity procured within the auction — a theoretical argument of the nonprofits.
“While public interest organizations would prefer an opt-out mechanism that considers parity of cost of incremental procurement rather than parity of quantity, we do not need to evaluate the relative reasonableness of such a mechanism, given that we continue to find MISO’s proposed design to be just and reasonable,” FERC explained.
The commission also decided MISO remains free to terminate its current 1.75-times-the-cost-of-new-entry (CONE) annual price cap for local resource zones. Transmission-dependent utilities in the Midwest had argued that MISO should have preserved the annual cap to discourage excessive prices and protect consumers.
FERC’s refusal leaves MISO using a setup where the total annual price for a local resource zone could reach as high as four times the CONE, depending on whether capacity shortages occur in all four seasons of the auction.
FERC said the annual cap was necessary under the previous vertical demand curve because even an “extremely small,” 1-MW shortage could have prices shooting up to CONE in all four seasons. Conversely, FERC said the sloped curve should return more gradual increases in shortage pricing that are commensurate with the missing capacity quantities.
FERC said it’s “extremely unlikely” MISO would experience shortages in all four seasons, and if it did occur, the four-times-CONE clearing prices would properly reflect “unprecedented and severe capacity shortages.” The commission also dismissed as speculative the utilities’ argument that price protections are needed because a sloped curve would introduce the potential for more erroneous market results.
Finally, FERC rebuffed arguments from the Mississippi Public Service Commission that it shouldn’t have accepted the sloped curve because it supported MISO’s vertical demand curve in past dockets.
FERC said it never foreclosed MISO’s ability to adopt a sloped curve just because it found a vertical curve reasonable at the time and it “expressly left open the possibility that MISO could adopt a different market design if it so desired.”
FERC noted that in the past, it has found both sloped and vertical demand curves practical and said it did not “change course” from its precedent regarding a sloped versus vertical curve, as the Mississippi PSC suggested.
“Rather, this was the first instance in which MISO proposed a shift to a sloped demand curve design,” FERC said.