MISO has FERC’s go-ahead to bar its renewable energy resources from supplying ramping reserves.
FERC’s Thursday order leaves MISO’s dispatchable intermittent resources (DIRs) ineligible to provide ramping service beginning Sept. 1 (ER23-1195). (See MISO Plans to Bar Intermittent Resources from Ramp Capability; MISO Defends Renewable Ramping Stance to FERC.)
FERC said MISO’s plan doesn’t amount to undue discrimination because it “currently faces operational and price formation challenges associated with DIRs being unable to deliver ramp capability products services in the vast majority of intervals that DIRs are cleared.”
A group of MISO transmission customers argued FERC should have rejected the filing because the ban will treat similarly situated resources differently.
A coalition of MISO’s clean energy advocates also protested MISO’s plan on the same grounds and said the commission had a duty to reject it because it would create a rate that “unduly discriminate[s] among resources’ eligibility to provide grid services.” The group also said that MISO is “rapidly approaching an inflection point where it may be economic for renewable generation to maintain headroom in order to provide ramp capability products.” They said that prohibiting DIRs from providing ramp service conflicts with “MISO’s admitted need for greater flexibility” over the next two decades.
MISO has said its proposal is necessary — at least for now — because of the “significant differences” between renewable and non-renewable resources’ ability to deliver ramp product. It said most of DIRs’ cleared ramping capability is uneconomic and cannot be delivered because it’s trapped behind transmission constraints. The MISO ramp capability product’s current design doesn’t account for a resource’s deliverability.
“Given these conditions, we find that the proposed tariff revisions are just and reasonable and not unduly discriminatory or preferential as they will allow MISO to procure ramp capability products from only those resources that can reliably deliver them,” FERC decided.
FERC said that accepting MISO’s proposal will put a stop to DIRs being paid for ramp service “even though DIRs cannot reliably deliver the product 99.7% of the time.” It also said it will end some market distortion because MISO’s market clearing software will be able to clear resources other than DIRs that can provide deliverable ramping.
MISO’s Independent Market Monitor agreed that DIRs are “virtually always undeliverable” when scheduled to furnish ramping up capability.
The Monitor said, “ideally, MISO would automatically disqualify any resource from being scheduled to provide ramp capability products when it is not deliverable, but that is not technically feasible for MISO today or in the near future.”
In a joint concurrence, Chair Willie Phillips and Commissioner Allison Clements wrote to “emphasize the narrow, fact-bound nature of these decisions.”
Phillips and Clements said FERC’s decisions hinges on a “near perfect overlap between DIRs’ undeliverability and the circumstances when DIRs would clear ancillary services.”
“Today’s orders depend upon the particular factual circumstances before us, that unlike non-DIRs, DIRs are highly unlikely to be able to provide ancillary services when they are cleared,” the two wrote. They said ramping trends and circumstances could change in the future as MISO adds more renewable energy and advised MISO to improve its markets software so it can account for transmission constraints.
