CARMEL, Ind. — MISO last week continued to defend its decision to export power to its neighbors that played a role in tipping the RTO into emergency procedures during the December winter storm.
Staff told stakeholders their emergency operating procedures allow MISO to deploy load-modifying resources to “assist neighbors who are in a comparable or worse operating state.” The RTO exported up to 5 GW at times Dec. 23 to SPP, the Tennessee Valley Authority, Associated Electric Cooperative Inc. and the Southeast planning region.
“So, we did meet that condition during [Winter Storm] Elliott,” John Harmon, senior director of operations support, said during a Reliability Subcommittee meeting on Feb. 28.
MISO entered a three-hour maximum generation event during Dec. 23’s evening hours. Staff and stakeholders debated the lengths the grid operator should go to assist neighbors at the expense of its own reliability and adverse pricing impacts. (See MISO Actions During December Storm Spark Debate, MISO Data Show Steep Gas-fired Outages During Winter Storm.)
Market design adviser Dustin Grethen said MISO was able to partly repay its neighbors after years of relying on neighboring regions’ exports during various maximum generation events.
“It’s good to know that we can sometimes step in and help others when it’s necessary,” he said during a Market Subcommittee meeting on Thursday.
The RTO experienced operating reserve deficits on Dec. 23 and hit its $3,500/MWh price cap during several intervals.
MISO energy and operating reserve pricing on Dec. 23 | MISO
“There was plenty of pain all around tied to the pricing,” Grethen said.
MISO Executive Director Market Operations J.T. Smith said MISO, PJM and TVA all missed on load forecasts “in pretty outstanding fashion.”
Smith said MISO’s Independent Market Monitor will likely propose that the grid operator create joint operating agreements with the TVA and other nearby non-RTO members so that it can hold its own load harmless from exports’ pricing impacts.
“I strongly support what MISO did, but I think there needs to be some way to make whole the load that was exposed,” Minnesota Public Utilities Commission staffer Hwikwon Ham said.
Grethen said high prices during the event drove higher settlements and thus “higher credit exposures,” but MISO was able to work with its market participants to avoid any defaults.
MISO said its credit team ultimately issued 101 exposure warnings. It issues such warnings when a market participant’s exposure is greater than 90% of its combined posted collateral and credit line.
The storm resulted in $23 million of price volatility make-whole payments charged to load-serving entities. That was offset by $54 million of revenue neutrality uplift credits because of revenue surpluses from load, unit and export deviations in the real-time market. A net uplift of $32.4 million was credited to load-serving entities in the footprint, distributed through a load ratio share. MISO uses its revenue neutrality uplift mechanism to balance charges and credits, ensuring it remains revenue neutral across operating hours.
The grid operator said it plans to improve how it communicates emergency alerts to its market participants. Some stakeholders complained they didn’t receive notifications until after the event unfolded.
Other than the December emergency, “winter continues to be mild,” Harmon said.
MISO averaged 75 GW of load in January, with load peaking at 93 GW Jan. 31. It had projected peak demands of 102 GW under typical winter conditions and 109 GW should an arctic blast descend on the footprint. (See MISO: Diminished Emergency Possibilities this Winter.)
