Thursday, February 21, 2019

MISO Details ‘Uncertainty’ Behind Winter Max Gen Event

By Amanda Durish Cook

CARMEL, Ind. — MISO proactively managed its eighth maximum generation event in six years last month despite the difficulty of pulling together the forecast leading up to the episode, RTO staff reported last week.

Ron Arness | © RTO Insider

Ron Arness, MISO director of Central Region operations, said “a significant amount of uncertainty” characterized the Jan. 30-31 event, spurred by a polar vortex bringing record cold conditions.

High load, fuel supply issues and the possibility of equipment failure coupled with substantial voluntary load management, such as school and business closings, made load profiles uncertain over the period, Arness said. MISO called the maximum generation event beginning 2:38 a.m. ET on Jan. 30 and terminated it at 11 a.m. the following day.

“We had some extreme temperatures … and because of the actions of you as members and MISO took, we reliably maintained service. It was essential because public safety was critical at that time,” Arness told stakeholders at a Feb. 7 Market Subcommittee meeting.

MISO originally forecasted a 104-GW peak load on Jan. 30, though the actual peak clocked in at 101 GW as temperatures sunk to -30 degrees Fahrenheit in some parts of the balancing area.

“We thought we were going to be short, and then we weren’t,” Arness said. “Even though temperatures were colder than we predicted, this voluntary load curtailment” scaled down load.

To produce its regional weather forecasts, MISO uses two separate third-party weather forecasters, both of which rely on multiple weather models.

MISO said that for much of the event, it experienced increased imports in response to its emergency conditions pricing. On Jan. 30, spot natural gas prices nearly doubled to $7.42/MMBtu and the average real-time LMP quadrupled to about $108/MWh. By Jan. 31, the real-time LMP dropped to about $49/MWh, still about double the energy price two days prior.

The RTO entered a cold weather alert on Jan. 25, an important and proactive step, Arness said. (See MISO Maintains Reliability Through Arctic Midwest Temps.)

“Really the intent of that cold weather alert is so members can update their offers and unit availability,” Arness said, stressing that MISO is better able to manage the market with the most accurate offer and commitment information.

“Thank you to all your companies that worked so hard to keep the lights on,” Chris Miller, of FERC’s Office of Energy Market Regulation, told members.

MISO max gen timeline | MISO

Winter Winds, but Few to Harness

MISO operators were further stymied by lower wind generation than expected during the arctic blast.

Wind output during the morning peak Jan. 30 was about 4 GW below forecast as the worst of the cold struck the Midwest. Wind output averaged 4.3 GW and 4.7 GW on Jan. 30 and 31, respectively, compared with about 13 GW for the two days prior to the event.

“It was cold and the wind was blowing, but we suspect that there were significant cold weather cutoffs. We did expect some cutoffs due to the cold — about 1 GW — but we didn’t expect this magnitude,” Arness said.

“This is something we have not seen since MISO has been in existence,” he added.

Arness said MISO staff will continue to investigate the drop in wind output, as well as other factors during the event. The RTO will review wind generator availability during cold temperatures, including maintaining a list of wind generators that have cold weather shutoffs installed, he said.

“What we’re looking for is lessons learned and to enhance our preparedness for future events,” Arness said.

LMR Data Forthcoming

All told, MISO requested about 2,500 MW worth of load-modifying resources during the event. LMR performance reports are expected later.

Stakeholders asked if MISO would consider decoupling its LMR dispatch from its emergency operating procedures so LMRs can be used outside of a declared emergency. Under MISO’s emergency procedures, LMRs are classified as emergency-only resources, requiring the RTO to declare an emergency before dispatching them.

Executive Director of Market Operations Shawn McFarlane said a December Tariff filing would allow MISO to issue scheduling instructions for LMRs as early as 12 hours ahead of a called emergency, allowing the resources to activate and be ready to deploy during an emergency.

Stakeholders questioned whether MISO remains confident about in that approach.

“We can’t deploy emergency resources when it’s not an emergency,” Executive Director of Market Development Jeff Bladen said.

Arness said MISO will continue to dissect the event with stakeholders in public meetings later in February and March.

Customized Energy Solutions’ David Sapper asked for a pricing analysis around the event, given that average energy prices two days before the event hovered around the usual $26/MWh and $27/MWh, even as temperatures ranged from -20 to 2 F.

MISO staff promised to return with more pricing information.

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