By Amanda Durish Cook
The tamest winter in recent memory brought no emergencies for MISO, though the RTO’s South region was the subject of three weather-related alerts.
Speaking during a teleconference of the Board of Directors’ Markets Committee on March 24, Executive Director of Market Operations Shawn McFarlane said the winter resulted in “minimal drama” over the three months.
He said MISO’s “lowest winter peak in recent years” was driven by relatively high temperatures. Winter load peaked early at 96 GW on Dec. 19, far short of the forecasted 104 GW. While Midwest region temperatures were higher than average, the South region experienced temperatures about 4 degrees lower on average than in early 2019.
McFarlane said low gas prices and smaller load brought a 28% decrease in prices from last winter. Real-time LMPs averaged $21/MWh, down 28% from last year’s $29/MWh winter average.
“This is about as low as we’ve seen gas prices since they were deregulated in the ’80s,” Independent Market Monitor David Patton said. “It’s fundamentally changing MISO’s dispatch.”
MISO declared just one maximum generation alert for its South region, on Feb. 21, when cold weather in the Southeastern U.S. caused tight conditions.
McFarlane said in addition to the cold that morning, three major long-lead generation units failed to come online, dropping the operating margin to 500 MW, which triggers a maximum generation alert. The no-shows led MISO to call up all area short-lead units. He said two of the three long-lead units eventually started.
“The alert was only in effect for 90 minutes to cover the morning peak from 7:30 to 9 a.m. We weren’t at risk of not being able to serve load,” McFarlane explained.
MISO South was also the subject of two separate severe weather alerts as tornados and heavy rain hit the region Dec. 16-17 and again Jan. 10-11.
MISO also set a new all-time wind generation peak of 18 GW on Feb. 22.
“It seems like it occurs every season other than summer,” McFarlane said of wind peaks.
However, McFarlane said MISO also experienced a “nearly zero” wind output from Jan. 28-30, illustrating the need to continue the resource availability and need projects to better manage the intermittent nature of renewable resources. (See MISO Forward Report Stresses Near-term Change.) Altogether, the three days brought 39 hours of wind production below 200 MW.
Lake Erie Loop Flows Re-emerge
MISO’s winter prices were impacted by loop flows on lines around Lake Erie that are not being controlled through phase angle regulators, Patton said.
According to the Monitor, Ontario’s Independent Electricity System Operator (IESO) throughout January and February requested transmission loading relief (TLR) on the Michigan-Ontario interface related to the loop flows. IESO’s requests resulted in PJM curtailing about 162 GW worth of exports to MISO across 80 hours in the winter, Patton said.
“Now that’s a really big deal. That’s like losing two nuclear units. MISO doesn’t plan for this,” Patton said. “This is hugely costly to MISO when IESO takes these actions.”
As a result, Patton said hourly market-wide energy prices exceeded $370/MWh, and market participants that had scheduled imports from PJM in the day-ahead market lost about $3.5 million collectively.
Patton said he’s concerned that it appears IESO is calling for relief not because the Michigan-Ontario interface is overloaded, but because the PARs aren’t enough to control the loop flows.
“It’s important for IESO to tighten down and only take these actions when they’re warranted,” Patton said.
He said MISO is in discussion with IESO, PJM and NYISO about the appropriate criteria to call for TLR.
“This is an ongoing issue that we’ve been struggling with for years,” MISO President Clair Moeller told board members. Unscheduled loop flows around the Lake Erie region have been a problem since the late 1990s. (See MISO not Allowed to Allocate Lake Erie PARs Costs to PJM and NYISO.)
MISO management said it plans to examine IESO’s TLR requests to see if there may be a means to mitigate their frequency.
