Hot this summer? Here’s how the power grid is handling it

Heat waves have rippled across the United States this summer, pouring hot, humid air into regions throughout the country. More than 100 million people were under heat-related warnings and advisories last week. Over this weekend and into Tuesday, the “feels like” temperatures were expected to reach the triple digits in Midwestern states.

The record-breaking summer warmth spurs sweaty communities to crank up their air conditioners — and power grids are straining.

Iowa’s energy, along with that of 14 other states and a Canadian province, is managed by Midcontinent Independent System Operator — commonly known as MISO. According to an energy reliability assessment from a nonprofit regulatory authority released in May, MISO is at “high risk” of energy emergencies this summer because of anticipated energy shortfalls in its north and central regions.

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What does that mean, and how has that played out this summer so far? Here’s what you need to know about how your energy is faring against the sweltering heat.

Why is MISO projected at ‘high risk?’

In April, MISO announced a projected energy shortfall between the 11 Midwestern states within the organization’s north and central regions amid “warmer-than-normal temperatures.” The utilities between Zones 1 through 7 — including parts of Iowa — couldn’t offer enough energy to meet the summer peak forecast of 124 gigawatts.

“We’ve been seeing this trend for the last few years, but this year’s summer assessment and capacity auction reflect the potential for the tightest conditions we’ve experienced,” said MISO spokesperson Jay Hermacinski. Capacity auctions are when MISO members disclose how much energy they can provide in order to meet demand.

The 1.2-gigawatt deficit in meeting the peak demand forecast can be rectified by importing power from other regions or by “managing the load” — that is, decreasing energy demands through voluntary programs that curtail customers’ energy usage in exchange for cheaper rates. But the shortfall puts consumers in those regions at slightly higher risks of temporary outages.

These increased risks come as the electric grid endures “a transformation never before seen,” Hermacinski said.

Readily available fossil fuel generation, like coal, is being replaced by weather-dependent renewable resources that can’t operate 24/7. In Eastern Iowa, for instance, Alliant Energy’s Lansing Generating Station will be retired by the year’s end and replaced by increasing wind and solar generation.

This renewable energy is cheaper and more environmentally sound than fossil fuels — but there needs to be transmission line upgrades to ensure its dependability across the grid, said Ian Dobson, an engineering professor at Iowa State University.

MISO consumers are also using more electricity for their heating needs and electric vehicles, changing daily and seasonal peak energy demands. And, all the while, more frequent and severe extreme weather is increasingly battering the grid.

“You must be very aware of the climate change kind of worsening of extreme weather,” Dobson said. “That is an issue for the electricity supply.”

Extending the transmission system that crisscrosses throughout MISO’s regions is one element of the organization’s plan to address the changing energy landscape. Its first long-range transmission portfolio will be proposed to the MISO board of directors next week, Hermacinski said. The plan includes 18 transmission projects throughout MISO’s north and central regions, with a price tag of $10.3 billion.

What has happened this summer so far?

During the week of June 21, when a massive heat wave crossed the country, MISO announced a warning that challenging conditions were expected due to high electricity demands from the hot weather. The declaration required utilities to delay any nonessential equipment maintenance and to prepare emergency resources.

Similar emergency alerts preceded and followed this announcement throughout this summer, asking members to keep an eye on grid conditions. Since the start of May, MISO has issued the following alerts and advisories (along with extensions) that include Iowa:

MISO also issued one maximum generation warning on May 12 that included Iowa — a step up from alerts and advisories.

This notification prepares operators for the possibility that energy supplies may fall below normal operating practices. It isn’t until a maximum generation event — the second step of MISO’s emergency event levels — that there’s an actual shortfall where energy supply is less than demand.

Even with the alerts, warnings and challenges infiltrating the power grid, Iowans shouldn’t fear their power to be involuntarily shut off. MISO hasn’t gotten close to a maximum generation event this summer, Hermacinski said.

“This does not mean consumers should expect the lights to go out in the MISO region this summer,” he said. “The overall stability and reliability of the system will not be compromised, as MISO will continue to implement any actions that may be necessary to prevent uncontrolled, cascading outages.”

Why is Iowa at a low risk for power outages?

Within MISO’s staircase of increasing emergency event levels, the last resort is load shedding: the rare occasions when controlled power outages are enacted to protect the grid system.

Load shedding has never plagued MISO’s north and central regions. The worst-case scenario of rolling blackouts, which are uncontrolled outages, has occurred only once for MISO during the 2003 Northeast blackout. (Power outages during destructive natural disasters, like the 2020 derecho, were due to infrastructure damage, not energy deficiencies.)

That’s thanks to MISO’s sheer size and amount of members that generate and transmit power, ISU’s Dobson said.

“The chance of a blackout is not zero — ever — even under good conditions,” Dobson said. “But there’s always variability that you’re handling, and people are handling it. That’s why we’re all connected together.”

The power grid in Texas — which was crippled by the infamous 2021 winter storm — experiences higher risks of outages and blackouts because most of its energy is transmitted over a relatively small transmission grid, said Leigh Tesfatsion, an economics professor at Iowa State University. As high temperatures across the region prompt more electricity usage for air conditioning, the surge in power demand could “overload” the smaller system.

In contrast, since Iowa is part of a much larger transmission grid, it’s unlikely that high temperatures would plague the entire large region, Tesfatsion said. Thus, power can be imported throughout the grid to areas in need — a useful “insurance pool” for consumers.

“That's why having these big interconnections and transmission capability facilitates renewables,” Dobson said. “One of the most ecologically sound things to do, or sustainable things to do, is to invest in the transmission system.”

The combination of events that would cause MISO to enact controlled outages, thus surpassing the first four stages of its emergency event levels, is unlikely, said James McCalley, an electrical engineering professor at Iowa State University.

“It is not possible to say anything about what a power grid will see in the future with 100 percent certainty,” McCalley said. “But I think it more likely that we will not see anything close to a blackout this summer.”

Brittney J. Miller is an environmental reporter for The Gazette and a corps member with Report for America, a national service program that places journalists in local newsrooms to report on under-covered issues.

Comments: (319) 398-8370; brittney.miller@thegazette.com