Grid operators expect record electricity demand amid extreme heat

A heat wave across the central United States is leading electric grid operators to prepare for tight operating conditions and record electricity demand this week.

Carmel, Ind.-based regional transmission organization Midcontinent Independent System Operator (MISO) is expecting record load peaks for Wednesday and Thursday that exceed 128 gigawatts. MISO’s record peak was 127 gigawatts set on July 20, 2011. MISO manages the grid in the Canadian province of Manitoba and 15 U.S. states, including part of Arkansas.

Little Rock-based regional transmission organization Southwest Power Pool (SPP) set a record Monday afternoon (Aug. 21) when electricity demand peaked at 56,184 megawatts. The previous peak was 53,243 megawatts set on July 19, 2022. SPP manages the grid for 14 states, including a portion of Arkansas.

Both SPP and MISO have issued advisories to their member utilities about the extreme heat and tight operating conditions. According to MISO, it “preemptively notified all local utilities in its operating footprint to prepare every available resource to serve the projected load.” Its advisory is in effect until Thursday (Aug. 24) but may be extended if necessary.

Brandon Morris, advisor of strategic communications for MISO, said it expects the same operating conditions across its entire footprint.

MISO is working with its members and neighboring grid operators to ensure electricity generators and transmission lines are available for use as much as possible. This might require rescheduling planned generation and transmission outages, returning transmission lines to service and recalling power generators from planned outages. SPP has taken similar steps.

“We anticipate challenging operating conditions throughout the entire week, and we will need every available resource at some point,” said Jessica Lucas, MISO’s executive director of system operations. “We have issued several alerts and advisories based on the weather forecast. More emergency procedures may be required to keep the power flowing. That’s typical for a weather event like this.”

On Tuesday (Aug. 22), SPP issued a conservative operations advisory until 8 p.m., and its territory remains under a resource advisory until 8 p.m. Friday (Aug. 25). The advisories don’t require the public to conserve energy.

“We may move in and out of various advisories and alerts during this period of higher-than-average temperatures,” said Derek Wingfield, manager of communications and stakeholder affairs for SPP. “While we can’t rule out the possibility that we’ll escalate to a more severe energy emergency alert, we don’t currently anticipate the need to do so.”

According to the National Weather Service, heat alerts have been issued from Minneapolis to New Orleans and include 22 states and about 100 million people, from the Midwest to the Gulf of Mexico and into the Great Plains. High temperatures are expected to reach the upper 90s to the low 100s through at least Thursday.

“When factoring in brutal humidity levels, maximum heat indices could approach 120 degrees,” according to the federal agency. “While it is not uncommon for August to feature dangerous heat, these temperatures are extremely anomalous and likely to break numerous daily and potentially monthly records.”