MISO activates emergency measures amid record heat wave

In response to a severe heat wave affecting its operational area, the Midcontinent Independent System Operator (MISO) initiated maximum generation procedures on Thursday, August 24th. MISO stated it was grappling with forced generation outages, abnormally high temperatures, and a higher-than-expected load. The emergency measures began at noon as temperatures soared to 95°F and above across most of the MISO system. By Thursday night, the grid operator had lifted its maximum generation warning. A new alert was issued early Friday for lingering heat in MISO South.

During the peak of the heat wave, MISO recorded a demand of 122 GW, falling short of its all-time peak demand record of 127 GW set on July 20, 2011. The hub Locational Marginal Prices (LMPs) reached around $220/MWh in MISO Midwest and $150/MWh in MISO South. MISO had forecasted a peak demand of 127 GW for the day, with cleared offers slightly above 121 GW.

MISO ordered load-modifying resources for over seven hours, avoiding the more drastic measure of load shedding. This was the first time MISO had to deal with a summertime energy emergency, despite having faced similar heat wave conditions in late July.