MISO, SPP issue weather-related advisories as Central US braces for higher temperatures

The Midcontinent Independent System Operator issued a hot weather alert and conservative operations notice covering its footprint for July 21-25, and neighboring Southwest Power Pool issued weather and resource advisories for its region in the same period as temperatures and power demand are set to rise across the Central US.

MISO's advisories are in effect from 8 am ET July 21 to 10 pm July 25. The regional transmission organization, which manages the electric grid across 15 states in the US Midwest and South, is declaring conservative operations because of "forecasted hot weather, increased demand and ongoing forced generation outages that may impact generation performance," according to the July 17 notice.

SPP's weather advisory covers the central and southern regions of its 14-state balancing authority area and is effective from 12 pm CT July 21 to 8 pm July 24, according to a late-afternoon July 16 notice. The resource advisory, issued July 17, is effective for the entire balancing authority from 12 pm July 21 to 9 pm July 22.

MISO's advisories instruct its member operators to review outage plans to determine whether any scheduled or ongoing maintenance or testing on monitoring, control, generation, or transmission equipment can be deferred, revoked or canceled.

For SPP, weather advisories are issued to raise awareness of potential threats to reliability among entities responsible for operating transmission and generation facilities. The resource advisory was declared because of expected high loads and uncertainty over forecasts for variable energy resources, such as wind- and solar-powered generation.

"There is potential that high temperatures could cut out some wind resources, which can occur when temperatures warm above 104 [degrees Fahrenheit]," SPP spokesperson Meghan Sever said in a statement to Platts. "At this point, that possibility is uncertain, but could happen should temperatures rise."

Wholesale power prices

MISO's Indiana Hub on-peak day-ahead power for July 18 delivery dropped about $9.75 from the previous settlement to trade around $54.25/MWh during July 17 trading on the Intercontinental Exchange. The Indiana Hub on-peak day-ahead next-week contract for July 21-25 delivery settled at $114/MWh, down $11/MWh from the previous settlement.

By comparison, Indiana Hub day-ahead on-peak locational marginal prices have averaged $67.46/MWh so far in July, 53.5% higher than the July 2024 average, according to MISO data.

SPP's North Hub on-peak day-ahead power for July 18 delivery rose by about $6.75/MWh over the previous settlement to trade near $46/MWh on ICE. The corresponding SPP South Hub on-peak day-ahead contract climbed roughly $4 to settle near $54/MWh.

By comparison, SPP North Hub on-peak day-ahead LMPs have averaged $45.65/MWh this month, an increase of 14.4% from the July 2024 average, according to SPP data. South Hub day-ahead on-peak LMPs have averaged $46.58/MWh this month, 7.3% above the July 2024 average.

Market conditions

MISO forecast systemwide peakload at 108.4 GW July 21 and 117.7 GW July 22. For comparison, MISO's peakload so far this month has averaged 108.1 GW, 6.3% higher than the July 2024 average.

MISO's all-time peakload is 127 GW, set July 20, 2011.

Population-weighted temperatures across MISO's footprint are forecast to average 80.3 degrees Fahrenheit July 21-25, according to CustomWeather data. MISO has historically seen population-weighted temperatures averaging 76.1 F across its footprint for the same five-day period in July. The population-weighted temperature in MISO so far this month has averaged 78.2 F, according to CustomWeather data.

SPP forecast systemwide peakload to average 53.9 GW for July 21-23. For comparison, SPP's peakload so far this month has averaged 46.7 GW, which is roughly identical to the July 2024 average.

SPP's peakload record for this month is 54.394 GW, set July 15, 2024. Its all-time peakload is 56.184 GW, set Aug. 21, 2023.

Population-weighted temperatures across SPP's footprint are forecast to average 86 F July 21-25, according to CustomWeather data. SPP has historically seen population-weighted temperatures averaging 81.3 F across its footprint for the same five-day period in July. The population-weighted temperature in SPP so far this month has averaged 79.9 F, according to CustomWeather data.