By Amanda Durish Cook

CARMEL, Ind. — MISO expects to call on load-modifying resources (LMRs) this summer despite its own estimates that it will have about 149 GW of total projected capacity on hand to cover a predicted 125-GW seasonal peak.

During an annual summer readiness workshop April 23, Resource Adequacy Coordination Engineer Eric Rodriguez said MISO says there is a 70% probability that it will have to declare an emergency in order to access 12 GW of LMRs in summer. The RTO will face challenges if it experiences a large number of resource outages coupled with high load.

Using data from the National Oceanic and Atmospheric Administration, MISO is expecting above-normal temperatures for its South region and the eastern portion of the footprint. Rodriguez said the summertime projections are “fairly typical.” The RTO expects July and August to contain the most risk.

The 125-GW peak demand forecast is nearly identical to the prior two planning years. MISO requires a 146-GW reserve margin requirement this planning year, which it expects to exceed by nearly 3 GW — both in line with last summer’s forecasts. Last year, summer load peaked at 121.6 GW on June 29, while load averaged at 86.6 GW over the season. MISO’s all-time, 127-GW summer peak occurred on July 20, 2011.

CEO John Bear said the adequate supply projection doesn’t mean MISO is “off the hook” with respect to challenging summer circumstances. However, the RTO was able to effectively manage recent emergency events in September and January because of its focus on preparation, he said.

Additionally, MISO’s coordinated seasonal assessment found nothing out of the ordinary for the upcoming summer. The assessment simulates unlikely system contingencies to detect potential voltage and thermal issues on the system. Engineer Benny Relucio said the RTO unearthed nothing for which it doesn’t already have mitigation measures in place.

MISO’s planning also assumes a near- or slightly below-average hurricane season, producing only two to three storms considered Category 3 or higher. The RTO expects the ongoing El Nino to produce more wind shear and cooler-than-average water temperatures in the Atlantic Basin, limiting hurricane activity.

“This means good news for MISO, bad news for hurricanes,” said Michael Carrion, of the RTO’s real-time operations team.

MISO will continue to conduct weekly summer readiness drills and periodic hurricane preparedness drills with market participants through late May.