Image courtesy 123rf
An expected heat wave has punished much of the eastern and midwestern US this week, prompting emergency measures from the nation’s two largest regional grid operators.
PJM Interconnection, which serves 13 states and Washington, D.C., issued a Maximum Generation Alert and Load Management Alert for June 24—the second consecutive day under heightened readiness. After midday on June 24, PJM extended the alerts to June 25.
Maximum Generation Alerts are directed at transmission and generation owners, urging them to defer maintenance or testing that could take generation units offline. Load Management Alerts, meanwhile, serve as notice that demand response programs may be activated.
On June 22, PJM reported a preliminary peak load of over 143,000MW. That figure jumped to over 161,000 MW on June 23. As of June 23, the following levels were forecast through Thursday:
- 160,000 MW on June 24
- 155,000 MW on June 25
- 148,500 MW on June 26
PJM also issued a NERC EEA Level 1, or EEA-1. This is defined as when a grid operator foresees or is experiencing conditions where all available resources are committed and that reserve margins are under pressure.
Additionally, PJM extended its Hot Weather Alert to June 26, a standard protocol used to ready transmission and generation owners for forecasted temperatures above 90°F and high humidity.
As of 1pm EST on June 24, natural gas was providing 45.5% of generating capacity in PJM territory. Nuclear and coal followed with 20.8% and 19.6%, respectively. Solar represented 7%.
To the west, the Midcontinent Independent System Operator (MISO) is facing its own set of reliability challenges as heat blankets much of its territory. On June 23, MISO declared a Maximum Generation Event, which it terminated later that evening. However, a Max Gen Warning remains in effect through 9pm EST on June 24.
This warning indicates that grid conditions are tightening and may soon require emergency measures.
Generators across MISO are being asked to maximize output when possible and report any constraints, such as fuel supply issues or environmentally limited resources.
A Max Gen Event Step 1b—the first true emergency step—was declared on June 23, signaling that supply margins were critically thin. Under such conditions, MISO may begin curtailing nonessential electricity exports, activating demand response programs, or dispatching emergency generation.
On June 24, MISO reiterated on social media that it is “closely monitoring grid performance and coordinating with our members to ensure reliable operations.”
Originally published by Kevin Clarke in Factor This Power Engineering.
