PJM issued a maximum generation alert and a load management alert for Sept. 1, telling generator owners across its territory to defer or cancel maintenance so units stay on line through several days of high heat and humidity. The grid operator's own forecast, current as of 5 p.m. on Aug. 31, puts the peak at 156,083 megawatts on Sept. 3, the top of a three-day climb that starts at 150,913 MW on Sept. 1 and rises to 155,966 MW on Sept. 2.
The alerts do not ask anything of customers. They are aimed at the operators who own the equipment that keeps power flowing.
What the alerts cover
A maximum generation alert goes to transmission and generation owners, who then decide whether planned maintenance or equipment testing can wait. Keeping that equipment in service means more units stay available to meet demand inside PJM's footprint. The alert also tells neighboring grid operators that electricity exports out of PJM could be curtailed, giving those systems time to plan around a smaller supply from PJM.
PJM issued the load management alert at the same time. It gives advance notice that the operator may call for load management steps, including Pre-Emergency and Emergency Demand Response. Demand response programs pay customers who sign up ahead of time to cut their electricity use during emergencies.
Hot weather alert runs through Sept. 3
Separately, a hot weather alert covers PJM's entire region through Sept. 3. PJM issues this type of alert ahead of forecast heat or high humidity so transmission and generation staff and equipment are ready for the demand increase that comes with it.
| Date | Forecasted peak load |
|---|---|
| Sept. 1 | 150,913 MW |
| Sept. 2 | 155,966 MW |
| Sept. 3 | 156,083 MW |
How PJM runs the grid through the alert period
A team of operators works PJM's control rooms around the clock, using technology to balance supply and demand on the power grid. They build out scenarios for how weather, emergency conditions or equipment failure could change the picture, then adjust generator output as demand shifts and check that no transmission line or facility is carrying more than it should. The same team watches for anything unusual on the system and responds to protect the supply of electricity.
Together, the three alerts describe a standard PJM response to a hot stretch rather than a declared emergency. The maximum generation alert works on the supply side by keeping generators available. The load management alert works on the demand side by putting Pre-Emergency and Emergency Demand Response on standby. Neither step requires PJM to call on demand response or curtail exports; it puts the tools in place in case the peak loads PJM is forecasting arrive as expected.
