PJM continued to operate reliably through the unseasonably hot weather Tuesday, calling on demand response customers to help blunt peak demand in the late afternoon and evening.
As was the case on Monday, on Tuesday, May 19, PJM activated Pre-Emergency Demand Response customers in the BGE, PEPCO and Dominion service areas to address localized transmission constraints. Also on Tuesday, PJM called on Pre-Emergency Demand Response customers of AEP Ohio in the Columbus area to address transmission constraints in the area.
Demand response or load management customers are paid to reduce their electricity consumption to ease load during critical periods.
DOE Issues Order for Expedited Process for Running Backup Generation
The U.S. Department of Energy issued an order on Monday evening, under section 202(c) of the Federal Power Act, authorizing PJM in collaboration with its Transmission Owners and Electric Distribution Companies to direct the operation of customer-owned backup generation facilities at data centers or other large load facilities, if needed, to help avoid service interruptions for residential customers during the unseasonable hot weather stretch. The order is effective through May 20.
PJM requested and was granted a similar order this January during Winter Storm Fern due to the extreme cold temperatures. PJM was able to operate reliability through the severe winter weather without calling on these resources.
While PJM does not expect to have to transfer data centers to back-up generation at this time, the DOE order offers one more tool to minimize the risk of residential customers and other customers without backup generation from experiencing outages.
Outlook for May 20
PJM has issued a Maximum Generation Alert and Load Management Alert for BGE, PEPCO, and Dominion service areas for May 20, as forecasted temperatures remain in the 90s for the eastern portion of the MidAtlantic and Dominion service areas. The same alert was in effect May 18-19 for the entire PJM footprint, though temperatures and electricity demand are expected to drop through much of the PJM region on Wednesday.
PJM forecasts energy demand, or load, to peak at about 116,600 on May 20, after serving hourly peaks of about 133,000 on May 19 and above 136,000 MW on May 20.
While PJM is prepared to serve loads in excess of 150,000 during this year’s summer peak, system conditions have been tight this week due to over 40,000 MW in generation outages in addition to transmission outages. Spring and fall months are used by generation and transmission owners for required maintenance because weather is typically mild and the corresponding electricity use is lower.
The Maximum Generation Alert is targeted at transmission/generation owners, who then determine if any maintenance or testing on equipment can be deferred or canceled. By deferring maintenance, the units stay online and continue to produce energy that is needed to serve electricity demand, or load, within the PJM region.
PJM issues this alert at the same time as a Load Management Alert, which gives advance notification that load management action may be declared, including non-emergency and emergency Demand Response.
Hot Weather Alerts
A Hot Weather Alert is in effect for all of the PJM region on May 19 except for ComEd, and a similar alert has been issued for May 20 in the Mid-Atlantic and Southern zones.
A Hot Weather Alert is a routine procedure PJM issues ahead of forecasted hot weather and/or high humidity to prepare transmission and generation personnel and facilities for expected increases in load. This procedure does not require any action from customers.
Forecast Peaks
As of May 19 at 3:20 p.m., PJM was expecting to serve the following approximate peak loads on May 19–20:
| Date | Forecast Peak Load |
| May 19 | 135,728 MW |
| May 20 | 116,557MW |
These numbers are subject to change and will be updated periodically.
A dedicated team of operators uses sophisticated technology to balance supply and demand and direct the power grid 24/7 from PJM’s control rooms. They prepare multiple potential scenarios that could be impacted by weather, emergency conditions or equipment failure. They adjust resource output with changes in demand and ensure that no transmission lines or facilities are overloaded. The team also watches for unusual conditions and reacts to them to protect the electricity supply.