The PJM Interconnection has taken a number of actions over the past several days to maintain reliable operations as extreme heat pushed electricity demand to near record levels.
On July 2, PJM’s peak instantaneous load was approximately 162,700 MW between 5 and 6 p.m., according to preliminary figures, but that figure was suppressed by the use of demand response programs.
The peak load is likely to have surpassed the all-time PJM record of 165,600 MW set in 2006, PJM said on July 3.
PJM won’t have an official preliminary peak figure until after the 60-day period required to calculate the performance of approximately 6,000 MW in demand response resources that were activated.
During the July 2 evening peak, PJM executed a series of procedures to manage demand and maximize supply when some generation tripped offline, including calling on emergency demand response.
PJM also issued a warning to prepare some transmission owners and utilities for the possibility of curtailing data centers and other large loads in their regions and moving them to backup generation. Ultimately, that action was not required and service was not impacted.
"During any extreme weather event, there is always the possibility that challenges will arise on the system. PJM coordinates with its generation and transmission owners as we respond to the needs of the grid in real-time based on actual conditions to preserve reliability for the 67 million people we serve," it said.
The Maximum Generation Alert and Load Management Alert was in effect for July 3 for the PJM footprint. The alert does not require any action from customers. This 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 within the PJM region. This alert is also used to notify neighboring systems that electricity exports from PJM may be curtailed, serving as a procedural step that allows those neighboring regions to plan accordingly.
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 Pre-Emergency and Emergency Demand Response. Demand Response programs pay customers in advance who sign up to allow reduction of their electricity use in emergencies.
PJM activated its Pre-Emergency Demand Response and Emergency Demand Response customers across PJM the afternoon of July 3 to increase reserves on the system for the evening peak.
A Hot Weather Alert remained in effect for the entire region PJM serves through July 4 and was extended through July 5 for only the Mid-Atlantic and Dominion transmission zones.
A Hot Weather Alert is an established procedure PJM issues ahead of forecasted hot weather and/or high humidity to prepare transmission and generation personnel and facilities for expected increases in electricity demand, or load.
PJM has also taken the following actions to prepare for the extreme heat and humidity:
• PJM issued a Maintenance Outage Recall on June 25 ahead of the week’s forecasted hot weather. The recall requested for all maintenance outages to be returned to service by July 3 to increase the amount of generation available to meet customer demand.
• PJM requested and received approval of an emergency 202c order by the U.S. Department of Energy to direct transmission owners, if required as a last resort prior to voltage reduction or load shed, to curtail data centers and other large loads that have backup generation. PJM has requested that this order be extended through July 6.
• PJM also submitted and received approval of a DOE 202c emergency order for temporary relief from environmental permit restrictions for generating units, effective July 1 through July 3. This order was extended through July 6.
