PJM Interconnection maintained reliable grid operations during an unprecedented July heat wave that pushed electricity demand to a record high and required the use of all available generation resources, it said in a Friday statement.
PJM, a regional power grid operator that coordinates electricity supply and transmission across 13 US states and the District of Columbia in the mid-Atlantic and parts of the Midwest, reached a preliminary all-time peak load of 168,158 megawatts between 5 and 6 pm on July 2, surpassing the previous record of 165,563 MW set Aug. 2, 2006. The estimate includes demand response resources that reduced electricity consumption during the system emergency.
The record occurred as the PJM region experienced its hottest-ever average temperature, reaching 97 degrees on July 2. Temperatures in parts of the Mid-Atlantic climbed into the low 100s. At the same time, forced generation outages ranged from 18,100 MW to 19,400 MW between July 2-4, well above the 12,800 MW average outage level recorded during the top 10 summer peak days of the past three years.
"This was the highest peak we have ever served, through an unprecedented heat wave," said PJM Dispatch Senior Manager Paul Dajewski. He credited coordination among PJM, generators, transmission owners and neighboring grid operators for maintaining system reliability.
As demand approached its peak July 2, several generators tripped offline, prompting PJM to activate emergency procedures, including calling on demand response resources. PJM estimated demand response performance at 6,113 MW on July 2 and 5,037 MW on July 3.
The preliminary peak load reflects the electricity demand PJM would have served without curtailment actions, it said. Final demand response performance and official peak load figures will be released after a 60-day evaluation.
The peak approached PJM's summer forecast of 169,128 MW, a level expected to occur only once in 10 years. Dajewski warned that while the system performed successfully, capacity margins remain a concern as demand growth continues to outpace new supply additions.
PJM also said it received the US Department of Energy's approval for emergency orders allowing temporary relief from environmental operating limits and potential curtailment of certain large loads if needed. PJM estimated about 3.25 GW of generation operated beyond normal permit limits. The emergency orders were effective July 1-6.