The U.S. Department of Energy issued an emergency order on October 12 to help PJM maintain grid reliability during elevated demand and planned equipment outages. Effective October 13–16, the order allows PJM to direct large loads, including data centers, to use backup generation if necessary.
In its operations update, PJM said it had extended its Maximum Generation Alert and Load Management Alert through October 14. PJM also noted that the alerts did not require customer action at the time and that it had not called on large-load backup generation.
For data center operators, the event is a reminder to check how the UPS, batteries and generator work together. During a utility outage, the UPS battery supports the load while the generator starts and reaches stable voltage and frequency. The UPS must then accept generator power without disrupting the protected equipment.
Battery runtime should cover generator start-up, stabilization and transfer, with a margin for delayed starts or failed attempts. Operators should test this sequence under realistic load rather than relying only on the generator’s nominal start time.
Facilities using a low frequency online UPS should also verify its generator input requirements. Generator sizing must account for the protected load and the UPS charging demand after the transfer. A coordinated site test is the clearest way to confirm that the complete backup power system performs as intended.
