PJM Issues Geomagnetic Disturbance Warning, Flags Limited Risk to Grid

The PJM Interconnection, a regional transmission organization that coordinates the movement of wholesale electricity in all or parts of 13 states and the District of Columbia, has issued a geomagnetic disturbance warning. This alert, which extends through Sunday, May 12, highlights the potential impacts of solar activity on the grid while emphasizing limited risks to grid operations.

Geomagnetic disturbances, caused by activity on the sun's surface, can induce powerful electric currents that may travel through high-voltage transmission facilities. These currents can flow through grounded grid equipment, potentially disrupting or damaging transmission facilities. In the past, such disturbances have led to power outages and transformer damage, as seen in the 1989 Quebec blackout and the Salem Nuclear Power Plant transformer damage in New Jersey.

PJM's warning aligns with alerts issued by the National Oceanic and Atmospheric Administration (NOAA) Space Weather Prediction Center. NOAA monitors solar activity and the Earth's magnetic field, issuing alerts and warnings to grid operators to prepare for potential impacts. In response to NOAA alerts rated above a certain threshold, PJM issues warnings to generation and transmission operators to prepare for possible impacts of space weather.


PJM's members play a crucial role in detecting and measuring ground-induced currents during geomagnetic disturbances. Special equipment has been installed to monitor these currents at various locations. When a geomagnetic disturbance is forecast, PJM monitors these detectors closely. If sustained ground currents at a certain level are detected, PJM's Emergency Procedures notice guides its members in responding to solar activity alerts and warnings.

PJM is taking specific actions to mitigate potential impacts on the grid during the extended warning period. These actions include:

1. Monitoring GMD activity closely and coordinating with generation and transmission owners.
2. Implementing winter readiness measures, such as improved generator operational and seasonal reporting requirements, adjusted short-term forecasting, and enhanced communication protocols with generation owners.
3. Requesting and receiving FERC approval to change market rules, allowing generators to update their Day-Ahead Market operating parameters in real time, providing PJM operators with greater situational awareness of generators' capabilities at all times.


The extended warning affects PJM's coordination with neighboring grid operators and generation owners. PJM is in close coordination with these stakeholders to ensure preparedness and minimize potential impacts. By working together, PJM and its partners can better navigate the challenges posed by geomagnetic disturbances and maintain grid reliability.

Lessons from past geomagnetic disturbances, such as the 1989 Quebec blackout, highlight the importance of preparedness, communication, and collaboration among grid operators, generation owners, and neighboring grid operators. By learning from these experiences, PJM can refine its grid reliability strategy and better protect against future disturbances.

In conclusion, PJM's geomagnetic disturbance warning underscores the potential impacts of solar activity on the grid while emphasizing limited risks to grid operations. By issuing warnings, monitoring GMD activity, and coordinating with stakeholders, PJM is taking proactive measures to ensure grid reliability and minimize potential impacts. As the energy transition continues, understanding and addressing the long-term effects of geomagnetic disturbances will be crucial for maintaining a robust and resilient grid.