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Image courtesy of NOAA
Nuclear reactions of the sun create light and heat and, from time to time, the sun ejects a mass of charged particles racing through space called a Coronal Mass Ejection (also known as a solar flare). When that mass reaches the earth, it reacts with the earth’s magnetic field, sending charged particles swirling around the planet. Some of the results are spectacular, including the Northern Lights.
Other results are less desirable. These events are known as geomagnetic disturbances (GMD). Large and high-intensity GMD events are rare. Near the earth’s surface, the movement of particles creates a varying magnetic field. When a varying magnetic field encounters an electrical conductor, it induces a current. When the wires of the electricity transmission system encounter a geomagnetic disturbance, they form a huge electric generator spanning the continent creating what is called a geomagnetically-induced current.
You might think that this is free electricity. It is, but the problem with the induced currents is that they distort the alternating current flowing through the electricity system. These distortions can cause heating and damage in transformers, and if they are of sufficient magnitude and scale, can cause a blackout by disrupting the voltage in the system. This is exactly what happened in 1989 in Quebec, when a geomagnetic disturbance led to a blackout.
To advance the scientific understanding of geomagnetic disturbance events so we can better characterize their potential impact and risk to the U.S. electricity system, the Office of Electricity Delivery and Energy Reliability (OE) asked Los Alamos National Laboratory (LANL) to examine geomagnetic disturbances and their potential effects on the electricity system. The LANL researchers focused on both the characteristics of the disturbance itself, including the magnitude and how the disturbance changes with latitude, and the contributions of the underlying structure of rock below the earth's surface to the effect of the disturbance.
The team at Los Alamos has now completed and published its study which we are posting today on our website. The report offers a scientifically rigorous estimation of a “1 in 100-year geomagnetic event” and advances work previously conducted by the Federal Energy Regulatory Commission (FERC), the North American Electric Reliability Corporation (NERC), and the Electric Power Research Institute (EPRI). Because geomagnetic disturbances could affect the operations and reliability of the electricity transmission system, FERC and NERC are in the process of developing and approving a Reliability Standard to address the issue. We hope that this work contributes positively and can help inform that process.
This research underscores our commitment to protecting the nation’s energy critical infrastructure from all hazards, including GMD events. It is the latest example of our ongoing work with industry and public partners to address risks to the electricity system, including our partnership with NERC in 2009, our study on the manufacturing capacity of U.S. transformer producers, and our support of EPRI’s Sunburst program, a geomagnetically-induced current monitoring system. Moving forward, LANL’s research will help inform our future work on strategies to mitigate risks from GMDs.