Space Weather: Geomagnetic Storms Could Wreak Havoc on the North American Power Grid

In a year that has been dominated by climate-change-related natural disasters—a bizarre winter storm in February that caused extended power outages in Texas, extreme drought and record wildfires in the West, extraordinary heat waves that broke all-time temperature records by over 10°F in parts of the Pacific Northwest and western Canada, and massive flooding from hurricanes on the Atlantic and Gulf Coasts—there’s another concern, not at all related to climate change, that you may not be aware of: space weather.

Introducing space weather and geomagnetic storms

Geomagnetic storms (an intense form of space weather caused by coronal-mass ejections from the Sun—the source of northern lights) remain a little-recognized, but significant threat to our power grid. A 2008 National Research Council report estimated that a geomagnetic storm as strong as one experienced in 1859, if it occurred today, could destroy thousands of transformers throughout the northern half of North America and cause power outages lasting months or even years. (The long recovery period due to the time required to manufacture replacement utility-scale transformers, which are custom-made with a typical lead time of 12 to 24 months.)

That 1859 geomagnetic storm, referred to as the Carrington Event, occurred before the power grid existed, but it was intense enough to cause some telegraph wires and equipment to catch on fire, and it resulted in northern lights (aurora borealis) being seen as far south as Cuba. The northern lights were bright enough in the Colorado Rockies, according to one report, that you could read a newspaper at midnight.

In March 1989, a geomagnetic storm, less intense than the 1859 event, resulted in damage to the power grid in Quebec, knocking out power for six million utility customers in an outage that lasted up to nine hours.

*NOAA GEOS-17 Satellite, with functionality for monitoring space weather that become operational in August 2021. Image: NOAA Space Weather Prediction Center*

Reporting and predicting geomagnetic storms

Space weather events are tracked and reported by the NOAA Space Weather Prediction Center in Boulder, Colorado The most concerning events are geomagnetic storms, but impacts also include high-elevation solar radiation and radio interference. Potential impacts on the power grid are described here.

Because geomagnetic storms have their origins with coronal-mass ejections from the sun (solar flares), such events can be predicted from observations of the sun and measurements of magnetic fields resulting from those ejections. Usually, there is a two- to four-day warning of geomagnetic storms, providing an opportunity for utility companies to implement protective measures. NOAA has been putting in place satellites that provide that advance warning; the most recent of those is the GEOS-17, which became operational for tracking space weather in August 2021.

The Space Weather Prediction Center has developed various scales to report the severity of different types of space weather. Their scale for geomagnetic storms is shown in the figure below, with color-coding to show Minor (G1) through Extreme (G5) events. NOAA has similar scales for Solar Radiation Storms (which can cause radiation risks for astronauts and occupants of high-elevation planes), and Radio Blackouts (which can interfere with radio signals and interrupt navigation systems).

Alert levels for geomagnetic storms

*NOAA Space Weather Scale for geomagnetic storms. Source: NOAA Space Weather Prediction Center*

The NOAA Space Weather Prediction Center provides daily forecasts of various space weather phenomena, including geomagnetic storms. Those interested can also sign up to receive notifications and alerts about space weather.

How geomagnetic storms can affect the power grid

This gets complicated! As explained by the U.S. Geological Survey (USGS) Geomagnetism Program, potential impacts to the electricity grid from geomagnetic storms result from the interaction between these external magnetic fields and geoelectric fields in the earth. Terrestrial geoelectric fields are always present, because the earth’s crust, mantle, and oceans are electrically conducting. These geoelectric fields constantly fluctuate due to the magnetic fields surrounding the earth.

Problems can occur when intense geomagnetic storms occur due to coronal-mass ejections from the sun. During the most intense geomagnetic storms, geoelectric fields can be induced that are strong enough to interfere with electric grids—even causing blackouts and damaging transformers.

The above-mentioned NRC report explains that the damage occurs because our power grid is designed to handle alternating current (AC), but not the direct current that can be induced by such events. This results in excessive heat and, in extreme cases, melting of transformer cores in utility substations.

While geomagnetic storms (as evidenced by northern lights) are most evident at higher latitudes, the potential impact on power grids is more complex and influenced by the underlying geology. This information is collected by 24 ground-based geomagnetic observatories in North America maintained by USGS Geomagnetism Program, which works closely with the NOAA Space Weather Prediction Center.

This USGS program published maps in early-2020 showing the likely impact of a severe (100-year) geomagnetic storm on U.S. power distribution lines in the northern two-thirds of the U.S., where magnetic surveys have been carried out. The regions of the U.S. at greatest risk of potentially damaging voltage perturbations are the Eastern Seaboard, where our highest population densities are found, and the Upper Midwest.

Susceptibility of U.S. power distribution lines to severe geomagnetic storms in the northern two-thirds of the country from a once-in-a-century geomagnetic storm. Induced voltage from such storms is shown with color-coding, ranging from 10 volts in deep violet to 900 volts in yellow. Source: USGS Geomagnetism Program

What is being done about our vulnerability to space weather?

The 2008 NRC report and the 1989 damage to the electric grid in Quebec served as wake-up calls for utility companies to make changes necessary to minimize this risk, and our power grid is a lot more resilient today as a result. When intense space weather is predicted, utility companies can institute protective measures to isolate their transformers from geoelectric current and voltage fluctuations. While such actions may cause temporary blackouts, they should protect equipment from significant damage and allow full power to be restored quickly following the space weather event.

For homeowners and business owners, being aware of space weather and power outages that could result from such events can help them prepare. Most of the preparation recommended by the NOAA National Weather Service involves the sort of preparation one would do in advance of any storm that might knock out grid power: filling containers of water; making ice in your freezer; making sure you have a supply of food on hand; making sure you have at least a half-tank of fuel in your car; keeping a flashlight and extra batteries handy; preparing for your garage-door opener to not work (knowing how to manually open the door and keeping a house key with you if you normally enter through the garage); etc.

There are also some protective measures we can take in our homes and businesses—just as many of us take precautions during thunderstorms. An article in Today’s Homeowner, posted in 2011, in advance of a cyclical period of predicted geomagnetic activity, recommended installing a whole-house surge protector, putting delicate electronic equipment on individual surge protectors, and unplugging electronic equipment in advance of particularly strong geomagnetic storms.

For those especially concerned, the article continued, one could place small electronic equipment, such as cell phones, in a homemade Faraday cage. Such a Faraday cage could be made, the article suggests, from a metal trash can with lid (placing electronic gear in the trashcan within a cardboard box so as not to be in direct contact with the metal). The extensive comments posted with the article range from extreme “prepper” advice to humorous, dismissive quips about wearing tinfoil hats.

Preparing for potential longer-term power outages caused by geomagnetic storms points to the need for resilience at the building scale. We should provide passive survivability in our buildings and, if deemed necessary, make sure that backup power systems are available to be able to get by during a period of extended power outage following such an event.

Unlike with climate change, there is nothing we can due to lessen the likelihood of geomagnetic storms. (Those of us involved with resilience should do everything we can to mitigate climate change through carbon-emission reductions and carbon sequestration.) But we can do a lot to improve our resilience to the blackouts that could be caused by geomagnetic storms.

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Along with founding the Resilient Design Institute in 2012, Alex is founder of BuildingGreen, Inc. To keep up with his latest articles and musings, you can sign up for his Twitter feed. To receive e-mail notices of new blogs, sign up at the top of the page.

David W. Orr, Ph.D

David W. Orr is Paul Sears Distinguished Professor of Environmental Studies & Politics, Emeritus. He also served as “Counselor to the President” of Oberlin College for ten years. He is the author of eight books, including Dangerous Years: Climate Change and the Long Emergency (Yale, 2016) and Down to the Wire: Confronting Climate Collapse (Oxford, 2009) and co-editor of three others. He has authored over 220 articles, reviews, book chapters, and professional publications. In the past twenty-five years he has served as a board member or adviser to ten foundations and on the Boards of many organizations including the Rocky Mountain Institute, Bioneers, and the Aldo Leopold Foundation.

He is currently a Trustee of the Alliance for Sustainable Colorado, Children and Nature Network, and the WorldWatch Institute. He has been awarded nine honorary degrees and a dozen other awards including a Lyndhurst Prize, a National Achievement Award from the National Wildlife Federation, leadership awards from the U.S. Green Building Council (2014) and from Second Nature (2012), and a lifetime achievement award from Green Energy Ohio and the North American Association for Environmental Education. He has lectured at hundreds of colleges and universities throughout the U.S., Europe, Latin America, and Asia. He headed the effort to design, fund, and build the Adam Joseph Lewis Center, which was named by an AIA panel in 2010 as “the most important green building of the past thirty years,” as “one of thirty milestone buildings of the twentieth century” by the U.S. Department of Energy, and as one of “52 game-changing buildings of the past 170 years” by the editors of Building Design +Construction in January, 2016. He was instrumental in the design and funding of the Peter B. Lewis Gateway Center. He is the founder of the Oberlin Project and a founder of the journal Solutions. His current work is on the state of American democracy.