How a Geomagnetic Disturbance (GMD) Could Devastate the Grid
Image courtesy of Peter D. Tillman under Attribution 2.0 Generic License, resized to 700 x 391 pixels.
I’ve previously written about the potential impact of an electromagnetic pulse (EMP) on the power grid, but that is small peanuts compared to what a geomagnetic disturbance (GMD) could do. GMDs create explosive outbursts from the sun (called a coronal mass ejection or CME) that can travel at extreme speeds and can reach Earth in as little as 15 hours. Because this phenomenon carries the potential for mass destruction, I thought it would be an interesting topic for today’s post.
Why a GMD Might be More Devastating than an EMP
An EMP is an extreme wave or pulse of electromagnetic energy caused by a high-energy explosion (i.e., detonating a nuclear warhead). Obviously, this can wreak havoc on the grid, and making matters worse is that it could theoretically be used as a tool for terrorism.
A GMD is essentially a large eruption in the sun’s upper atmosphere (i.e., the sun’s corona) that creates a CME, which is a massive ejection of billions of tons of plasma and other coronal material that can carry a magnetic field. These radiation storms would cause widespread outages if they directly hit Earth, and could even theoretically result in the extermination of a large percentage of the Earth’s population.
Unfortunately, experts agree that the U.S. power grid is not well-protected from an event like an EMP or a GMD-triggered CME. While a massive CME is rare, scientists believe that Earth will get hit with one sooner or later – frequency is estimated to be once every 100-200 years. And when the next one hits, it would not be the first time.
The most devastating CME ever recorded is the so-called Carrington event that occurred in 1859, which wreaked havoc on the national telegraph system, ignited fires and delivered electrical shocks to telegraph operators. A smaller one hit in 1989, which tripped Hydro-Québec’s La Grande high-voltage transmission network and knocked out power up and down the U.S. East Coast.
Unfortunately, there is not much that can be done from an emergency preparedness perspective to mitigate this risk. While the article linked to above suggests things like developing a strategic reserve of key electrical components and hardening a small percentage of the U.S. grid to serve as a proverbial lifeline if the rest of the country goes dark, but these are obviously national decisions, not utility decisions. In the meantime, let’s just hope we don’t see the next massive EMP or GMD in our lifetimes!
