Monday, August 11, 2014
Dodging Solar Bullets
Massive blackouts—pipeline explosions—whole regions of Europe or North America plunged into the nineteenth century, but without even the rudiments of that century's technology. Elevators that don't elevate, ventilators that don't ventilate, gas pumps that don't pump, hospitals that turn into charnel houses. Entire cities evacuated and their populations dying on their frantic attempts to escape to nowhere.
No, this isn't a movie review of the latest mega-disaster flick. It is a fairly realistic scenario of what could have happened on July 23, 2012, if a certain cluster of sunspots had been facing directly toward the earth, rather than pointing out away from us toward a space probe called STEREO A. As it happened, STEREO A had a front-row seat at a performance that engineers hope we will never witness here—but one that could happen any time.
What happened that day was not just one, but two coronal mass ejections (CMEs). Often associated with, but distinct from, the brilliant solar flares that arc above the sun's surface every now and then, coronal mass ejections contain the energy of millions of nuclear bombs and send tons of charged particles flying out into space. Entangled with the particles are spaghetti-plates full of tangled magnetic field lines, and the magnetic fields are what can damage our electrical and mechanical infrastructure.
When a CME encounters the earth's magnetic field, the normally fairly stable domestic field jumps around like the proverbial cat on a hot tin roof. And as every electrical engineer knows, changing magnetic fields near conductors induce voltages and currents in those conductors. Substitute "power lines" and "pipelines" for "conductors" and you begin to see the problem.
While these structures are protected against the normal kinds of mishaps that can befall them—lightning in the case of power lines, breaks in the case of pipelines—relatively few such installations are also protected against the unique sort of stresses that a record-breaking geomagnetic storm can induce. And geomagnetic storms, along with brilliant auroras near the polar regions, are what happens when a large CME hits the earth.
The last major geomagnetic storm that did considerable damage occurred in 2003, knocking out a series of electric-grid transformers in Sweden. Utility operators usually have on hand one or two spare transmission transformers—the big boxes in substations that cost upwards of millions of dollars each—but not a dozen. And even if they did, hauling those multi-ton pieces of gear around the country to replace ones burned out by a geomagnetic storm is not the light task of a few hours' time. Multiply this actual event by a factor of two or ten or twenty, and you can see how bad things could get.
What can be done from an engineering point of view to protect infrastructure assets from a large geomagnetic storm? We will concentrate on the protection of the electric grid, since its loss would be by far more immediately consequential than the loss of pipelines.
If grid operators are given enough warning, they can call for a pre-emptive voluntary blackout that disconnects vulnerable transformers from the long lines that will pick up the high currents and voltages that would otherwise cause damage. The problem with this is, nobody wants to be the one to decide to pull the switch, especially if the storm turns out to be less severe than expected. Another problem is that there is currently no good way to predict the exact effects of a given geomagnetic storm on a particular part of the grid. So the safe thing to do would be to shut down the whole system for the duration of the storm, which usually lasts only a few hours. But a region-wide blackout lasting several hours is a serious disruption of its own, and few grid operators are currently willing to do such a thing based on only the fuzzy and general forecasts of geomagnetic storms that are presently available.
Another alternative is to install special protective gear designed to bypass the large energy generated in power grids by geomagnetic storms. This would allow the grid to keep working right through the storm, but has the disadvantage of costing millions of dollars and not doing a blessed thing until the storm hits. This reminds me of those vending machines you used to see at airports where you could buy $50,000 of life insurance for something like a quarter, valid only during your upcoming flight. I suppose somebody may have collected on one of those policies, but I doubt it. Still, this would be the safest course, all things considered.
Healthy societies have institutions that look ahead to unlikely eventualities, so that when they happen, as sooner or later they surely will, the society rolls through the crisis while maybe sustaining some damage, but otherwise stays intact. The closest we have come in the U. S. to a crisis like the one a geomagnetic storm might cause was Hurricane Katrina, the one that devastated New Orleans in 2005. Sad to say, New Orleans was grossly unprepared for Katrina. Its infrastructure of dikes and canals had been neglected for decades, despite warnings that if something like Katrina hit, large parts of the city would be underwater, and they were. Over 1,800 people died in a disaster that was, fortunately, of limited geographic extent. Multiply Katrina by ten or twenty times the area, and you can begin to see what a perfect geomagnetic storm might do.
In a recent issue of National Review, Christopher DeMuth points out that past generations of U. S. citizens allowed the federal government to go into debt, but always for a reason that was forward-looking: to win a war, for example, or to finance infrastructure improvements such as canals, railroads, and interstate highways. By contrast, today we are continually warned of our crumbling infrastructure, but the massive debt we are incurring is going mainly for payments to persons—consumption, in other words, not investment for the future.
The amount of money it would take to improve geomagnetic-storm forecasting and power-grid protection to the point that we could cross a geomagnetic-storm disaster off our list of things to worry about, is not large. Whether public or private funds, or a combination, should pay for it is not the question. The question is whether society still has enough foresight to avoid needless disasters—or whether we have to experience them first before we do anything about them.
Sources: A good brief description of the nearly-disastrous CME event of July 23, 2012 was carried online by IEEE Spectrum at http://spectrum.ieee.org/tech-talk/aerospace/astrophysics/earth-dodged-solar-magnetic-storm-bullet-in-2012. The technical paper on which the report was based is Liu, Y. D. et al. "Observations of an extreme storm in interplanetary space caused by successive coronal mass ejections." Nature Communications 5:3481 (doi: 10.1038/ncomms4481) (2014). The problem has not gone entirely unnoticed by government officials, as the threat evaluation report on geomagnetic storms at the U. S. Department of Homeland Security found at https://www.dhs.gov/xlibrary/assets/rma-geomagnetic-storms.pdf shows. I also referred to Wikipedia articles on coronal mass ejections, solar rotation, and Hurricane Katrina. Christopher DeMuth's article "Our Democratic Debt" appeared on pp. 28-34 of the July 21, 2014 issue of National Review.