A “ferocious” coronal mass ejection that narrowly missed Earth in July 2012 would have caused massive power blackouts, disabled everything that uses electricity, knocked out municipal water supplies, and cost trillions of dollars, according to Daniel Baker, a professor of planetary and space physics at the University of Colorado, Boulder. The billion-ton cloud of magnetized plasma streaming from that solar eruption passed through Earth’s orbit in about 15 hours—among the fastest-moving solar blasts ever recorded.

A solar storm as epic as the one in 1859 known as the Carrington Event, which caused telegraph lines to spark and created auroral displays as close the equator as Cuba, would today wreak at least $2 trillion in damage—20 times greater than Hurricane Katrina in 2005, Baker said. The 2012 solar storm was two to three times as massive as the 1859 event, he said, and had it occurred one week earlier, the world “would still be picking up the pieces.”

The occurrence of another such “superstorm” is not a question of if, but when, he warned.

Baker was one of several witnesses who admonished members of the House Science, Space, and Technology Committee on 10 September about the range of natural and manmade threats to the US electricity grid. Manmade concerns include an electromagnetic pulse (EMP) from a nuclear weapon detonated high in the atmosphere, and terrorist sabotage—whether by cyberattack, through intentional magnetic interference, or with guns or other weapons. The latter threat was brought home in 2013, when unknown attackers carried out an assault on a substation in Metcalf, California, firing more than 100 rounds at transformers and causing $15 million in damage.

Much of the concern over the grid’s physical vulnerability centers on a relatively small number of high-voltage transformers, which weigh hundreds of tons and are typically made to order with lead times of more than one year. A recent Congressional Research Service report noted that high-voltage units constitute less than 3% of all US transformers, but carry 60–70% of the nation’s electricity.

The coronal mass ejection of July 2012 was observed by NASA's Solar Terrestrial Relations Observatory-Ahead (STEREO-A). CREDIT: NASA

“A terrorist organization that wanted to cause massive disruption to the power system could order rifles and armor-piercing bullets on the Internet, place sharpshooters in the back of a station wagon . . . and from a distance put holes in a carefully selected set of critical high-voltage transformers,” said Granger Morgan, an engineering and public policy professor at Carnegie Mellon University. Replacing chain link fences with more opaque and robust enclosures could reduce that risk, he said.

The Department of Energy’s Quadrennial Technology Review, released in April, notes that the US has never experienced the simultaneous failure of multiple large power transformers, an event that would disrupt electricity service over a large area. Although the Edison Electric Institute, the utility industry’s trade group, has established a program for stockpiling spare transformers and parts, the inventory isn’t large enough to meet the recovery needs from a large coordinated attack, the review states. Variations in transformer designs and the challenge of transporting the enormous devices also limit the program’s effectiveness.

A 2012 National Research Council report recommended that DOE and the Department of Homeland Security establish a stockpile of emergency replacement transformers. Somewhat easier to move, and less efficient, the replacements would fill in until permanent replacements could be built. Although DHS conducted a replacement demonstration from 2012–14, implementation has not occurred, Morgan said.

The threat from an EMP attack can be mitigated by hardening new and existing equipment, including shielding control rooms, power supplies, and communication cables, said Richard Lordan, senior technical executive for transmission at the Electric Power Research Institute. Spares of sensitive electronic components, such as relays, Should be kept in shielded locations, and backup electro-mechanical relays, which aren’t vulnerable to EMP, could be installed.

Morgan downplayed the EMP threat, noting that a terrorist organization that managed to acquire a nuclear weapon would be much more likely to detonate it in a heavily populated area than high in the atmosphere. Similarly, he noted, an attack on a substation with rifles would be much more likely than one with a homemade magnetic interference device.

Recent reports from government, industry, and security organizations indicate that the threat of cyberattacks on the grid by nation states, particularly Iran, has increased. Nayda Bartol, vice president of industry affairs and cybersecurity strategist of the trade association Utilities Telcom Council, said that the risk of an attack has grown together with the widespread adoption of smart grid technologies, and the concomitant rise in the number of connections to the remote systems that control electricity transmission. Smart meters have increased the vulnerability of the grid by providing a huge number of additional Internet-accessible points. “The Swiss cheese is bigger, and you have more opportunities to come in,” Bartol said.

Once-proprietary control systems have been supplanted by common information-technology hardware, software, and protocols, enabling hackers to more easily discover and understand them. An insufficient number of individuals, particularly at small utilities, have been trained in cybersecurity, and aging, unsecured legacy equipment will take years and billions to replace, she said.

Eyes in the sky

Three satellites that are located at L 1 —the Advanced Composition Explorer, Deep Space Climate Observatory, and SOHO—can provide 45 minutes at best of advance warning of a solar storm, Baker says. The actual time depends on the speed of the disturbance as it approaches Earth, Baker explains in an interview, and for a 3000 km/s CME like the July event, the warning would be less than 10 minutes. More routine storms take two to three days to reach Earth, he notes.

Round-the-clock solar observation by one or more dedicated monitoring satellites with real-time data transmission could increase warning time to as much as 12 to 14 hours, he says. Dedicated spacecraft might be able to determine the orientation of the magnetic fields when the CME is still close to the Sun, enhancing warnings for events that could be particularly damaging.

“The [power suppliers] would like to have eight hours warning—on the timescale of a work shift—so they can spin up enough reserve power and make plans for where an event might be hitting local time, and think about how they might divert current from one region to another or possibly selectively shut down parts of the grid,” Baker says. “That’s quite an elaborate process, and it would take a fair amount of time.”