The biggest threat to the US electricity grid? The solar system

solar storm US electricity grid
A solar storm hitting earth would knock out electricity and water supplies and the US economy cost trillions of dollars

The solar system presents a much greater threat to the US electricity grid than cyber security and natural disasters, a group of space physicians told the House Science, Space and Technology Committee in Washington last week.

The possibility of a solar superstorm wreaking havoc with the US electricity grid is not a question of if, but when, said Daniel Baker, a professor of planetary and space physics at the University of Colorado, Boulder.

Mr Baker was one of several witnesses briefing the federal committee on the range of natural and manmade threats to the US electricity grid, reports Physics Today.

The professor cited how a “ferocious” coronal mass ejection that narrowly missed Earth in July 2012 would have caused massive power blackouts, disabling everything that uses electricity, knocked out municipal water supplies, and cost trillions of dollars.

Had the solar storm in 2012 occurred one week earlier, the world “would still be picking up the pieces”, the professor said.

At present, the US has three satellites that can provide 45 minutes advance warning of a solar storm, Baker says.

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.

Baker said: “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.

“That’s quite an elaborate process, and it would take a fair amount of time.”

US electricity grid – manmade threats

The scientist told the committee that manmade threats to the US electricity grid include an electromagnetic pulse 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 threat from an electromagnetic pulse 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.

However, Granger Morgan, an engineering and public policy professor at Carnegie Mellon University, downplayed the threat by saying that a terrorist organisation 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.

High-voltage transformers

Phyisics Today reports that much of the concern over the US electricity grid’s physical vulnerability is based on having 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.

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 concludes.