An EMP isn’t the only way to take down the grid. Simultaneous, coordinated, distributed attacks on multiple transformer substations could be very effective at causing mass blackouts, if enough transformers were seriously damaged or disabled.

I remember rumors about a sniper attack on a California substation last year. But now the attack is more than just a rumor: the details of what happened last April 16 at the PG&E Metcalf transmission substation in Silicon Valley have just been publicly revealed.

According to Business Insider:

The Wall Street Journal’s Rebecca Smith reports that a former Federal Energy Regulatory Commission chairman is acknowledging for the first time that a group of snipers shot up a Silicon Valley substation for 19 minutes last year, knocking out 17 transformers before slipping away into the night. The attack was “the most significant incident of domestic terrorism involving the grid that has ever occurred” in the U.S., Jon Wellinghoff, who was chairman of the Federal Energy Regulatory Commission at the time, told Smith. A blackout was avoided thanks to quick-thinking utility workers, who rerouted power around the site and asked power plants in Silicon Valley to produce more electricity. But the substation was knocked out for a month. The FBI says it doesn’t believe a terrorist organization caused the attack but that it continues to investigate the incident. Smith and colleague Tom McGinty assembled a detailed chronology of the attack that includes some amazing details, including more than 100 fingerprint-free shell casings similar to ones used by AK-47s that were found at the site and small piles of rocks that appeared to have been left by an advance scout to tell the attackers where to get the best shots.

Excerpts from The Wall Street Journal article:

Assault on California Power Station Raises Alarm on Potential for Terrorism SAN JOSE, Calif.—The attack began just before 1 a.m. on April 16 last year, when someone slipped into an underground vault not far from a busy freeway and cut telephone cables. Within half an hour, snipers opened fire on a nearby electrical substation. Shooting for 19 minutes, they surgically knocked out 17 giant transformers that funnel power to Silicon Valley. A minute before a police car arrived, the shooters disappeared into the night. To avoid a blackout, electric-grid officials rerouted power around the site and asked power plants in Silicon Valley to produce more electricity. But it took utility workers 27 days to make repairs and bring the substation back to life. Nobody has been arrested or charged in the attack at PG&E Corp.’s Metcalf transmission substation. It is an incident of which few Americans are aware. But one former federal regulator is calling it a terrorist act that, if it were widely replicated across the country, could take down the U.S. electric grid and black out much of the country. The attack was “the most significant incident of domestic terrorism involving the grid that has ever occurred” in the U.S., said Jon Wellinghoff, who was chairman of the Federal Energy Regulatory Commission at the time. The Federal Bureau of Investigation doesn’t think a terrorist organization caused the Metcalf attack, said a spokesman for the FBI in San Francisco. Investigators are “continuing to sift through the evidence,” he said. Some people in the utility industry share Mr. Wellinghoff’s concerns, including a former official at PG&E, Metcalf’s owner, who told an industry gathering in November he feared the incident could have been a dress rehearsal for a larger event. “This wasn’t an incident where Billy-Bob and Joe decided, after a few brewskis, to come in and shoot up a substation,” Mark Johnson, retired vice president of transmission for PG&E, told the utility security conference, according to a video of his presentation. “This was an event that was well thought out, well planned and they targeted certain components.” When reached, Mr. Johnson declined to comment further. […] Mr. Wellinghoff said a FERC analysis found that if a surprisingly small number of U.S. substations were knocked out at once, that could destabilize the system enough to cause a blackout that could encompass most of the U.S.

It turns out that low-tech attacks are more of a concern than cyberattacks:

“A lot of people in the electric industry have been distracted by cybersecurity threats,” said Stephen Berberich, chief executive of the California Independent System Operator, which runs much of the high-voltage transmission system for the utilities. He said that physical attacks pose a “big, if not bigger” menace. […] To some, the Metcalf incident has lifted the discussion of serious U.S. grid attacks beyond the theoretical. “The breadth and depth of the attack was unprecedented” in the U.S., said Rich Lordan, senior technical executive for the Electric Power Research Institute. The motivation, he said, “appears to be preparation for an act of war.”

But the FBI doesn’t think it’s related to terrorism.

Hmm. What could it be, then? Workplace violence, perhaps?

Nah. It must have been space aliens. That’s it!

But the electric utility called it vandalism:

In a news release, PG&E said the substation had been hit by vandals. It has since confirmed 17 transformers were knocked out. Mr. Wellinghoff, then chairman of FERC, said that after he heard about the scope of the attack, he flew to California, bringing with him experts from the U.S. Navy’s Dahlgren Surface Warfare Center in Virginia, which trains Navy SEALs. After walking the site with PG&E officials and FBI agents, Mr. Wellinghoff said, the military experts told him it looked like a professional job. In addition to fingerprint-free shell casings, they pointed out small piles of rocks, which they said could have been left by an advance scout to tell the attackers where to get the best shots. “They said it was a targeting package just like they would put together for an attack,” Mr. Wellinghoff said.

Like the New Year’s Day explosion and fire in Minneapolis, the Metcalf substation attack was swept under the rug. It just didn’t stay there.

How many other incidents are under there? That rug is starting to look pretty lumpy…