Protecting substations and transformers after the PG&E Metcalf attack.
William Atkinson is a Fortnightly contributor based in Carterville, Ill.
Utilities and policymakers have focused increasing attention over the past decade on electric grid cybersecurity. By comparison, less attention has been paid to initiatives designed to prevent physical attacks on electric facilities. However, a 2012 report by the National Research Council, titled "Terrorism and the Electric Power Delivery System," found that high-voltage transformers "are the single most vulnerable component of the transmission and distribution system."
That observation was confirmed by reports of a physical attack on the PG&E Metcalf transmission substation in San Jose, Calif., on April 16, 2013. The attack wasn't widely publicized outside of the electric utility industry until The Wall Street Journal reported it in early February 2014.
FBI investigators in San Jose found evidence of a carefully planned attack. Before the substation was attacked, the culprits reportedly snipped AT&T fiber optic lines to knock out phone service, including the 911 emergency system. Then, multiple gunmen using assault rifles fired between 100 and 150 rounds into the substation equipment, disabling 17 of the 20 large transformers. Because the substation was protected only by a chain link fence, the snipers had clear shots at the cooling fins, thus draining oil from the transformers.