- A “really crude” homemade bomb, described by an Arizona Department of Public Safety bomb squad as more like a big match than a grenade or explosive, charred the side of a 50,000-gallon diesel storage tank at the Valencia power delivery facility near Nogales, Arizona, but it injured no one and did not interrupt power delivery.
- Because the substation is part of critical infrastructure for Nogales, there is a full-scale response ongoing from the FBI and the Bureau of Alcohol, Tobacco, Firearms and Explosives.
- In 2013, an armed attack on the Metcalf Pacific Gas & Electric Corp. substation near San Jose, Calif., disabled cooling equipment and put 17 “costly and hard-to-repair transformers” out of service.
The Arizona substation is operated by UniSource Energy Services, a subsidiary of UNS Energy Corp, which provides electricity to about 93,000 people in Mohave and Santa Cruz counties.
Arizona Corporation Commission Chair Bob Stump called the Metcalf attack “a harbinger for more successful -- and serious -- attacks."
A recent analysis from the Battelle Institute urged the electric power sector and its regulators to work toward “comprehensive solutions” to grid threats such as natural disasters, cyberattacks, and assaults.
A Federal Energy Regulatory Commission-ordered plan to make the grid more secure by the North American Electric Reliability Corp. is now before the commission. The NERC proposal calls for each utility to assess vulnerabilities to its most critical transmission networks.
The Battelle study said a company-by-company security strategy should be combined with regional plans to avoid cascading outages. There is a cost-benefit consideration, with investments in redundancy and recovery technology potentially more cost effective than expenditures for infrastructure hardening.