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By Jesse Berst

Here's the truly scary part – two of the incidents occurred where companies had quarantined their networks. Despite the so-called "air gap," malicious software was introduced via thumb drive. In one case, a third-party technician used a USB drive to upload software updates, not knowing the device was infected with malware. In that case, the infection delayed a power plant's startup by three weeks.

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Jesse Berst is the founder and chief analyst of Smart Grid News.com, the industry's oldest and largest smart grid site. A frequent keynoter at industry events in the U.S. and abroad, he also serves on advisory committees for Pacific Northwest National Laboratory and the Institute for Electric Efficiency. He often provides strategic consulting to large corporations and venture-backed startups. He is a member of the advisory boards of GridGlo and Calico Energy Services.