It's buried on the inside pages and toward the end of the story, but in the wake of the largest power-failure in US history the following couple of paragraphs in The Washington Post:
Many people think, though, that if terrorists want to switch America's lights off, there's an easier way to do it than hacking: bombs. Guerilla movements all over the world have made a specialty of blowing up power pylons. The industry contends that a single bomb, even on a vital transmission corridor, likely wouldn't knock out a big chunk of the electrical system, but it has long acknowledged that a coordinated attack involving bombs in several places might do so. Last week's events may force a new assessment of whether terrorists could, by design, hit the system in just the right place or places to produce a large blackout.
"What you need to worry about is some guy with a little palm-sized piece of C-4," a plastic explosive, said Lauren Weinstein, a computer-security expert in California who is skeptical of a cyberthreat to the power grid. "The problems on the low-tech side are where the real risks are. Those are really intractable problems, and they're really scary, because people don't know how to fix them."