Department of Homeland Security did a simulation what could happen if a hacker gains access to crucial parts of an electrical grid. The video was marked "Official Use Only" but seems to have leaked to The Associated Press. They then made themselves a small video. See some articles:

• The Raw Video
• The AP Video
• The AP Article (US Improperly Releases Threat Details)
• US Video Shows Hacker Hit on Power Grid

Have "fun"

Roger