The hacker responsible for a series of Wisconsin power failures five years ago was sentenced to seven more years in federal prison this week.

Joseph D. Konopka, 29, is already servicing a 13-year federal sentence after pleading guilty to chemical weapons possession in 2002, the Associated Press reported.

A former systems administrator who called himself "Dr. Chaos" online, Konopka was caught storing cyanide near a Chicago subway. He plead guilty to 11 felonies in August, including conspiracy, arson and creating counterfeit software, the AP reported.

Along with six juveniles known as his "Realm of Chaos" who also pleaded guilty, Konopka was responsible for 28 power outages and 20 interruptions – at a cost of $800,000 – in 1999.