Blackout (power)
A blackout is the loss of the electricity supplied to a certain area.

In 2268, while seeking not to violate the Prime Directive or code term condition green given to him by a captured Captain James T. Kirk which ordered him not to interfere, Chief Engineer Montgomery Scott ordered Pavel Chekov to pinpoint  source locations — type, power, load factors, and how much tractor beams would have to pull to overload them — in a planned attempt to frighten the natives of  the planet 892-IV. It was later determined that the resulting temporary blackout in the large city had no interference with the society and it saved the lives of Kirk and the rest of his landing party: Lieutenant Commander Spock and Chief Medical Officer Leonard McCoy. ()

During the Dominion cold war, Admiral Leyton ordered Red Squad to sabotage the global power grid on Earth, causing the whole planet to suffer a blackout. ()

Throughout the Battle of Cardassia, the Cardassian Rebellion sabotaged Cardassia Prime's communications, transportation and power systems, causing a planet-wide blackout. This disabled the Female Changeling's ability to command the Dominion ships during the battle, ultimately resulting in the allies' victory. ()

Memorable quotes 
"It's dark." 
 - Crewman Celes

See also 

Energy