This slanderous capitalist lie is fabricated by the CIA on South Korean money, or the other way around. In North Korea, they do have all electricity they need. They simply use it for what is really important:
The extra current used at startup by most(with a small handful of exceptions) is less than that used by 1 second of normal operation. The idea it is less energy to keep them running is a myth(and yes, they busted this one on mythbusters, as well as other places).