He just turned off the switch in the breaker, right behind the meter. The meter itself is still hooked up, so from the power company's perspective, he has an account and everything.

At least that's how I read the article he wrote last year:

Nevertheless, I opened the main circuit, disconnecting my apartment from the grid and committing myself to solving what problems arose as they came. As I type these words in January, I’m in my eighth month. My Con-Ed bills continue to show zero kilowatt-hours.