As one of the few people who actually really enjoyed Season 1, I'm looking forward to it. That trailer was pretty great IMO.
I'm actually glad that they appear to be turning the power back off, since the lack of power was one of the things that made the show interesting.
At the same time it is a little annoying that they did turn it on, and then appear to be flipping the switch and turning it right back off again. I'm hoping they blow up The Tower, so we can focus on conflicts and motivations other than turning on the power.