This reminds me of both Lois Lowry's Giver, Gathering Blue, and Messenger as well as Margaret Peterson Haddix's Running Out of Time. This is by no means bad. City of Ember is written as young adult sci-fi, or perhaps just young adult fiction, but it is still a good read.
It's about a city entirely in darkness, powered by an underwater generator powered by the river. They are running out of resources, however, and the lights often flicker and the blackouts are getting longer and longer. It's told from the perspective of a 12-year-old girl and how she tries to solve this problem for herself, her family, and her city.
It's easy and a fast read. I think I would have enjoyed it a lot as a child; I did enjoy it now. There are a few things that are rather juvenile in her writing and the plot, but it is juvenile, so it's all good. I would recommend this book to anyone who likes the aforementioned books and doesn't consider any reading to be 'below them.'