The City of Ember -- Jeanne DuPrau

In the city of Ember, the sky was always dark.  The only light came from great flood lamps mounted on the buildings and at the tops of poles in the middle of the larger squares.  When the lights were on, they cast a yellowish glow over the streets; people walking by threw long shadows that shortened and then stretched out again.  When the lights were off, as they were between nine at night and six in the morning, the city was so dark that people might as well been wearing blindfolds.

In the city of Ember, there are periodic blackouts--the lights go out in the middle of the day and people stand stock still, hoping that that the lights will come back on.  The blackouts are getting more and more frequent.

It's a kinder, gentler dystopia novel.  There's no euthanasia, cloning, or violent death.  Just greed, fear and lies. 

Pretty fun.  And there's a sequel, too.