The Survival of Emily Hunte by Julie Hopkins

Meet seventeen-year-old Emily Hunte, a teenager living in America during the Great War on Technology. When the attacks in Chicago started, her older sister and trained soldier, Amber smuggled her into a survivalist compound in the wilderness of Alaska—one of the few safe places left in the world. To survive in this cutthroat community, she has to take on the identity of the one person she swore she’d never become.