From 2004 to 2009, Epstein investigated energy production and consumption in the United States, photographing in and around various energy production sites. This series, titled "American Power,"questions the meaning and make-up of power—electrical and political. Epstein made a monograph of the American Power pictures (2009), in which he wrote that he was often stopped by corporate security guards and once interrogated by the FBI for standing on public streets and pointing his camera at energy infrastructure. The large-scale prints from this series have been exhibited worldwide.