Storage has become a premier cleantech investment opportunity. Ernst & Young reported that energy storage totaled more than a third of the US$1.1 billion US venture capital investment in cleantech for Q3 2011, which was the highest of any single sector that quarter. In 2009, investment bank Piper Jaffray projected that the energy storage market would be at least US$600 billion over the next 10 to 12 years. In the US alone, the Department of Energy ("DOE") has projected that over the next 5 to 10 years, between 10 and 100 gigawatts of energy storage will need to be installed, creating a US$35 billion industry. This article provides a brief overview of this fast-growing industry and describes recent developments in its regulatory treatment in the United States.