Early in 2018, Fortress Power released two energy storage systems in the United States – a 10 kilowatt-hour (kWh) and a 15 kWh model. Their foray into an increasingly packed residential storage system market is with a different type of chemistry – lithium ferrite phosphate – than many other options available on the market. EnergySage sat down for a Q&A with Fortress Power to learn more about the company, why customers should consider energy storage, and how Fortress Power batteries differ from other brands in the market. (Interview has been edited for brevity and clarity.)