Stationary applications such as utility grids and industrial sites require storage applications that have the ability to combine high power and heavy use, going through multiple deep cycles per day, with a long lifetime and maximum safety. In this project, a novel flow battery will be developed and validated. The focus is on keeping the levelized cost of energy storage as low as possible. This is achieved by utilizing a low-cost electrolyte, a low-cost yet high-performing stack, novel membranes, and a novel battery management system combined with advanced sensors. Great care will be taken to ensure optimal sustainability regarding choice of materials, second-life, and recycling.