The technoeconomics of the hydrogen-bromine flow battery are investigated. Using existing performance data the operating conditions were optimized to minimize the levelized cost of electricity using individual component costs for the flow battery stack and other system units. Several different configurations were evaluated including use of a bromine complexing agent to reduce membrane requirements. Sensitivity analysis of cost is used to identify the system elements most strongly influencing the economics. The stack lifetime and round-trip efficiency of the cell are identified as major factors on the levelized cost of electricity, along with capital components related to hydrogen storage, the bipolar plate, and the membrane. Assuming that an electrocatalyst and membrane with a lifetime of 2000 cycles can be identified, the lowest cost market entry system capital is 220 $ kWh(-1) for a 4 h discharge system and for a charging energy cost of 0.04 $ kWh(-1) the levelized cost of the electricity delivered is 0.40 $ kWh(-1). With systems manufactured at large scales these costs are expected to be lower. (c) 2015 Elsevier B.V. All rights reserved.