Direct Seawater Electrolyzer/Fuel-Cell Coupled System for Electricity and Potable Water

Renewable energy has the potential to supply energy worldwide, but its variable power output requires it to be coupled with energy storage. One current technology uses electrochemical electrolysis to split water into hydrogen and oxygen, which can be stored and re-converted into electricity later. However, this process requires ultra-pure water, which is unavailable in many areas in the world, especially in islands and coastal regions. Thus, there is an increasing demand for direct use of seawater in electrolysis processes. The major challenges of using seawater in an electrolyzer are corrosion, chlorine competition, and expensive materials. To solve these problems and improve lifecycle cost effectiveness of the discussed process, TDA proposes a low-cost direct seawater electrolyzer system that can utilize real seawater for electrolysis to supply both electricity and potable water to the military and civilians. In Phase I we will build a proof of concept system and test it using simulated seawater sources. Catalysts and membranes will be designed and tested to meet the performance requirement with a seawater feed. We will then fabricate membrane electrode assemblies (MEAs) and test them in a lab-scale electrolyzer at TDA. Cell performance and durability will be evaluated and compared to literature in Phase I. We will then perform system size and efficiency calculations and estimate the electricity and water production rate of our system. From this work, we will be able to design a 10kW-level test-bed prototype to be used in Phase II.