AEM Water Electrolyzer for Hydrogen Production from Offshore Wind

Hydrogen can decarbonize many carbonintensive sectors, increase national energy security, and provide flexibility to our power grid. Today, more than 95% of hydrogen is produced from cheap fossil fuels, contributing to more than 2% of global greenhouse gas emissions. Green hydrogen production by coupling water electrolyzers to offshore wind is the key for decarbonizing the economy. Directly coupling offshore wind with water electrolyzers for hydrogen production offers unique advantages, particularly related to reducing the cost of electric grid connections and reducing energy losses, by transporting hydrogen over long distances rather than transporting electricity. Although water electrolysis is a relatively well established technology in specialty applications, there are not currently any water electrolyzers deployed on offshore wind farms. One of the lessdiscussed requirements of lowtemperature water electrolyzer technologies is the availability of highly pure water feeds. The high capital cost and energy requirement of desalination systems, such as reverse osmosis, can become a bottleneck to realizing offshore wind coupled to water electrolysis. Instead, using seawater as the feedstock to water electrolysis can enable a lowcost, small footprint, and energy efficient green hydrogen production platform. In Phase I of this project, Alchemr demonstrated the robustness of its benchtop anion exchange membrane electrolyzer system under conditions that the system would be subject to when integrated with an offshore wind turbine. In addition, we experimentally evaluated various electrodes and catalyst materials in Phase I to feed our electrolyzer system with seawater. However, one of the key catalytic challenges which still should be addressed for seawater electrolysis is the competition between anodic chlorine evolution reaction and the oxygen evolution reaction on the anode electrode as well as reducing cell degradation in seawater corrosive environment. We successfully ran our 5 cm2 cell for more than 330 hours at <1.9 V. However, this was done at low current densities 30 mA cm2. In Phase II, we propose to evaluate more sophisticated catalyst materials and electrode preparation methods to improve cell performance. In collaboration with the University of Connecticut, Alchemr will develop a highperformance and durable anode electrode using the unique reactive spray deposition technology, based on the successful material identified in Phase I. We will also produce new oxygen evolution reaction selective catalysts e.g., MnMo oxides, MnMoW oxides, and NiFelayered double hydroxide. We will further develop a stable anode flowfield/current collector to enable increased current density and reduce cell degradation rates for seawater electrolysis. On the other hand, Phase I tests were performed on 5 cm2 and 25 cm2 cells. To increase hydrogen production, in Phase II, we propose investigating our electrolyzer's electrochemical behavior in a 3cell single stack with an active area of 750 cm2 250 cm2 per cell and seawater as the electrolyzer feedstock. Lastly, we propose to improve the technoeconomic model that we established in Phase I to include maintenance costs required due to running seawater through the system rather than purified water.