Low Cost Large Scale PEM Electrolysis for Renewable Energy Storage

Solar and wind energy are the most likely candidates to meet our future energy needs based on the available capacity. The problem is that these renewable sources are not consistently accessible, and thus storage must be an integral part of the energy solution. Hydrogen generation via proton exchange membrane (PEM) water electrolysis is one attractive solution, but the life cycle cost of the electrolyzer must be reduced in order to meet the DOE targets. The membrane electrode assembly represents over 1/3 of the cell stack cost, while the membrane ionic resistance contributes approximately half of the stack efficiency losses. Therefore, reducing the membrane thickness is a key area for research, since it can reduce the raw material costs as well as the electrical operating costs (which can represent up to 2/3 of the life cycle costs). The proposed project will address this area through investigation of thinner, reinforced membranes for improved mechanical strength while maintaining high proton conductivity. Phase 1 will focus on processing development to achieve a robust membrane electrode assembly, with proof of concept of the required stack efficiency at the 0.1 ft2 cell level. A final test will be conducted at a 0.6 ft2 stack size at the end of the program, which will feed cost analysis based on the H2A model. Phase 2 will focus on demonstration of scalability of the improved membranes to full size cell stacks, with fabrication of a 300 psi electrolyzer based on the 0.6 ft2 stack. This system will operate for at least 1000 hours, with a goal of demonstrating >69% efficiency. Analysis of operation projected to 50,000 kg/day will be performed, including analysis of greenhouse gas and petroleum reductions that will occur with the successful implementation of the proposed technology. Commercial Applications and Other Benefits: This research and development effort is designed to transform hydrogen-based energy storage into an enabling technology for the reduction of fossil fuel use by overcoming the present economic constraints preventing its widespread application. Proton