Alkaline Water Electrolyzer for Improved Power-To-Gas System
Advanced energy storage promises to play a key role in modernizing our nation’s electricity grid to enable the integration of increasing amounts of renewables, improve operating capabilities, enhance reliability, allow deferral of infrastructure investments and provide backup power during emergencies. While batteries may soon provide short-duration energy storage at reasonable costs, they do not perform as well for longer durations, for example multi-day storage. One alternative is power-to-gas technologies, such as water electrolyzers that convert electricity to chemical energy in hydrogen (H2), which can then be stored in pressurized tanks. These approaches provide excellent longer-term storage at a lower cost, but suffer from poor roundtrip efficiencies relative to electrical energy storage in batteries.
Project Innovation + Advantages:
The team led by Dioxide Materials will develop an alkaline water electrolyzer for an improved power-to-gas system. The team’s electrochemical cells are composed of an anode, a cathode, and a membrane that allows anions to pass through, while being electrically insulating. High-conductivity anion exchange membranes are rare and often do not have the chemical or mechanical stability to withstand H2 production at elevated pressures. Therefore, the project is focused on developing an anion exchange membrane that is low-cost, is manufacturable in a scaleable process, and has sufficient conductivity, chemical stability, and mechanical strength. Moreover, by operating at alkaline instead of acidic conditions, the electrochemical cells do not need to use expensive precious metal catalysts, which most systems require to prevent corrosion. Dioxide Materials estimates that operating under alkaline conditions could lead to a 10x lower electrolyzer stack cost due to higher current densities and lower material costs (i.e. non-precious metals). The system will be compatible with intermittent energy sources because it can operate at lower temperatures than competiting technologies, thus allowing startup times on the order of seconds.
If successful, this technology could yield greatly improved water electrolyzers, which could enable low-cost energy storage compatible with intermittent renewable energy sources, such as solar and wind power.
Storing energy from intermittent renewables over long durations in a cost-effective manner could reduce demand on the electric grid, while produced H2 or derived liquids could provide a low-carbon alternative to fossil fuels for transportation.
Clean energy storage technologies could allow high penetration of emissions-free renewable power.
The team’s innovations could reduce the cost of long-term energy storage and therefore enable renewables to be more cost competitive with conventional generation sources.