Carbon Footprint and Energy Analysis of a Mixed Metal Oxide Thermochemical Energy Storage Technology

Strategies to decarbonize electricity generation and distribution require energy storage technologies that deliver power during periods of downtime in variable renewable energy sources, such as wind and solar PV. Ideally, energy storage technologies should not add significantly to the carbon footprint of the renewable electricity grid. In this study, we determine the carbon footprint and cumulative energy demand for a new thermochemical energy storage technology using an environmental life cycle assessment (LCA). The technology is based on abundant mixed metal oxide energy storage material that operates over a 20-year lifetime with periodic renewal of the storage material. This energy storage technology can deliver power over a time that is intermediate in the range between short- and long-duration energy storage. Input data for the operation were derived from industry demonstration trials and engineering calculations. The results indicate that the contribution of the process infrastructure and energy storage material manufacture and recycle contribute 36.2 kg CO2 eq/MWh-e delivered to the grid, a value on par or lower compared to Li-ion battery and vanadium redox flow battery storage, and much lower than conventional fossil-based power (US coal 1090: US natural gas 736: US grid 502.6 kg CO2 eq/MWh-e). Technology performance parameters such as round-trip efficiency and efficiency loss factor significantly affected the LCA results, shining a light on areas for improvement.