Ultra-supercritical Energy Storage

Abstract

We develop an electro-geothermal battery for large scale ultra-supercritical energy storage. The technology relies on the proven concept of underground natural gas storage extended for the supercritical CO2 and H2O cycle. Storing gas in sedimentary formations is already one of the largest-scale proven technologies for energy storage. New ultra-supercritical H2O and CO2 generators operate at extreme temperatures ( more than 600°C), achieve close to 50% efficiency and are proposed as the next technology to lower emissions of conventional power plants. These generators put forward new challenges for energy storage especially when they are used in conjunction with renewable energy sources such as Concentrated Solar Power. We test the ultra-supercritical reaction, deformation and fluid flow of targeted reservoir rocks in bespoke X-Ray and Neutron beam transparent fluid flow and deformation cells. Our goal is to facilitate the design of ultra-supercritical generators that store supercritical CO2 efficiently. We aim at identifying suitable reservoirs that can store and dispatch large amounts of energy without the need of an intermediate heat transfer medium such as molten salt or graphite.