Earth Battery Energy Storage replaces air-combustion with oxy-combustion, which produces just CO₂ and steam, which are easy to separate, thus virtually eliminating more expensive CO₂/N₂ separation costs. Oxygen from air is produced when the cost of electricity is low. Similarly, all the combustion is done when the cost of electricity is low, and the CO₂ produced is compressed using the low-cost electricity. The heat produced is stored in granular media (either above or below ground) and used throughout the day to supply heat or produce power. This time shifting allows for stored energy to be released when electricity is high, usually during the daytime. This combination of oxy-combustion and heat storage allows us to separate the processes of combustion and power production, thus allowing greater flexibility in design and operation of the heat/power plants.

Earth Battery Energy Storage can make very efficient use of low-temperature heat sources, such as solar thermal or geothermal, both of which can be used in series with conventional power plants to reduce fuel consumption, thereby reducing CO₂ production.

Publication: 

Buscheck, T. A., & Upadhye, R. S. (2021). Hybrid-energy approach enabled by heat storage and oxy-combustion to generate electricity with near-zero or negative CO2 emissions. Energy Conversion and Management, 244. (https://doi.org/10.1016/j.enconman.2021.114496)