Review on Supercritical Carbon Dioxide in Energy Storage Systems: Advances and Outlook

As the transition to low-carbon power generation accelerates, adopting renewable energy drives global research into energy storage systems (ESS) to address intermittency challenges and ensure a stable energy supply. ESS plays a vital role in off-grid and grid-connected communities, enabling a greater integration of renewable energy sources independent of the grid. Among various ESS technologies, supercritical carbon dioxide (sCO2) is emerging as a promising solution. This Account is structured into three main sections. The first section examines fossil fuels, their historical role in energy dependence, and their associated environmental and economic challenges. The second section analyzes energy storage technologies including mechanical, solar fuel cells, hydropower pumping, chemical, electrochemical, and superconducting magnetic storage systems. The third section focuses on sCO2 as an advanced medium for energy storage, along with an economic evaluation. Notably, among ESS options, underground adiabatic compressed carbon dioxide energy storage (UA-CCES) systems demonstrate exceptional efficiency by effectively recovering heat. The review concludes by highlighting the benefits of sCO2 technology in producing energy-dense materials for various applications. Advancing renewable energy is essential for mitigating environmental impact and achieving sustainable development. Innovations such as sCO2 and comprehensive economic evaluations of ESS, such as CCES, offer promising pathways to enhance energy efficiency and reduce carbon emissions. However, continued technological innovation and policy support are crucial for overcoming existing challenges and unlocking the full potential of these solutions.