CO2-Based Energy Storage

Detailed overview of innovation with sample startups and prominent university research

What it is

CO2-based energy storage technologies utilize carbon dioxide (CO2) as a working fluid or storage medium to store and release energy. These technologies offer a sustainable and potentially carbon-negative approach to energy storage, as they can utilize captured CO2 emissions from industrial processes or directly from the atmosphere.

Impact on climate action

CO2-Based Energy Storage in Thermal & Mechanical Storage advances climate action by converting carbon dioxide emissions into a useful resource for energy storage. By capturing and storing CO2 in a closed-loop system, this innovation reduces greenhouse gas emissions, promotes renewable energy integration, and mitigates climate change impacts.


  • Liquid CO2 Energy Storage: This technology involves compressing and liquefying CO2, storing it in insulated tanks, and then expanding it through a turbine or expander to generate electricity when needed.
  • Supercritical CO2 Energy Storage: Supercritical CO2 is a fluid state of CO2 that exhibits properties of both a liquid and a gas. It can be used as a working fluid in energy storage systems, offering advantages in terms of efficiency and energy density.
  • CO2-Based Thermal Energy Storage: CO2 can be used as a heat transfer fluid and storage medium in thermal energy storage systems, similar to molten salt in concentrated solar power (CSP) plants.
  • CO2 Conversion and Utilization: Captured CO2 can be converted into fuels, chemicals, or building materials, effectively storing energy in the form of chemical bonds.

TRL : 4-6 (depending on the specific technology)

Prominent Innovation themes

  • Advanced CO2 Compression and Liquefaction Technologies: Researchers are developing more efficient and cost-effective methods for compressing and liquefying CO2, improving the feasibility of liquid CO2 energy storage systems.
  • Supercritical CO2 Power Cycles: Innovations in supercritical CO2 power cycles are improving efficiency and reducing the size and cost of these systems.
  • CO2-Based Thermal Energy Storage Materials: Researchers are developing new materials and designs for CO2-based thermal energy storage systems, focusing on improving heat transfer and storage capacity.
  • CO2 Conversion and Utilization Technologies: Advancements in CO2 conversion technologies are expanding the range of products that can be produced from captured CO2, creating new markets and economic opportunities.

Other Innovation Subthemes

  • CO2-Based Energy Storage Systems
  • Liquid CO2 Energy Storage
  • Supercritical CO2 Power Cycles
  • CO2-Based Thermal Energy Storage
  • CO2 Conversion Technologies
  • Advanced CO2 Compression Methods
  • Supercritical CO2 Innovations
  • CO2 Thermal Storage Materials
  • CO2 Utilization Advancements
  • Energy Dome Technology
  • Echogen Power Systems
  • Grid-Scale CO2 Storage

Sample Global Startups and Companies

  1. Energy Dome:
    • Technology Enhancement: Energy Dome focuses on CO2-based energy storage solutions, utilizing carbon dioxide (CO2) as a medium for storing renewable energy. Their technology involves capturing CO2 emissions from industrial sources or the atmosphere and converting them into high-pressure or liquid form for storage. This stored CO2 can then be released to generate power through various processes, such as combustion or thermodynamic cycles.
    • Uniqueness of the Startup: Energy Dome stands out for its innovative approach to energy storage, leveraging CO2 as a versatile and abundant medium. By repurposing CO2 emissions for energy storage, they address both the challenge of carbon emissions and the need for scalable and sustainable energy storage solutions.
    • End-User Segments Addressing: Energy Dome serves a wide range of industries, including power generation, manufacturing, and transportation, seeking innovative solutions for carbon capture and energy storage. Their CO2-based energy storage technology offers a flexible and cost-effective alternative to conventional energy storage methods, supporting the transition to a low-carbon economy.
  2. Echogen Power Systems:
    • Technology Enhancement: Echogen Power Systems specializes in CO2-based energy storage and power generation solutions, focusing on supercritical CO2 (sCO2) cycles. Their technology utilizes CO2 as a working fluid in closed-loop cycles for energy storage and power generation applications. By leveraging the unique properties of sCO2, such as high density and thermal conductivity, they offer efficient and compact energy storage systems.
    • Uniqueness of the Startup: Echogen Power Systems stands out for its expertise in sCO2 technology and its applications in energy storage and power generation. Their solutions enable high-efficiency energy conversion and grid-scale energy storage, addressing the challenges of intermittent renewable energy sources and grid stability.
    • End-User Segments Addressing: Echogen Power Systems serves utility companies, renewable energy developers, and industrial customers seeking advanced energy storage and power generation solutions. Their CO2-based energy storage systems are deployed in various applications, including concentrated solar power (CSP), waste heat recovery, and grid-scale energy storage projects.
  3. CO2 Solutions:
    • Technology Enhancement: CO2 Solutions specializes in carbon capture technology, including CO2 utilization and storage solutions. Their technology involves capturing CO2 emissions from industrial sources and converting them into valuable products or storing them in geological formations. By leveraging enzymatic processes and proprietary solvent systems, they offer cost-effective and scalable solutions for carbon capture and storage (CCS).
    • Uniqueness of the Startup: CO2 Solutions stands out for its innovative approach to carbon capture and utilization, focusing on enzymatic processes and low-cost solvent systems. Their technology offers advantages such as reduced energy consumption, lower operating costs, and enhanced environmental performance compared to conventional CCS methods.
    • End-User Segments Addressing: CO2 Solutions serves industries with high CO2 emissions, such as power generation, cement production, and oil and gas refining, seeking sustainable solutions for carbon management. Their CO2 capture and storage technology enables companies to meet regulatory requirements, reduce carbon footprint, and transition to low-carbon operations.

Sample Research At Top-Tier Universities

  1. Massachusetts Institute of Technology (MIT):
    • Research Focus: MIT is a frontrunner in researching CO2-Based Energy Storage as part of Thermal & Mechanical Storage systems. Their research concentrates on utilizing carbon dioxide (CO2) as a medium for thermal and mechanical energy storage, exploring various chemical and physical processes for efficient energy capture, storage, and release.
    • Uniqueness: MIT’s research explores novel methods for capturing and sequestering CO2 emissions from industrial processes and power plants, while simultaneously utilizing the captured CO2 as a working fluid in thermal and mechanical storage systems. They investigate the thermochemical conversion of CO2 into high-energy-density fuels or solid-state materials, as well as the use of CO2 as a heat transfer fluid in advanced heat exchanger designs.
    • End-use Applications: The outcomes of MIT’s research have applications in grid-scale energy storage, industrial heat recovery, and carbon-neutral power generation. By integrating CO2-based energy storage with renewable energy sources and carbon capture technologies, MIT’s research contributes to reducing greenhouse gas emissions, enhancing energy security, and enabling the transition to a sustainable energy future.
  2. National Renewable Energy Laboratory (NREL):
    • Research Focus: NREL conducts pioneering research on CO2-Based Energy Storage within the realm of Thermal & Mechanical Storage technologies. Their research aims to develop innovative CO2-based storage solutions that enable efficient and cost-effective storage of renewable energy, particularly excess electricity generated from intermittent sources such as wind and solar.
    • Uniqueness: NREL’s research encompasses the development of advanced materials, processes, and system architectures for capturing, storing, and utilizing CO2 as a storage medium for both thermal and mechanical energy applications. They investigate the integration of CO2-based storage systems with concentrated solar power (CSP), waste heat recovery, and industrial processes to provide dispatchable and flexible energy services.
    • End-use Applications: The outcomes of NREL’s research find applications in renewable energy integration, grid stabilization, and industrial decarbonization. By advancing CO2-based energy storage technologies, NREL’s research contributes to improving the reliability, resilience, and sustainability of the energy system, while also addressing climate change mitigation goals.
  3. University of California, Berkeley:
    • Research Focus: UC Berkeley is engaged in innovative research on CO2-Based Energy Storage, focusing on exploring novel materials, reactor designs, and system architectures for storing and utilizing CO2 as a medium for thermal and mechanical energy storage applications.
    • Uniqueness: Their research spans fundamental studies on CO2 capture, storage, and conversion processes, as well as applied research on integrating CO2-based storage systems with renewable energy sources, district heating and cooling networks, and industrial processes. They investigate the techno-economic feasibility, environmental impact, and scalability of CO2-based storage solutions across different end-use sectors.
    • End-use Applications: The outcomes of UC Berkeley’s research have applications in building energy management, district energy systems, and microgrid resilience. By developing CO2-based energy storage technologies, UC Berkeley’s research supports the transition to a low-carbon energy economy, enhancing energy efficiency, reducing emissions, and promoting sustainable development.

commercial_img Commercial Implementation

CO2-based energy storage technologies are still in the early stages of commercialization, with a limited number of pilot projects and demonstration plants in operation. However, the technology is gaining increasing interest as a potential solution for long-duration energy storage and grid-scale applications.