The Energy Dome CO2 Battery: Closed Loop System Can Last 30+ Years with No Degradation

 

     An interesting new grid-scale energy storage solution is emerging that uses CO2 phase changes to store, charge, and discharge energy. This is another project that utilizes supercritical CO2 as a working fluid. However, the way it is used here is innovative. Italian company Energy Dome has developed the Energy Dome which holds the CO2. The system operates in a closed loop. It offers long-duration energy storage, for up to 24 hours. Back in 2022 Energy Dome explained:

 

“CO2 is the perfect fluid to store energy cost effectively in a closed thermodynamic process as it is one of the few gases that can be condensed and stored as a liquid under pressure at ambient temperature,” Energy Dome explains. “This allows for high density energy storage without the need to go at extreme cryogenic temperatures.”

 

“In charging mode, the CO2 is drawn from an atmospheric gasholder, the Dome, compressed and then stored under pressure at ambient temperature in a high density supercritical or liquid state,” they add. “When energy needs to be released, the CO2 is evaporated and expanded into a turbine, and then returned back to the atmospheric gasholder, ready for the next charging cycle.”

 

     While similar results can be obtained with compressed air systems or liquid air systems, the fact that CO2 can be stored at ambient temps as a liquid reduces costs over those systems. Back in 2022, Energy Dome was taking pre-orders for their tech all over the world of facilities 100-200MW in size. This is big energy storage. Energy Dome claims their tech can be deployed at half the cost of lithium-ion batteries.

 

     The new project is the Columbia Energy Storage Project in Pacific, Wisconsin. The project is hosted by US gas and electricity supplier Alliant Energy. Clean Technica notes that the source of the CO2 is unknown. One might speculate that CO2 of sufficient purity captured from Midwest ethanol refining plants is a potential source. They also did not note how much CO2 is needed for each similar-sized closed-loop system. In July Energy Dome was awarded $7 million from the DOE’s Office of Clean Energy Demonstrations. The grant covers the early part of Phase 1 of the project for 16-22 months.  It will be the first Energy Dome facility in North America, once the application gets final approval from regulators. Construction should begin in 2026, with plans to be online by 2027.

    

     The closed-loop system is expected to last 30+ years with no degradation, compared to lithium-ion grid batteries which degrade through time and have a lifespan of about 12 years. The company notes that the process uses only water, steel, and CO2 to operate. The pilot project unit in Sardinia, Italy was 20MW in size. The Wisconsin project can be scaled up to 200MW utilizing 10 20MW units.  They also note that all tech components are readily available and do not need to be sourced from China like lithium, other metals, and their processing. They emphasize that off-the-shelf equipment, standard components, modularity, and scalability are features of the Energy Dome system. Alliant Energy notes that the project can “deliver enough electricity to power approximately 18,000 Wisconsin homes for 10 hours on a single charge” and that it can complement lithium-ion storage:

 

“This new technology can work in tandem with shorter-duration lithium-ion batteries. While lithium-ion batteries are highly efficient and can help meet day-to-day peak customer demands, they’re less practical for storage longer than 10 hours.”

 

     The data below summarizes the CO2 battery’s operation.

 

     The next data shows the grid services that the long-duration Energy Dome Co2 battery can offer, and the table below shows some comparisons of the Energy Dome with lithium-ion batteries.

 

 

 

 

      The video animation below shows the charging and discharging cycles. One can see that the large tank of ambient gaseous CO2 can be compressed into supercritical CO2 in vessels of much smaller size. 

 

 

References:

New technology offers mind-blowing breakthrough for storing energy: 'Very efficient and a good source of power'. Jon Turi. The Cool Down. September 24, 2024. New technology offers mind-blowing breakthrough for storing energy: 'Very efficient and a good source of power' (msn.com)

CO2 Battery. Energy Dome. CO2 Battery - Energy Dome

Giant Bubble Of CO2 To Store Renewable Energy For At Least 10 Hours. Tina Casey. Clean Technica. August 26, 2024. Giant Bubble Of CO2 For Long Duration Energy Storage - CleanTechnica

New technology boosts grid reliability. Grant Barton. Alliant Energy. November 3, 2023. Alliant Energy - New technology boosts grid reliability

Instant Long Duration Energy Storage: Just Add Carbon Dioxide. Tina Casey. Clean Technica. April 22, 2022. Instant Long Duration Energy Storage: Just Add Carbon Dioxide (cleantechnica.com)

Columbia Energy Storage Project. Alliant Energy. Alliant Energy - Columbia Energy Storage Project