Energy Dome has developed a CO2 battery system that is already operational in Europe and now available for purchase. This technology promises 24-hour energy storage with a lifespan exceeding 30 years and claims zero capacity degradation over its lifetime. The system uses a closed-loop process involving liquid and gaseous CO2, offering a new approach to grid-scale energy storage without relying on lithium or rare earth materials. Although pricing remains undisclosed, the company says the system can be delivered turnkey and operational within 15 months.
How the CO2 Battery Works
The core of Energy Dome’s technology is a patented thermomechanical cycle that manipulates CO2 between its liquid and gaseous phases. During periods of excess energy, CO2 is drawn from a dome-shaped gas holder, compressed into a liquid, and stored in high-density vessels at ambient temperature. The heat generated during this compression is captured and stored in a dedicated thermal energy storage system.
When the grid needs power, the stored liquid CO2 is heated using the stored thermal energy, evaporated, and sent through a turbine to generate electricity. The CO2 then returns to the atmospheric gas holder, completing a closed loop with zero atmospheric emissions.
Efficiency and Lifespan Compared to Lithium Batteries
The round-trip efficiency of the CO2 battery is about 75%, which is lower than the 92 to 94% efficiency typical of lithium-ion batteries. However, it outperforms other similar large-scale storage solutions, such as compressed air batteries. A key advantage is its longevity: Energy Dome claims more than 30 years of operation with no capacity degradation, a significant improvement over conventional batteries that typically lose capacity after 25 to 30 years.
Integration With Gas Turbines and Industrial Waste Heat
The system can operate independently or in conjunction with open-cycle gas turbines. In the “plus” configuration, the CO2 battery replaces stored heat with direct waste heat from a co-located gas turbine’s exhaust. This not only amplifies the discharge phase, allowing for double peak power output, but also boosts the efficiency of gas-fired power generation.
There are three main operating modes:
- Charge mode: Compresses and stores liquid CO2 during low demand periods.
- Discharge (Super Boost) mode: Uses turbine exhaust heat to evaporate liquid CO2, driving the turbine for double peak power output.
- Generation mode: Runs the compressor and turbine simultaneously in a closed loop, increasing net power output by up to 25% with no extra fuel.
By replacing stored heat with industrial waste heat, the system can achieve a claimed 115% round-trip efficiency, making it particularly attractive for data centers and industries looking to lower delivered energy costs and reduce their carbon footprint.
Market Impact and Industry Claims
Energy Dome claims to have a global project pipeline of 30 gigawatt hours, which is surprising for a technology that has received relatively little attention. The system is modular, plug-and-play, and can be operational within 15 months of order. While I can’t verify the scale of their pipeline, the technology offers a new option for long-duration storage without the resource constraints of lithium batteries.
What This Means for Energy Storage
I think the CO2 battery is an intriguing alternative for grid-scale energy storage, especially where long-duration storage and minimal capacity degradation are priorities. Its integration with gas turbines could help make existing fossil fuel infrastructure more efficient, though it doesn’t make gas generation environmentally positive. The lower efficiency compared to lithium batteries is a trade-off, but the system’s longevity and ability to use waste heat could make it a valuable tool for utilities and industries managing variable loads and seeking to reduce emissions.
