CO₂ Battery: Closed Thermo-Mechanical Energy Storage Explained

Q: What is a CO₂ battery and how does it work?

A CO₂ battery (developed by Energy Dome) is a closed thermodynamic system that stores energy by liquefying carbon dioxide when electricity is cheap, then re-gasifying it through a turbine to generate electricity when needed. No CO₂ is released: the gas cycles continuously inside the sealed system.

Q: What is the round-trip efficiency of the CO₂ battery?

The CO₂ battery achieves approximately 75% round-trip efficiency, meaning 75% of the electricity used to charge it is recovered during discharge. This is comparable to lithium-ion batteries and significantly better than many alternative long-duration storage technologies.

Q: How long can a CO₂ battery store energy?

The CO₂ battery is designed for long-duration energy storage, capable of storing and discharging energy over periods of 8 to 24 hours, making it suitable for grid balancing applications that lithium-ion batteries cannot economically serve.

Q: Is the CO₂ battery an alternative to lithium-ion batteries?

Yes, for grid-scale long-duration storage. The CO₂ battery avoids lithium, cobalt, and rare earth mining, uses widely available CO₂ as the working fluid, has a 30+ year operational lifespan, and can be built with standard industrial components, making it a more sustainable and scalable alternative for utility storage.

Learn how the CO₂ Battery stores and generates electricity using closed thermo-mechanical cycles with carbon dioxide: offering long-duration energy storage with zero emissions.

📅 8 September 2025

The CO₂ Battery is a breakthrough closed thermo-mechanical energy storage system developed by Energy Dome. It stores electricity by cycling carbon dioxide between high-pressure liquid and gaseous phases, then converts expansion into electricity without emissions, cryogenics, or rare materials.

🔄 How It Works (Charge & Discharge)

Charging: CO₂ is compressed into liquid form and stored in a dome-style gasholder at ambient temperature.
Discharging: Liquid CO₂ evaporates and expands, driving a turbine to generate electricity, then returns to the dome.

⏳ Storage Characteristics

Designed for long-duration energy storage, the CO₂ Battery performs best between 8–24 hours, ideal for renewable integration, peak shaving, and grid stabilization.

🌱 Carbon-Neutral & Cost-Efficient

During operation, no CO₂ is released into the atmosphere. Unlike compressed air storage or lithium-ion batteries, it works at ambient temperature, avoiding cryogenic cooling and critical minerals. It uses only water, steel, and CO₂, readily available from Tier-1 suppliers.

🏆 CO₂ Vs. Lithium-Ion Batteries

Feature	CO₂ Battery	Lithium-Ion
Round-trip efficiency	~75% (no degradation)	~85% (degrades over time)
Lifetime	30+ years	<12 years
CAPEX	1× (baseline)	~1.7× higher
Depth of discharge	100%	<80%
Components	Standard, globally available	Depends on critical minerals
Installation time	< 2 years	< 2 years

🔧 Scalable & Grid-Compatible

Built from standard industrial components, the CO₂ Battery is modular, scalable, and deployable worldwide. It supports grid services such as:

⏱ Time-shifting renewable energy
⚡ Frequency containment & restoration reserves (FCR, aFRR, mFRR)
🔌 Millisecond-level voltage regulation

Discover how the CO₂ Battery from Energy Dome is pioneering the future of long-duration energy storage and accelerating the energy transition.

Frequently Asked Questions

What is a CO₂ battery and how does it work?

A CO₂ battery (developed by Energy Dome) is a closed thermodynamic system that stores energy by liquefying carbon dioxide when electricity is cheap, then re-gasifying it through a turbine to generate electricity when needed. No CO₂ is released: the gas cycles continuously inside the sealed system.

What is the round-trip efficiency of the CO₂ battery?