As global energy systems transition toward higher shares of renewable generation, the need for reliable, long-duration energy storage has become increasingly critical. Addressing this challenge, Energy Dome has developed an innovative CO2 Battery, a grid-scale storage solution designed to deliver dispatchable, emission-free power over extended durations.
The CO2 Battery is based on a closed Brayton-like cycle in which CO2 is continuously recirculated within a sealed system. During the charging phase, surplus renewable electricity powers a multi-stage compression process that increases the pressure of CO2 gas while simultaneously generating heat. This thermal energy is captured and stored in an integrated thermal energy storage (TES) subsystem, while the compressed CO2 is condensed into a liquid state and stored at near-ambient temperature within a high-density containment structure. This dual storage of thermal and pressure energy enables the system to retain energy with minimal losses over time.
When electricity demand rises, the system reverses the process. The stored liquid CO2 is pressurized, evaporated, and reheated using the previously stored thermal energy before being expanded through a turbine. This expansion drives a generator to produce electricity, after which the CO2 returns to its gaseous state and is recirculated within the system. By internally reusing stored heat, the CO2 Battery eliminates the need for external thermal input during discharge, achieving a round-trip efficiency in the range of approximately 75–80%.
A key technical advantage of the system lies in its ability to store CO2 in liquid form at ambient temperatures, avoiding the need for cryogenic conditions typically associated with alternative long-duration storage technologies such as liquid air energy storage. This significantly reduces system complexity, energy losses, and operational costs. Furthermore, the use of mature industrial components—including compressors, heat exchangers, and turbomachinery—enhances reliability while mitigating supply chain constraints associated with critical raw materials such as lithium and cobalt.
Designed for modular and scalable deployment, the CO2 Battery supports discharge durations ranging from 8 to 24 hours or more, making it well-suited for balancing intermittent renewable generation, shifting peak loads, and providing grid stability services. The turbine-based generation architecture also enables inherent inertia and grid-forming capabilities, offering advantages over inverter-dominated battery systems in maintaining frequency and voltage stability in high-renewable grids.
By combining thermodynamic efficiency, mechanical durability, and material sustainability, Energy Dome’s CO2 Battery represents a compelling alternative to conventional energy storage technologies. As utilities and grid operators seek solutions capable of delivering long-duration, dispatchable power, the company’s approach positions it as a key contributor to the development of resilient and low-carbon energy systems.
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About Energy Dome
Energy Dome is an Italy-based energy technology company focused on the development of long-duration energy storage solutions for utility-scale applications. The company has pioneered the CO2 Battery, a patented system that utilizes carbon dioxide in a closed-loop thermodynamic process to enable cost-effective, scalable, and sustainable energy storage.
