‘CO2 battery’ technology getting megawatt-scale demonstrator in Italy

By Andy Colthorpe
LinkedIn
Twitter
Reddit
Facebook
Email
Rendering by Energy Dome with CO2 battery system on right hand side. Image: Energy Dome.

A 2.5MW / 4MWh demonstration system using novel energy storage technology based on a “carbon dioxide battery” has begun construction in Sardinia, Italy.

The CO2 battery technology has been developed by Energy Dome, a Milan-headquartered company founded by technologist and entrepreneur Claudio Spadacini and incorporated two years ago. The battery can offer long durations of storage between three to 16+ hours, can be built using off-the-shelf components used in other industries and uses a closed loop thermodynamic process which can enable a high round-trip efficiency, the company claims. It also suffers “little or no degradation” over an anticipated lifetime of more than 25 years.

The battery charges by drawing CO2 from a dome where it is kept, condensing it into a liquid at ambient temperature, while heat created by the compression process is stored in thermal energy storage systems. It then discharges by evaporating and expanding the CO2 back into a gas by heating it using the thermal storage systems. The gas is driven through a turbine to inject power into the grid and then pushed back into the dome, ready to be used for the next charging cycle.

Energy Dome said the demonstration plant will be used to prove the technology’s efficiency, as well as its capability to provide energy and regulation services for the grid. The main technical risks it faces are to do with component integration, according to the company, but if successful the project can be expanded initially to 8MWh or more.

This article requires Premium SubscriptionBasic (FREE) Subscription

Try Premium for just $1

  • Full premium access for the first month at only $1
  • Converts to an annual rate after 30 days unless cancelled
  • Cancel anytime during the trial period

Premium Benefits

  • Expert industry analysis and interviews
  • Digital access to PV Tech Power journal
  • Exclusive event discounts

Or get the full Premium subscription right away

Or continue reading this article for free

Meanwhile, the demonstrator will be built using the same components that would be used in a much bigger configuration, with Energy Dome suggesting that 25MW / 100MWh or 200MWh plants could later be built once the tech is shown to be ready for market.

On its website, the company compares the technology as being potentially lower cost than compressed air energy storage (CAES) or liquid air energy storage (LAES), which might be considered competing energy storage technologies. This is because unlike CAES which requires very large underground sealed vessels such as salt caverns to store a large volume of air, or LAES which requires equipment to cool air until it liquifies, the liquid phase CO2 can be stored at ambient temperature, the company said.

Energy Dome also said in a press release this week that its solution could also overcome the limitations of lithium-ion, posing no fire risk, manufacturable without rare earth materials and also even has better performance and lower capital cost. The demonstrator in Sardinia is expected to be launched early next year.

3 November 2026
Málaga, Spain
Understanding technology and supplier selection for Europe’s utility-scale PV market in 2027. PV ModuleTech Europe 2026 is a two-day conference that tackles these challenges directly, with an agenda that addresses all aspects of PV module, inverter and battery supplier selection; product availability, technology offerings, supply chain traceability, quality assurance, factory auditing, system reliability, and supplier bankability.

Read Next

September 11, 2026
Our collection of user-posted analysis, views, and unofficial news, gathered from our networks on LinkedIn, returns for its third outing.
September 7, 2026
Pakistan’s National Electric Power Regulatory Authority (NEPRA) has approved plans to require bidders in a renewable energy auction to include energy storage.
September 7, 2026
Blueleaf Energy and Universal Peak have closed financing for a 100MW/400MWh battery storage project, which was one of four winning bids in a Malaysian government tender.
September 3, 2026
Bulgaria now has a world-leading amount of battery storage capacity relative to energy system despite a period of political turnover, although those assets are now cannibalising the revenues which attracted investment in the first place.
September 3, 2026
The European Commission’s late approval of Germany’s capacity market auctions leaves no room for public scrutiny, according to environmental law charity ClientEarth.