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World’s first CO2 thermal energy storage battery to be built in Italy


Artist impression of the Energy Dome and solar farm Photo: Energy Dome
Artist’s impression of Energy Dome’s CO2 thermal energy storage battery

Photo: Energy Dome

Innovative long duration energy storage company Energy Dome plans to build its first CO2-based thermo-mechanical energy storage plant in Sardinia, Italy, later this year.

The Milan-based start-up, which was recently named ‘European & Israel company of the year’ in the Cleantech100 awards for development of a viable alternative for long duration energy storage, unveiled plans to build the energy dome at Ottana, during COP28 in Dubai. The 20 MW/200 MWh CO2 battery, to be built in 3Q2024, will supply energy to the grid for 10 consecutive hours and ‘could easily be duplicated to accelerate the energy transition’, says the company.


The CO2 battery uses readily available, off-the-shelf components to provide a scalable pathway to store massive amounts of intermittent renewable energy. As a closed thermo-mechanical transformation unit, the system converts CO2 between its gaseous and liquid phase. As the CO2 warms up, it evaporates and expands, turning a turbine to generate electricity, with zero emissions to the atmosphere.


Project funding is being provided in the form of a project level grant commitment of up to €35mn from Bill Gates’s Breakthrough Energy Catalyst and €25mn venture debt financing from the European Investment Bank.  


The CO2 battery is claimed to address the issue of utility-scale long duration energy storage with a ‘significantly more cost competitive solution than the lithium-ion benchmark for energy storage’, says Energy Dome Founder and CEO Claudio Spadacini. ‘The collaboration with the EU-Breakthrough Energy Catalyst partnership is a true catalyst for our company and will accelerate the commercialisation of our market-ready technology, which [he hopes] will be the first of many identical full-scale CO2 batteries.’


Since the CO2 battery doesn’t operate at cryogenic temperatures there are none of the high costs typically associated with compressed air storage, explains Spadacini. ‘There is massive reduction of costs by storing the CO2 at ambient temperature in its liquid phase,’ he claims.


For a round-up of other alternative thermal energy battery systems see this week’s ‘Hot rocks’ feature article.