Energy Dome’s first commercial plant in Sardinia, Italy, has 200 megawatt-hours of capacity and can store energy for up to 24 hours. The facility began operating in 2025, applying compressed carbon dioxide to long-duration grid storage. The approach is intended to hold electricity when it is available and generate it again when the grid needs power.
How did the storage process begin?
Energy Dome’s system starts when electricity is available, for example from a connected solar farm. Compressors use that energy to turn carbon dioxide gas into a liquid. The liquid is held in carbon-steel tanks while heat from compression is retained in a proprietary thermal storage material.
When electricity is needed, the stored carbon dioxide leaves the tanks and is warmed using the retained heat. It returns to a gaseous state and passes through a turbine, generating electricity. The gas then flows back into the dome, ready for the cycle to begin again.
What has Energy Dome put into operation?
The company turned on its first commercial facility in Sardinia, Italy, in 2025. Its capacity is 200 megawatt-hours, and the system can deliver power for up to 24 hours. The facility’s capacity is reported as sufficient to power about 18,000 Italian homes for 10 hours.
Energy Dome was founded in 2020 and has its headquarters in Milan, Italy. The company has plans for projects with 30 gigawatt-hours of capacity across five continents. Those plans describe a pipeline, while the Sardinia plant is the company’s first commercial project reported as operational.
What remains unresolved about its scale?
Energy Dome has only one commercial project operating, according to the source material. Its plants that are operational or under contract have eight or 10 hours of capacity. The account does not identify further operational sites or give a timetable for delivering the wider project plans.
The source also says that long-duration storage economics differ from short-duration applications. It reports that Energy Dome estimates its technology is roughly 10% to 15% cheaper than lithium-ion batteries for an eight-hour system, with better economics for longer durations up to 24 hours. These are company estimates, and no independent assessment is included in the material.
The available information does not state the Sardinia facility’s cost or disclose performance results beyond its capacity and duration. It also leaves open how quickly the company can build projects beyond its first commercial plant. Follow-up reporting can track new operational facilities, disclosed results and any changes to the planned 30 gigawatt-hours pipeline.
Sources
- Energy Dome and its carbon dioxide batteries technologyreview.com