Energy Dome starts Sardinia plant with 200 megawatt-hours of storage

Energy Dome’s first commercial plant in Sardinia, Italy, has a capacity of 200 megawatt-hours and began operating in 2025. The system stores energy through a cycle involving compressed carbon dioxide, stored heat and a turbine. The company’s technology is designed to provide electricity for up to 24 hours when the grid needs it.

The facility’s stated capacity and operating date mark a commercial step for a technology intended for longer-duration energy storage. Energy Dome says its approach can hold electricity generated when it is available and release power later. The source describes one commercial project as operational, placing the Sardinia plant at the centre of the company’s current deployment record.

Sardinia plant begins commercial operation

The plant is located in Sardinia, Italy, and Energy Dome turned it on in 2025. Its capacity is 200 megawatt-hours, a measure of the amount of energy it can store and deliver. The source says that output could power about 18,000 Italian homes for 10 hours. That comparison gives a household scale for the facility, while the stated capacity remains the plant’s principal technical measure.

Energy Dome’s system uses a large dome to hold about 2,000 metric tons of carbon dioxide. When energy is available, compressors pressurise the gas and turn it into liquid. The liquid moves into carbon-steel tanks, while heat produced during compression is retained in a thermal storage material. Together, those steps prepare the stored material and heat for a later discharge cycle.

Compressed gas drives the storage cycle

When electricity is needed, the carbon dioxide leaves the tanks and is warmed with the stored heat. It returns to a gaseous state and passes through a turbine, which generates electricity. The gas then flows back into the dome, ready for the process to begin again. This sequence explains how the plant stores energy and returns it to the grid without relying on a particular underground formation.

The source says compressed-air storage has been used by utilities in underground caverns for decades. Energy Dome’s design does not require specific geology, according to the account, which could make siting more flexible. The equipment described includes compressors and storage tanks that are already commercially available. Energy Dome says this use of existing equipment supports scaling its plants, though the account does not provide a construction timetable for further facilities.

Project plans extend beyond Sardinia

Energy Dome was founded in 2020 and is headquartered in Milan, Italy, according to the supplied company details. The source says the company has plans for 30 gigawatt-hours’ worth of projects across five continents. Plans indicate a development pipeline, while the same account identifies only one commercial project as operational. The supplied material does not name locations or dates for the other projects.

The company estimates its technology is roughly 10 percent to 15 percent cheaper than lithium-ion batteries for an eight-hour system. It says the economics improve for longer-duration systems, with the technology able to deliver power for up to 24 hours. Those are company estimates and statements, rather than independently verified cost findings in the supplied account. The plant’s confirmed capacity and operation in Sardinia therefore remain distinct from the broader claims about future costs and deployment.

Further deployments remain uncertain

The source describes the Sardinia facility as Energy Dome’s sole operational commercial project. It does not provide a schedule for the other planned projects or confirm how many will reach operation. The cited plans cover 30 gigawatt-hours across five continents, but the material gives no site-by-site breakdown. Those missing details limit what can be established about the pace of expansion.

Energy Dome’s account of cost and scalability is presented as the company’s own assessment. No response from the company to questions about those estimates or the wider project plans appears in the supplied material. Further reporting would need to establish which planned facilities have contracts, where they will be built and when they may begin operating. The next concrete milestone will be whether another commercial plant enters operation beyond Sardinia.