Company Profile · Long-Duration Storage Energy Dome’s next product is repeatability The Milan-based developer has put a full-scale CO₂ Battery on the grid. Turning that reference plant into a repeatable infrastructure business is the harder test. By CurrentCells Staff · October 6, 2026 AI-generated editorial illustration of a conceptual CO₂ storage facility; not a photograph or engineering rendering of an Energy Dome project. Energy Dome is not trying to make a better lithium-ion cell. It is trying to build a different kind of power plant: one that consumes electricity when it is available, stores that energy through a closed carbon-dioxide cycle, and returns electricity through a turbine when the grid needs it. Its opportunity sits between short-duration battery dispatch and the much harder problem of supplying dependable clean power through long gaps in renewable generation. The company is based in Milan and led by founder and chief executive Claudio Spadacini. Its signature product, the CO₂ Battery, combines an unmistakable membrane dome with compressors, heat storage, pressure vessels and turbine equipment. The engineering proposition is industrial rather than electrochemical. Instead of betting on a new electrode material, Energy Dome is assembling established equipment into a proprietary storage system. That distinction makes it relevant to the battery industry even though its product contains no lithium-ion cells. Developers, utilities and large electricity buyers ultimately purchase dispatchable capacity, energy and operating reliability. A technology that can serve those needs over longer daily discharge periods competes for some of the same project budgets as batteries, while potentially complementing them at other sites. Company snapshot: evidence, not pipeline arithmetic Core business: long-duration electricity storage using a closed-loop carbon-dioxide thermodynamic cycle. Commercial reference: the 20 MW/200 MWh Ottana plant in Sardinia, reported by IEEE Spectrum as beginning operation in July 2025. Major commercial backer: Google, which announced an investment and a global commercial partnership in July 2025. The announcement does not disclose the investment amount. New-build milestone: a 23 MW/200 MWh Irish project contracted with Google, with operation expected in 2028 rather than already achieved. The separation between these categories is important. An operating reference plant, a corporate investment, a signed commercial agreement and a future project are different kinds of evidence. Together they support a credible scaling story; they do not mean the entire announced pipeline is built, financed or earning revenue. How the CO₂ Battery works During charging, electricity drives compression of carbon dioxide drawn from the dome. Heat is captured within the system, and the gas is condensed into liquid for storage in pressure vessels. During discharge, the stored carbon dioxide is evaporated, heated and expanded through a turbine connected to a generator. The gas returns to the dome to begin another cycle. The dome is therefore part of the working-fluid circuit, not simply a warehouse built around conventional battery racks. This is not carbon capture or a carbon-removal credit scheme. IEEE Spectrum reports that the Sardinia installation uses purpose-supplied carbon dioxide, retained inside the system in normal operation. Its climate value comes from the electricity system it serves: shifting low-carbon power to hours when it can displace higher-emitting generation. Charging from a carbon-intensive grid would change that calculation. Calling the working fluid “carbon dioxide” does not by itself establish either a climate benefit or a climate penalty. Google describes the technology’s intended discharge range as eight to 24 hours. That is a product-family description, not proof that every installation delivers the same duration. The Sardinia reference plant’s 200 MWh divided by its 20 MW rating gives ten hours at rated output. The announced Irish project’s 200 MWh divided by 23 MW gives about 8.7 hours. Those simple ratios help prevent a common storage mistake: confusing megawatts of instantaneous power with megawatt-hours of stored energy. Using familiar compressors, vessels and turbines can reduce exposure to cell-material supply chains. It does not eliminate supply-chain risk. Turbomachinery procurement, pressure-system fabrication, construction quality, controls integration and maintenance still determine whether equipment arrives on time and performs as contracted. Energy Dome is substituting one industrial delivery challenge for another, not escaping industrial execution altogether. Why Sardinia matters more than a rendering The Ottana facility gives Energy Dome something that many storage startups struggle to obtain: a full-scale grid-connected reference. IEEE Spectrum’s reporting describes a 20 MW/200 MWh installation operating from July 2025 and explains the physical charging and discharging cycle after a site visit. Google’s partnership announcement also cites the full-scale Italian plant and the earlier demonstration facility as evidence supporting its decision. That evidence changes the question from whether the basic architecture can be assembled to whether it can be replicated economically. One reference plant cannot establish lifetime maintenance costs, long-run availability or the performance of a fleet across multiple climates and electricity markets. Prospective buyers still need contractual guarantees, acceptance tests, insurance, service arrangements and evidence that the project’s economics survive realistic operating assumptions. Energy Dome’s scaling advantage could come from standardization. A repeatable plant design can simplify procurement and give lenders a recognizable technical package. But civil works, local codes, connection requirements and revenue contracts remain site-specific. The business becomes more valuable if the standard design survives those local variations without turning every sale into a bespoke engineering exercise. Google is a commercialization partner, not a blanket guarantee Google’s July 2025 announcement pairs a company investment with support for multiple commercial deployments. Its motivation is straightforward: annual renewable-energy purchases are not the same as matching consumption with carbon-free electricity every hour. Longer-duration storage can help bridge that temporal gap. Google said it expected the collaboration to unlock additional clean energy on relevant grids before 2030. The Irish agreement makes the relationship more concrete. In July 2026, pv magazine reported a 23 MW/200 MWh project in County Offaly, near the Rhode Green Energy Park, to be owned and operated by Energy Dome. The report says land, planning consent and a grid connection had been secured, alongside a ten-year EirGrid capacity contract. Commercial operation is expected in 2028. A second 200 MWh unit at the location is a development plan, not an operating asset. Ownership matters to the company profile. Supplying technology produces a different balance-sheet and risk profile from building, owning and operating an electricity-storage facility. An owner-operator can capture recurring value over a project’s life, but must also arrange project funding and carry construction and operating obligations. Google’s involvement is a meaningful commercial signal; it does not make every future project automatically bankable or remove the need for due diligence. Where it competes—and where it does not The most useful comparison is not a universal claim that carbon-dioxide storage beats lithium-ion. It is a project-specific comparison of duration, efficiency, installed cost, land, availability, financing and the value of delivered electricity. Lithium-ion benefits from a large installed fleet and a mature supplier ecosystem. Energy Dome is targeting situations where longer discharge periods and a different equipment