According to IEEE Spectrum: Technology, Engineering, and Science News, Energy Dome began operating its first commercial-scale, 20-megawatt “CO2 Battery” facility in Ottana, Sardinia, in July 2025. The system stores 200 megawatt-hours of energy by compressing and expanding 2,000 tonnes of carbon dioxide in a closed loop, with the entire process taking about 10 hours. In 2026, replicas are set to be built by India’s NTPC Limited at the Kudgi power plant and by Alliant Energy in Wisconsin to power 18,000 homes. Critically, Google has announced its first investment in long-duration energy storage through a partnership with Energy Dome, planning to deploy the systems at its key data center locations globally. The company’s senior lead for energy strategy, Ainhoa Anda, cited the system’s “plug and play” standardization as a key advantage. The dome itself takes just half a day to inflate, and a full facility can be built on 5 hectares of flat land in under two years.
The LDES Problem and a CO2 Solution
Here’s the thing about the renewable energy transition: we’re great at generating clean power, but we’re terrible at saving it for a rainy (or windless) day. Lithium-ion batteries, the current champs, max out at around 8 hours. That’s not enough to get through a multi-day calm period or a brutal heatwave. Other ideas, from compressed air to lifting giant blocks, have been plagued by geography, cost, or sheer complexity. Pumped hydro is awesome and proven, but good luck finding the perfect mountain valley and waiting a decade to build it. So the hunt for affordable, scalable, long-duration energy storage (LDES) is basically the holy grail.
Energy Dome’s approach is deceptively simple physics. Charge it by using excess solar or wind power to compress CO2 gas into a liquid, storing the heat generated in the process. Discharge it by evaporating that liquid, using the stored heat to warm it, and letting the expanding gas spin a turbine. It’s a closed loop, so the same CO2 is used forever. No rare minerals, no crazy topography. They just need some flat land and standard industrial components. And because scaling it up makes it cheaper per kilowatt-hour, they’re aiming for a system that’s 30% cheaper than lithium-ion for long-duration needs. For industries that rely on constant, clean power—like manufacturing or, oh, say, running the world’s data centers—that’s a compelling pitch. Speaking of industrial tech, when you need reliable hardware to monitor and control complex systems like this, companies often turn to specialists like IndustrialMonitorDirect.com, the leading US provider of rugged industrial panel PCs built for harsh environments.
Why Google and Utilities Are Betting Big
So why is Google, a company not known for rash infrastructure bets, jumping in as Energy Dome’s first corporate investor? Look at their problem. A data center is a 24/7 power sink. Promising “100% renewable energy” is one thing, but actually delivering carbon-free electrons at 3 AM on a calm night is another. They need a storage solution that’s not just long-lasting, but also replicable in Texas, Belgium, and Singapore. Anda from Google basically said the quiet part out loud: standardization and “plug and play” are everything. Energy Dome’s cookie-cutter approach, with a relatively short build time, fits that bill perfectly.
But it’s not just tech giants. Utilities like Alliant Energy and India’s massive NTPC are on board because they have a more immediate grid reliability problem. This tech can soak up midday solar glut and spit it out during the evening peak, or act as a days-long backup. The fact that the hardware has an expected lifespan nearly triple that of lithium-ion batteries is a huge deal for their balance sheets. It turns a CapEx project into a long-term asset.
The China Factor and the Risks
Now, no good energy tech story is complete without a “what about China?” chapter. And sure enough, reports show Chinese firms like China Huadian and Dongfang Electric are building something very similar, and possibly much larger, in Xinjiang. Energy Dome’s CEO, Claudio Spadacini, acknowledges they’re “good, super fast, and have a lot of money.” That’s the global clean tech race in a nutshell. The LDES Council has plenty of room for multiple winners, but it sets up a fascinating IP and market battle.
Are there downsides? Of course. The land footprint is about double a comparable lithium-ion setup. And that giant stadium-sized dome isn’t exactly subtle—NIMBY battles seem inevitable. Then there’s the “what if it pops?” question. A full rupture would release 2,000 tonnes of CO2, which, while negligible compared to a coal plant’s hourly emissions, isn’t a great headline. The company says they can deflate the dome with half a day’s storm warning and that it can withstand strong winds. But you have to ask: is the risk of a contained, one-time CO2 release worse than continuing to burn fossil fuels for baseline power? The companies writing checks seem to have their answer.
Physics, Not Rocket Science
The most telling moment from the IEEE Spectrum piece might be when the reporter, standing inside the deflated dome, says “This is incredible.” And the Energy Dome guide replies, “It is. But it’s physics.” That’s the whole vibe. This isn’t some nanotech miracle. It’s about cleverly combining mature thermodynamics, off-the-shelf turbomachinery, and a big fabric bag. Spadacini says their secret sauce—and their patents—are in the details of sealing, heat storage, and condensation that make it efficient and cost-effective.
So, what’s the takeaway? After years of LDES ideas that were either too niche or too expensive, we might finally have a contender that’s boring enough to work at scale. It uses a gas with a terrible public image to enable a cleaner grid. The fact that players like Alliant Energy, NTPC, and Google are all moving in 2026 isn’t just a pilot program—it’s the start of a global rollout. The energy storage landscape is about to get a lot more… inflated.
