Google is moving beyond traditional lithium-ion packs and into industrial-scale carbon dioxide storage, backing giant “CO2 batteries” that can hold roughly 200 MWh of energy in a single installation. Instead of stacking containers of cells, the company is betting on inflatable domes, compressors and turbines to keep its data centers running on clean power even when the wind drops and the sun goes down. The result is a new kind of long-duration storage asset that looks more like a chemical plant than a battery, but is designed to deliver grid-scale electricity on demand.
At the center of this push is a partnership with Italian startup Energy Dome, whose technology uses carbon dioxide as a working fluid that can be compressed, liquefied and expanded to store and release electricity. By rolling out multiple 200 MWh class units, Google is trying to solve one of the hardest problems in the energy transition: how to match variable renewables with the relentless appetite of artificial intelligence and cloud computing.
Why Google is betting on long-duration storage now
Google’s cloud and AI operations are turning into some of the most power-hungry infrastructure on the planet, and the company has publicly committed to running on clean electricity around the clock rather than just matching annual consumption with renewable certificates. To move from marketing slogan to engineering reality, it needs storage that can bridge multi-hour gaps between when solar and wind generate power and when its data centers actually need it, a challenge that short-duration lithium systems alone cannot solve. That is why Google has framed its work with Energy Dome as its first major step into long-duration energy storage, positioning these CO2 systems as a backbone for 24/7 carbon-free operations.
In its own description of the program, Google explains that it is partnering with Energy Dome to pilot a new class of storage that can shift large blocks of renewable generation across the day and even across seasons, complementing existing batteries and earlier-stage investments in other technologies such as geothermal and hydrogen. The company notes that this long-duration portfolio is intended to support its goal of delivering carbon-free energy “every hour of every day” before 2030, a target that requires far more than rooftop solar and grid purchases, and it presents the collaboration as part of a broader strategy to scale up long-term energy storage across its global footprint.
Inside the alliance with Energy Dome
Google’s relationship with Energy Dome is not a casual pilot but a structured alliance that ties the tech giant’s clean energy ambitions to a specific hardware roadmap. The company has described this as a long-term collaboration that will see Energy Dome’s CO2 Battery technology deployed near major data centers, with Google effectively acting as both anchor customer and strategic partner. I see this as a classic example of a large buyer using its balance sheet and power demand to pull an emerging technology out of the lab and into commercial reality.
The alliance is framed around the idea that long-duration storage must be available at scale before the end of this decade if Google is to meet its 24/7 carbon-free energy target, and the company has explicitly linked its work with Energy Dome to that 2030 timeline. In public materials, Google highlights how this partnership is intended to accelerate deployment of CO2-based storage plants that can run for many hours at full output, describing the arrangement as an “alliance” with Google and Energy Dome working together to scale long-duration storage so that clean power is available every hour of every day before 2030.
How a CO2 battery actually works
At first glance, a CO2 battery looks nothing like the lithium packs inside an electric car, and that is the point. Energy Dome’s design centers on a large, sealed facility where a big dome holds carbon dioxide gas, which can be drawn down, compressed and liquefied when there is surplus renewable electricity on the grid. During charging, the system uses that excess power to run compressors that pull CO2 from the dome and store it under pressure, effectively banking energy in the form of high-pressure, liquefied gas that can sit ready until demand spikes.
When the grid needs power, the process reverses. The stored CO2 is evaporated and heated, then expanded through a turbine to generate electricity, after which the gas returns to the dome to start the cycle again. This approach relies on well-understood thermodynamic principles and off-the-shelf industrial components rather than exotic materials, which is one reason Google has been willing to back it at scale. Technical descriptions of the system emphasize that the solution consists of a large dome of CO2 connected to compressors, heat exchangers and a turbine, and that Energy Dome has already demonstrated a 20 MW, 200 MWh commercial plant in Italy using this state-shifting CO2 storage medium.
From Sardinia prototype to 200 MWh giants
The blueprint for Google’s new installations traces back to The Sardinia plant, a full-scale demonstration facility that shows how a CO2 battery behaves on a real grid. That site generates 20 megawatts of power and stores 200 megawatt-hours of energy, meaning it can run at full output for roughly ten hours, a duration that puts it firmly in the long-duration category. In my view, that combination of 20 MW of capacity and 200 MWh of storage is what makes the technology relevant for data centers, which need multi-hour coverage rather than just short bursts.
Reporting on the Sardinian project describes how the island installation has become a template for larger deployments, with its 200 m scale providing a reference point for future plants that could be replicated in other regions. The same accounts explain that the facility is part of a broader narrative described as “From One Island to a Global Grid,” in which The Sardinia project is seen as a stepping stone toward a worldwide network of CO2-based storage assets that use carbon dioxide as a working fluid for a cleaner future, and they highlight that the plant’s 20 MW and 200 MWh metrics are central to that From One Island vision of a Global Grid.
Why Google chose CO2 over more lithium
Google’s decision to back CO2 batteries instead of simply ordering more lithium-ion containers reflects both engineering pragmatism and supply chain caution. Lithium systems are excellent for fast response and short durations, but their economics and degradation profiles become less attractive when stretched to eight or ten hours, especially at the scale of a hyperscale data center. By contrast, Energy Dome’s CO2 Battery uses abundant carbon dioxide, steel tanks and mechanical equipment, which can be cheaper to scale and less exposed to the price swings that have hit lithium, nickel and cobalt.
Google has said it selected Energy Dome’s CO2 Battery because it provides clean, dispatchable energy using mechanical components and simple physics, rather than relying on rare materials or complex chemistries that are harder to recycle. The company also points to the technology’s ability to deliver multi-hour output without direct emissions, since the CO2 is kept in a closed loop rather than vented to the atmosphere. That combination of dispatchability, material simplicity and climate performance is cited as the reason Why Google opted for this Battery design from Energy Dome instead of doubling down on conventional lithium packs.
Wisconsin’s first CO2 battery and the US buildout
The United States is emerging as a key proving ground for these giant CO2 batteries, and Wisconsin is at the front of that curve. State regulators there have approved Wisconsin’s First CO₂ Battery Project Gains Approval, clearing the way for Energy Dome to build a commercial-scale plant that will connect to the local grid and demonstrate how the technology performs in a Midwestern climate. For Google, which operates data centers in the region, that project offers a concrete example of how CO2 storage can be integrated into existing utility infrastructure rather than confined to experimental sites.
Details of the Wisconsin initiative show that it is part of a broader pipeline of long-duration energy storage sites that Energy Dome is planning across North America, with Google’s investment helping to de-risk early deployments. The company’s involvement is framed as both financial and strategic, with Google providing capital and a long-term offtake signal that supports future LDES sites beyond the first Wisconsin plant. Coverage of the project notes that Wisconsin’s First CO Battery Project Gains Approval is a milestone in that expansion, and that Google and Energy Dome see it as a template for additional long-duration storage hubs.
The 200 MWh US carbon battery and grid integration
Beyond Wisconsin, Energy Dome is also developing a 200 MWh carbon battery in the United States that aligns closely with the scale of The Sardinia plant. The system charges by drawing CO2 from a gasholder dome and storing it under pressure, a process that can be repeated daily as solar and wind output fluctuate. Alliant Energy says the Columbia site that will host this installation is expected to deliver 200 MWh of storage capacity and be completed in 2026, positioning it as one of the first full-scale CO2 batteries on the US grid.
For grid operators, the appeal of such a plant is its ability to absorb excess renewable generation during off-peak hours and then discharge during evening peaks, smoothing out the mismatch between production and demand. The Columbia project is described as a key part of Alliant’s strategy to integrate more wind and solar while maintaining reliability, and it is also a tangible example of how Google’s preferred storage technology can serve not just data centers but entire regions. Technical summaries of the project emphasize that Energy Dome will deliver a 200 MWh carbon battery at the Columbia site and that the installation is expected to be completed in 2026.
From pilot to rapid deployment
What began as a single demonstration dome is now turning into a fleet strategy, with Google rapidly deploying huge CO2 battery facilities that can support its global network of data centers. The company’s own framing of the rollout emphasizes speed and replication, suggesting that once the core design is validated, additional plants can be built using a modular approach that reuses the same compressors, turbines and control systems. In my assessment, that shift from bespoke engineering to repeatable product is what will determine whether CO2 batteries become a niche curiosity or a mainstream part of the grid.
Descriptions of the technology’s operation highlight how the discharge cycle, in which the CO2 is evaporated and heated to power the turbine, is designed to be flexible so that plants can respond to different grid needs rather than following a one-size-fits-all pattern. The goal is to bridge the gap between when renewables generate power and when consumers, including data centers, actually use it, with each facility tailored to local conditions. Reports on the rollout note that Dec coverage of Google’s program describes how the company is rapidly deploying huge CO2 battery facilities and stresses that there is no one-size-fits-all configuration.
How the domes fit into Google’s 24/7 clean energy plan
Google’s broader clean energy strategy hinges on matching its electricity use with carbon-free generation on an hourly basis, not just over the course of a year, and that is where long-duration storage becomes indispensable. Batteries are used to keep excess energy generated by renewable sources, such as solar and wind, during peak production periods so that it can be dispatched later when generation falls short. In practice, that means CO2 batteries will often charge during sunny midday hours and discharge through the evening, filling in the gaps that would otherwise be covered by gas peaker plants.
The company has explicitly linked its investment in CO2 storage to its goal of running on carbon-free energy 24/7 by 2030, arguing that technologies like Energy Dome’s are necessary to make that target credible rather than aspirational. Public explanations of the program stress that these batteries are part of a portfolio that also includes grid contracts, renewable power purchase agreements and other forms of storage, all orchestrated to deliver round-the-clock clean power. One corporate overview notes that Batteries are used to keep excess renewable energy so that Google can move toward carbon-free energy 24/7 by 2030, and it presents the CO2 systems as a key part of that mix.
Visuals, public perception and the “dome city” future
One reason the CO2 battery has captured public imagination is its striking appearance: a giant inflatable dome that looks more like a sports arena than a piece of grid infrastructure. Photo essays show the white bubble rising above industrial sites, with compressors and piping clustered around its base, turning what might have been an obscure thermodynamic system into a recognizable icon of the energy transition. In my view, that visual distinctiveness matters, because it helps communities and policymakers grasp that long-duration storage is a tangible asset, not just a line item in a climate report.
Short video explainers have leaned into this imagery, describing how this dome could solve one of the biggest challenges facing AI data centers by storing massive amounts of energy in a sustainable way. Other coverage has gone further, suggesting that the energy company behind the technology envisions multiple domes across cities over time, effectively creating a new layer of urban infrastructure dedicated to balancing renewable power. One design-focused analysis notes that The energy company says that its CO2 battery concept could lead to domes across cities over time, while a popular clip simply states that Jul coverage of this dome frames it as a way to save billions in energy costs using a new storage approach.
From first step to global grid-scale ambition
Google itself has been clear that its work with Energy Dome is only the first step in a much larger journey toward long-duration storage. In corporate sustainability updates, the company describes how the technology has already proven its ability to store energy for many hours and release it when needed, and it positions the CO2 battery alongside other early-stage investments in geothermal, advanced nuclear and hydrogen. I read that as a signal that Google expects a diverse mix of firm, clean resources to underpin its future operations, with CO2 storage playing a specific role in multi-hour balancing.
The company’s narrative emphasizes that this is not a one-off experiment but part of a systematic effort to test, validate and then scale technologies that can support a global grid dominated by renewables. It highlights that its first step into long-duration energy storage with Energy Dome is being closely monitored for performance, cost and reliability, with lessons expected to inform future procurement across continents. Internal communications describe this as Our first step into long-duration energy storage with Energy Dome, and they stress that the goal is to store energy when it is abundant and release it when it is needed.
The stakes for AI, data centers and the wider grid
Behind the technical details and corporate pledges lies a simple reality: without reliable, low-carbon power, the AI boom will collide with climate constraints and public backlash. Google’s data centers are already “electricity-guzzling,” and the company has acknowledged that it needs round-the-clock clean energy even when the sun is not shining and the wind is not blowing. The CO2 battery plants are explicitly framed as a way to provide that firm supply, ensuring that AI workloads can grow without driving up emissions or overloading local grids.
Analysts following the rollout note that the idea is to provide electricity-guzzling data centers with round-the-clock clean energy, even when renewables are not producing, and that the CO2 battery plants are expected to reach a massive commercial stage if early projects perform as expected. Visual reports on the technology show dome-shaped CO2 batteries that can supply power when sun and wind fail, with captions emphasizing that they involve no emissions and no rare materials. One technical overview explains that Dec coverage of Google’s launch stresses the goal of round-the-clock clean energy for data centers, while another photo story notes that Photos of Google’s dome-shaped CO2 battery highlight its ability to supply power when sun and wind fail and that it uses no emissions and no rare materials.
What comes next for CO2 batteries
As these 200 MWh CO2 batteries move from Sardinia to Wisconsin and beyond, the key questions will be cost, reliability and community acceptance. If Energy Dome can consistently deliver plants that charge by drawing CO2 from a gasholder dome, store it under pressure and then discharge through a turbine without major performance issues, the technology could become a standard option for utilities and large power users. Google’s involvement gives the concept a powerful early customer, but long-term success will depend on whether regulators, grid operators and local residents see the domes as safe, affordable and compatible with their landscapes.
For now, Google is positioning the CO2 battery as a practical tool rather than a futuristic gadget, one piece of a broader effort to align its AI ambitions with the physics of the power system. The company’s investments in Energy Dome, its support for projects like the Columbia 200 MWh plant and its emphasis on 24/7 carbon-free energy all point toward a future in which long-duration storage is as common as gas turbines are today. In that sense, the giant white domes rising near data centers and substations are not just novel infrastructure, they are early markers of how the digital economy might finally learn to live within the limits of a decarbonized grid, a shift that began when Jul updates on how the technology works signaled that long-duration storage had moved from concept to deployment.
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