ImImagine storing clean electricity inside one of the very gases responsible for climate change. It might sound counterintuitive, but compressed carbon dioxide (CO₂) energy storage – often dubbed the “CO₂ Battery” – is emerging as a game-changing technology. By bottling energy in CO₂, this approach promises to bridge the gap between intermittent renewable generation and round-the-clock power supply. Major players are taking notice: Google recently announced a partnership to deploy CO₂ Battery projects globally, calling it a “promising” solution for 24/7 clean energy blog.google. From pilot plants in Italy to upcoming projects in the U.S., India, and beyond, compressed CO₂ storage is quickly moving from bold idea to real-world deployment. In this report, we’ll break down how this technology works, its advantages and disadvantages, environmental implications, scalability and economics, and the latest developments – all in accessible terms for anyone curious about the future of energy storage.
How Compressed CO₂ Energy Storage Works
At its heart, a CO₂ energy storage system is a closed-loop thermodynamic “battery” that uses carbon dioxide gas as the working fluid. The concept is comparable to compressed air energy storage, but with a crucial twist: CO₂’s physical properties make it exceptionally efficient for this role. Here’s a step-by-step look at how it works:
- Charging (Storing Energy): When there is surplus electricity (for example, on a sunny or windy day when solar panels and wind turbines produce excess power), the system uses that electricity to compress CO₂ gas drawn from a large storage dome en.wikipedia.org. Compressing the CO₂ to about 70 bar pressure greatly heats it (around 400 °C) en.wikipedia.org. The hot, pressurized CO₂ is then passed through a heat exchanger where the heat is extracted and stored in a thermal energy storage medium (often a hot thermal oil or similar) energy-storage.news. With the heat removed, the CO₂ cools and condenses into a liquid (CO₂ uniquely liquefies at ambient temperature under high pressure, unlike air which requires extreme cold) en.wikipedia.org, energy-storage.news. The liquid CO₂ is collected and held in pressurized storage tanks. Essentially, the surplus electricity is now stored as pressure in the liquid CO₂ and heat in the thermal store.
- Discharging (Releasing Energy): When the grid needs power (for instance, at night or during peak demand), the process runs in reverse. The liquid CO₂ is pumped back and evaporated into gas by reintroducing the stored heat via the heat exchanger en.wikipedia.org. This turns the CO₂ back into a hot, high-pressure gas. The expanding CO₂ gas is then directed through a turbine (or turbo-expander), causing it to spin – much like steam escaping a pressure cooker can spin a turbine blade blog.google. The turbine in turn drives a generator, producing electricity that is sent back to the grid. After expanding and cooling, the CO₂ returns to the low-pressure dome as gas, ready to be stored and used again en.wikipedia.org. The entire cycle is closed-loop: the same CO₂ circulates throughout, and no CO₂ is consumed or released during normal operation.
This CO₂ battery essentially stores energy in two forms – as compressed/liquefied CO₂ (potential energy of pressure) and as stored heat. When charged, it’s like a coiled spring full of energy; when discharged, the “spring” uncoils to generate power. The ability of CO₂ to easily transition between gas and liquid at ambient temperatures is the key to the system’s efficiency energy-storage.news. As Ben Potter, an Energy Dome executive, explains: “CO2 has a critical state of 31 °C. That means if you put it under pressure at ambient temperature, it liquefies… as a liquid it’s very high-density… you don’t need cryogenic equipment, and you don’t have efficiency losses. It’s a really good fluid to store energy” energy-storage.news. In simpler terms, using CO₂ avoids the extreme cooling needed for liquid-air storage and packs more energy into a smaller volume than compressed air can en.wikipedia.org.
Advantages of CO₂ Energy Storage
Using compressed CO₂ for energy storage offers several compelling advantages, especially for large-scale and long-duration applications:
- High Energy Density & Ambient Temperature Operation: CO₂ can be liquefied at room temperature under pressure, enabling much higher energy density than traditional compressed air systems. Liquid CO₂ stores about 66.7 kWh per cubic meter, compared to just 2–6 kWh/m³ for typical compressed air – meaning far more energy can be stored in a given volume en.wikipedia.org. And unlike cryogenic liquid air storage, a CO₂ battery doesn’t need ultra-low temperatures (−192 °C for liquid air) – the CO₂ stays liquid at ambient temperature in pressurized tanks en.wikipedia.org. This avoids costly refrigeration and reduces energy losses, boosting overall efficiency.
- Uses Common, No-Conflict Materials: A CO₂ storage plant is built from off-the-shelf industrial components and abundant materials. It’s basically “carbon, steel, water and CO₂,” as Energy Dome puts it energy-storage.news. The system requires no lithium, cobalt, or rare earth metals, unlike conventional batteries energydome.com. All major parts – compressors, heat exchangers, turbines, and inflatable gas domes – are standard equipment from the oil & gas, power, and biogas industries en.wikipedia.org, energy-storage.news. This means the technology can leverage existing supply chains and manufacturing capacity, avoiding the resource constraints and geopolitical issues associated with mining battery metals. “Our CO₂ Battery uses no lithium or rare-earth elements to store electricity,” Energy Dome notes, highlighting that it relies on readily available components energydome.com.
- Long Duration with No Degradation: The CO₂ battery excels at long-duration storage (8 to 24+ hours), filling a gap where lithium-ion batteries struggle economically beyond ~4 hours blog.google. Moreover, the system does not suffer from cycle life degradation like chemical batteries do. Utilities expect a 30+ year service life with essentially no capacity fade over tens of thousands of charge-discharge cycles utilitydive.com. The CO₂ doesn’t “wear out” from being compressed and expanded, and the mechanical equipment can be maintained or replaced as needed. This gives it a huge longevity advantage – a CO₂ plant can keep delivering its full 8+ hours of energy for decades, whereas lithium battery cells gradually lose capacity each year.
- Competitive Efficiency and Cost: CO₂-based storage can reach a round-trip efficiency around 75% (meaning 75% of the electrical energy put in is returned) en.wikipedia.org, utilitydive.com. This is on par with or better than other long-duration options (pumped hydro or liquid air) and not far below Li-ion batteries (typically ~85–90%). Crucially, developers claim it can hit these efficiencies in any climate – “the performance of the system is independent of ambient temperature… you still get 75% roundtrip efficiency even in Alaska or Texas” energy-storage.news. In terms of economics, CO₂ storage is projected to be significantly cheaper for long durations than lithium-ion. Early estimates put the cost around €200–220 per kWh of storage capacity for the first 200 MWh-scale units energy-storage.news, popularmechanics.com – roughly half the per-kWh cost of a 4-hour lithium battery system as of a couple years ago en.wikipedia.org. As the technology scales and benefits from mass production, costs could drop further; Energy Dome believes they can reduce capital costs by ~44% after the first few dozen identical units, thanks to economies of scale and supplier agreements energy-storage.news. Lower cost and high efficiency mean CO₂ batteries could deliver stored renewable power at a very competitive price-point.
- Safe and Site-Flexible: Unlike hydrogen or fuels, CO₂ is non-flammable and inert, reducing fire or explosion risks. The storage dome is essentially an inflatable “big balloon” holding CO₂ at low pressure – if torn, the gas would simply escape and disperse. “Worst case… you lose the CO₂, and wind basically disperses it,” says Energy Dome’s Ben Potter, noting they have modeled accidental leak scenarios and are comfortable with the safety profile energy-storage.news. A CO₂ plant is also site-independent and topography agnostic energydome.com – you don’t need special geology (as with underground compressed air or pumped hydro), just a plot of flat land to install the dome, tanks and machinery. It can be built in deserts, near existing power plants, or co-located with renewable farms. In fact, pairing a CO₂ battery with a solar farm (to store midday solar for nighttime use) could turn intermittent solar into a firm 24/7 resource with as little as a ~6% land footprint added for storage energy-storage.news. All these factors make the technology quite scalable and deployable in many regions.
Industry experts are optimistic about these benefits. For instance, after evaluating various storage options, utility executive Raja Sundararajan of Alliant Energy said “Energy Dome’s CO₂ battery stood out as a cost-effective, efficient and scalable solution”, predicting their first 200 MWh project could be “the first of many CO₂ batteries” to come utilitydive.com. And in launching a 160 MWh project in India, NTPC’s Chairman Gurdeep Singh highlighted the CO₂ Battery’s “very long lifetime (>25 years), no need of critical minerals… [and] minimal performance degradation – unlike [chemical] BESS”, calling it a “landmark development” for long-duration storage energydome.com. These advantages suggest compressed CO₂ could play a pivotal role in our clean energy future.
Disadvantages and Challenges
No energy technology is perfect, and compressed CO₂ storage comes with its own set of challenges and limitations that must be acknowledged:
- Large Footprint and Infrastructure: A CO₂ battery plant is not compact – it’s essentially a small power plant with sizeable components. The most visually striking feature, the inflatable dome, and the array of steel storage tanks require a considerable land area. Estimates suggest a full-scale 20 MW/200 MWh CO₂ facility might occupy on the order of 12 to 25 acres (5–10 hectares) of land popularmechanics.com. One analysis notes this is roughly equivalent to the area of a 3–4 MW solar PV farm popularmechanics.com. In other words, if paired with a large solar installation, the storage would add a single-digit percentage to the total land required energy-storage.news – but it’s still a significant land use, larger than an equivalent lithium-ion battery farm which can be housed in containers or buildings. Such a dome-based plant may face siting hurdles in densely populated or land-scarce areas. It’s also a fixed, heavy infrastructure – not modular or easily movable – which means it’s geared for utility-scale, stationary applications only (unlike battery packs that can scale down to homes or EVs).
- CO₂ Handling and Safety Concerns: Storing thousands of tons of CO₂ under pressure raises understandable safety questions. CO₂ is nontoxic and does not combust, but it is a heavy gas that can displace oxygen. A sudden large release in a confined or low-lying area could pose asphyxiation risks for living beings nearby. Preventing leaks and structural breaches is therefore critical. Engineers stress that the system is designed with safety in mind – the dome operates at low pressure (just above atmospheric) and is made of durable fabrics similar to biogas holders en.wikipedia.org. In worst-case scenarios (e.g. a tornado strikes the facility), the expectation is the CO₂ would simply vent and dissipate into the atmosphere without causing harm energy-storage.news, en.wikipedia.org. Nonetheless, these risks must be managed through proper siting (open areas, away from populated basins), monitoring, and robust engineering. The idea of a “giant bag of CO₂” has prompted skepticism; as Popular Mechanics wryly noted, a “big ol’ bag of still-air CO₂ could be a problem if somehow ruptured” popularmechanics.com. Public perception and trust will need to be addressed through transparent safety testing and regulation.
- Mechanical Complexity and Maintenance: Unlike a chemical battery, which has no moving parts, a CO₂ storage plant relies on machinery – compressors, expanders, pumps, fans, etc. These introduce more points of potential failure and require regular maintenance, much like a traditional power station. The system’s round-trip efficiency and economics depend on all components operating optimally. Downtime for repairs or reduced performance due to wear could impact revenue. Additionally, constructing a CO₂ plant is a larger project with more on-site assembly compared to installing modular battery units. This complexity means longer lead times and potentially higher upfront project development overhead. While the components are proven in industry, integrating them into a new application at scale carries execution risk. It’s worth noting, however, that the reliance on established equipment also means the technology doesn’t need a breakthrough in materials – just solid engineering and project management.
- Competition and Rapid Battery Progress: Perhaps the biggest challenge is the competitive landscape. Energy storage is a hotbed of innovation – from lithium-ion improvements to flow batteries, thermal storage, gravity storage, and more. The CO₂ battery will need to prove it can deliver value better or cheaper than these alternatives. Lithium-ion costs have fallen dramatically and factories worldwide churn out Li-ion batteries at scale, giving them a manufacturing advantage. As Popular Mechanics observed, conventional batteries are “already mass produced and relatively modular, meaning they’re a bit more plug-and-play than a massive CO₂ battery plant” popularmechanics.com. There’s a risk that by the time CO₂ systems are deployed widely, next-generation electrochemical batteries (or other solutions) might undercut them on cost or convenience. The Verge noted the CO₂ battery “faces stiff competition” in the energy storage arena, even if it does have “unique strengths” theverge.com. This means CO₂ technology must continuously innovate and drive costs down to stay relevant.
- Early-Stage Commercial Track Record: As of 2025, compressed CO₂ energy storage is still in early days of commercialization. Only one small demonstrator (4 MWh in Sardinia) has been fully operational for a few years en.wikipedia.org. The first large-scale projects (200 MWh class) are just beginning construction. Thus, real-world data on long-term performance, maintenance costs, and reliability is limited. Energy planners and financiers may view it as a promising but unproven technology until a fleet of projects is up and running. This can make financing initial projects harder without government or strategic support. There’s also the challenge of educating stakeholders – it’s a novel concept to store energy in CO₂, and overcoming the “mental hurdle” may take time. The bankability of the technology will improve as pilot projects successfully operate and hit their targets. In the meantime, developers often seek grants, government funding, or partnerships (as we’ll see below) to jump-start deployments and validate the technology at scale.
Despite these challenges, proponents are quick to point out that no single storage solution will dominate; a variety of technologies will work in concert. The long-duration niche (8+ hours) that CO₂ storage targets is one that lithium batteries alone may not fill due to economics and resource limits. Thus, even with competition, there is a strong impetus to have options like the CO₂ battery proven and ready. As Justine Calma of The Verge put it, this technology’s unique strengths “could accelerate the transition to clean energy” if it can overcome the remaining hurdles theverge.com.
Environmental Implications
Using CO₂ itself as an energy storage medium has some intriguingly green implications, even though CO₂ is typically seen as a villain in climate change:
On the positive side, a CO₂ battery enables deeper integration of renewable energy, directly helping reduce fossil fuel use. By storing surplus solar or wind power and delivering it when renewable output is low, it provides a clean buffer that can replace gas peaker plants or coal-fired evening generation. This means fewer greenhouse gas emissions from the power sector, tackling the root cause of climate change. In essence, the technology turns CO₂ from a problem into part of the solution. As one journalist quipped, Energy Dome’s approach is “combating decarbonization with… more carbon” – an ironic idea that could pay off popularmechanics.com. Every megawatt-hour of renewable energy shifted to when it’s needed is a megawatt-hour not generated by fossil fuels.
Moreover, the resource and pollution footprint of CO₂ storage is relatively low. It avoids mining of lithium, cobalt, or nickel, which not only have environmental impacts but also often involve energy-intensive processing. The main inputs – steel for tanks and machinery, and CO₂ gas – are industrial commodities with well-understood supply chains. CO₂ used in these systems can be sourced as a byproduct from industries (or even captured from the air), and it remains in a closed loop rather than being emitted. Over the system’s decades-long life, there’s minimal waste: no toxic battery chemistries to dispose of, and the steel and equipment are recyclable. Additionally, unlike huge pumped hydro reservoirs, a CO₂ plant doesn’t significantly alter land or water use beyond the facility footprint.
However, there are environmental risks and considerations to manage. A major one is the potential release of the stored CO₂. While not poisonous, CO₂ is a greenhouse gas; an accidental large leak would effectively be a one-time emission roughly equal to the CO₂ inventory (for a 100 MWh system, about 2,000 metric tons CO₂ are in circulation energy-storage.news). For context, 2,000 tons CO₂ is about the amount 430 cars emit in a year. It’s not catastrophic in the global sense (and far less than the emissions the system saves by enabling renewables), but it’s something to prevent. Fortunately, catastrophic releases are deemed unlikely with proper design, and any small chronic leaks would be detected and can be mitigated (the CO₂ can be topped up if needed). Another consideration is the manufacturing impact: building the compressors, turbines, and steel tanks does entail carbon emissions upfront (embedded energy), so the system must operate for some years on clean energy to “pay back” that carbon footprint – similar to wind turbines or other infrastructure. The long lifespan (25+ years) helps ensure a good environmental return on investment.
In terms of local environmental impact, the CO₂ battery is fairly benign. It doesn’t produce air pollution or effluent in operation. Noise is one possible factor – high-power compressors and turbines can be loud, so soundproofing or adequate siting might be needed to avoid disturbing nearby communities or wildlife. Visually, the dome is a noticeable structure (often depicted as a white blimp-like dome), which could be considered an eyesore by some; though compared to tall wind turbines or transmission towers, its profile is relatively low. And when a CO₂ plant is eventually decommissioned, the site can be restored much more easily than, say, a coal mine or large dam.
All told, compressed CO₂ energy storage is considered an environmentally friendly technology in the context of enabling a carbon-free grid. It cleverly repurposes a greenhouse gas into a tool for reducing greenhouse emissions. As Popular Mechanics mused, “If CO₂ can do good rather than harm, then let’s put it to work.” popularmechanics.com This ethos captures the appeal: transforming CO₂ from a waste product into a workhorse for clean energy.
Scalability and Economic Viability
For any new energy technology, the big questions are: Can it scale up to have a meaningful impact? And can it compete economically in the market? The outlook for compressed CO₂ storage is increasingly encouraging on both fronts, though challenges remain.
Scalability: CO₂ energy storage appears highly scalable, primarily because it leverages established industrial components and doesn’t require rare materials. Manufacturers of turbines, compressors, and gas holders are already capable of producing these at large sizes and volumes. Energy Dome’s strategy has been to standardize a design (a 20 MW module with ~200 MWh storage) and then repeat it like a product. “Standardisation is the key to industrialising energy storage,” says Energy Dome, drawing a parallel to how wind turbines became cheaper by mass-producing a few standard models energy-storage.news. Since each CO₂ battery plant is built from repeatable components, scaling up mostly means scaling production and deployment, not reinventing new tech for each project. There is no inherent geophysical limit – unlike pumped hydro which needs specific valleys or caverns, a CO₂ system can be built wherever needed (given land and grid connection). This means the technology could potentially be deployed in many regions worldwide, including flat areas, deserts, or even offshore on platforms (conceivably).
Already, we see momentum in scaling: the first demo was 2.5 MW, the next units are 20 MW, and there’s no technical barrier to even larger units if demand arises (or linking multiple domes for greater capacity). Because it’s a closed loop, adding more storage hours (bigger tanks and dome) or more power (additional compressor/turbine capacity) is a relatively straightforward engineering choice. Modularity is also possible – for instance, a facility could install multiple smaller domes rather than one giant dome if needed, operating in parallel. The main scaling challenges are logistical and financial: it requires significant capital investment per project and skilled project execution. However, with heavyweights like utilities and even Google now backing the tech, the pathway to scale looks much more solid than a few years ago.
Economic Viability: On economics, the CO₂ battery targets a sweet spot – long-duration storage – where it can potentially outshine alternatives. Its capital cost per kWh for 10+ hour systems is projected to be substantially lower than using banks of lithium-ion batteries energy-storage.news. For example, a 10-hour, 200 MWh (20 MW) CO₂ plant might cost on the order of $200–250/kWh to build todayenergy-storage.news, popularmechanics.com, whereas achieving 10-hour storage with Li-ion could easily cost double that (since you’d need roughly 2.5× the batteries of a 4-hour system) and involve battery replacements over time. The levelized cost of storage – which accounts for lifetime and efficiency – is where CO₂ systems aim to excel. Thanks to no degradation and a long life, a CO₂ battery can spread its capital cost over more cycles and years. And because it doesn’t incur fuel costs (it just stores energy) and has minimal operational expenses (mostly for maintenance and the small power needed for pumps/fans), its ongoing costs are low. These factors contribute to a potentially very competitive cost per MWh delivered, especially for daily cycling storage.
That said, early units are first-of-a-kind and not yet mass-produced, so they rely on funding and visionary customers. Governments and big investors are indeed stepping up to support the economics initially. Notably, the U.S. Department of Energy selected CO₂ battery projects for $30 million in grants as part of advancing long-duration storage innovations energy-storage.news. The European Investment Bank and Breakthrough Energy Ventures (Bill Gates’ climate tech fund) have together committed about €60 million to help scale up Energy Dome’s projects in Italy energy-storage.news. And in July 2025, Google’s parent company Alphabet invested in Energy Dome and inked a strategic partnership to deploy the tech, seeing it as a way to obtain affordable 24/7 clean power for Google’s operations by 2030 energynews.pro. These endorsements not only provide capital but also signal confidence in the economic promise of CO₂ storage.
One important aspect of viability is the market need for long-duration storage. Studies by organizations like EPRI (Electric Power Research Institute) have found that as grids approach high renewable penetration, the value of 8+ hour storage soars blog.google. The LDES (Long Duration Energy Storage) Council, an industry body, estimates that up to 8 terawatts of long-duration storage could be deployed globally by 2040, potentially saving $540 billion per year for energy systems by optimizing grid reliability and renewable utilization blog.google. If these projections hold, there is a massive market awaiting technologies that can economically fill that niche – and CO₂-based storage is a prime contender. Policymakers are also starting to recognize this; for example, a few U.S. states like California have set procurement targets for long-duration storage specifically, which create opportunities for solutions like CO₂ batteries.
However, short-term market structures can be a hurdle. Today’s electricity markets tend to reward fast, short bursts of energy (for frequency regulation or peak shaving), where 4-hour lithium batteries shine. The challenge for long-duration systems is monetizing multi-hour storage – often it requires new contract structures or incentives (like capacity payments or renewable firming contracts). Energy Dome’s team has noted that widespread adoption may depend on “market mechanisms, with fixed remuneration over 20+ years” for long-duration storage, akin to how renewables were fostered energy-storage.news. Essentially, the technology is ready, but business models and policies are catching up. The good news is that trends are moving in the right direction: more utilities are issuing RFPs for 8-hour storage, and government programs are de-risking initial projects.
In summary, compressed CO₂ energy storage is on a viable trajectory. It scales using known industrial methods, and its economics improve at larger scale and longer durations, making it a strong candidate to supply the medium-to-long duration storage that future clean grids will demand. As deployment ramps up and costs fall further, it could complement shorter-duration batteries and other storage solutions, together creating a resilient, carbon-free energy system.
Current Developments and Projects (as of 2025)
Though still an emerging technology, compressed CO₂ storage has moved rapidly from concept to concrete projects around the world. Here are some of the notable developments, pilot projects, and commercial deployments underway as of August 2025:
- Sardinia, Italy – Pilot and First Full-Scale Plant: The Italian startup Energy Dome (pioneer of the CO₂ Battery concept) built a 2.5 MW / 4 MWh demonstration plant on the island of Sardinia, which began operation in June 2022 en.wikipedia.org. This pilot facility successfully proved the concept by dispatching stored energy to the Italian grid for over three years blog.google. On the same site, Energy Dome, together with partner Ansaldo Energia, has begun constructing a standard 20 MW / 200 MWh CO₂ Battery plant – one of the world’s first commercial-scale CO₂ storage systems en.wikipedia.org. This full-scale unit (designed for ~10 hours storage) is expected to be commissioned in late 2024 or early 2025 utilitydive.com. The company reports a expected round-trip efficiency of ~75% and a projected cost around €220/kWh, roughly half the cost of lithium batteries in 2023 en.wikipedia.org. Importantly, this Italian project received backing from the EU; in 2023 the European Innovation Council provided €17.5 million in support energy-storage.news, and in 2024 the European Investment Bank agreed (contingent on milestones) to co-fund it with €60 million alongside Breakthrough Energy Ventures energy-storage.news. These investments underscore the strategic interest in making the Sardinia plant a success as a blueprint for future CO₂ storage deployments across Europe.
- Wisconsin, USA – 20 MW / 200 MWh Utility Project: In a first-of-its-kind move for the United States, Alliant Energy is partnering with Energy Dome to build a 20 MW / 200 MWh CO₂ Battery system in Wisconsin. Called the Columbia Energy Storage Project, this 10-hour duration facility will be located near a retiring coal plant in Columbia County, WI energy-storage.news, utilitydive.com. State regulators approved the project in July 2025 energy-storage.news, following a supply contract signed in late 2024 energy-storage.news. Construction is slated to begin in 2026 and finish by end of 2027, aligning with the coal plant’s shutdown timeline utilitydive.com, energy-storage.news. The Wisconsin project will serve as a critical demonstration in the U.S. context, with support from the DOE’s Office of Clean Energy Demonstrations (which awarded it up to $30.7 million in cost-share funds) utilitydive.com. It’s a collaborative effort: local utilities Madison Gas & Electric and WEC Energy are co-owners, and partners like Shell and EPRI are involved in testing and evaluation utilitydive.com. Alliant’s interest was driven by a thorough review of available technologies – the utility found the CO₂ system’s use of off-the-shelf components, >75% efficiency, and 30-year lifespan with no degradation particularly appealing utilitydive.com. “We see this as the first of many CO₂ batteries to be built in partnership between Energy Dome and Alliant,” said Alliant’s strategy VP Raja Sundararajan utilitydive.com, indicating that if this pilot succeeds, larger rollouts could follow across the utility’s service area.
- Karnataka, India – 20 MW / 160 MWh Project at NTPC: India’s largest power producer, NTPC Ltd., announced in early 2025 a landmark project to deploy a CO₂ Battery at its site in Kudgi, Karnataka. This plant will have a storage capacity of 160 MWh (with a 20 MW output), and is being executed by India’s Triveni Turbine Ltd. in partnership with Energy Dome as the technology provider energydome.com. It’s the first long-duration CO₂-based storage project in the country and aligns with India’s push for “Atmanirbhar” (self-reliant) clean tech – many components will be sourced or manufactured domestically energydome.com. NTPC’s Chairman Gurdeep Singh praised the move, highlighting the system’s >25-year life, lack of critical minerals, and 100% depth of discharge, saying a successful demonstration “shall open new vistas in the field of Electrical Energy Storage” energydome.com. The project is seen as a technology showcase: if it performs well, it could be replicated at other NTPC facilities and even exported to global markets via Indian industry energydome.com. For Energy Dome, cracking the Indian market is significant given the country’s enormous energy storage needs to support its renewable energy targets. The NTPC project is expected to help validate the CO₂ battery under India’s climatic conditions and grid requirements, potentially paving the way for broader adoption in Asia.
- Global Partnerships – Google and Oman: A major recent development (announced July–August 2025) is Google’s strategic partnership and investment in Energy Dome, aimed at accelerating global deployments of CO₂ storage. Google plans to install CO₂ Battery systems to help power its data centers and operations with 24/7 carbon-free energy by 2030 blog.google. This includes backing specific projects in multiple regions. For instance, Google and Energy Dome are working with the government of Oman on what could be one of the first large-scale CO₂ storage + solar projects in the Middle East energynews.pro. Oman’s sovereign wealth fund (OIA) had already invested in Energy Dome via a previous round, and a local entity, Takhzeen Oman, was set up to deploy the tech energynews.pro. With Google’s involvement, plans may fast-track for a high-capacity CO₂ battery paired with a solar farm in Oman’s sunny environment, storing solar energy by day and releasing it at night energynews.pro. Eng. Nawaf al Balushi, managing director of Takhzeen Oman, called the Google partnership “a major global milestone” for the technology that could “support greater integration of renewable energy into the power grid” energynews.pro. This kind of project would demonstrate the CO₂ battery at a utility scale in a desert climate, and could serve as a model for other countries in the region looking to firm up solar power. Google’s broader support also means we might see CO₂ storage units popping up near Google’s facilities in the U.S., Europe, or Asia, wherever they can help meet round-the-clock clean power goals blog.google. The backing of a tech giant like Google not only provides capital but also operational know-how and a guarantee of initial demand for the systems.
- Other Noteworthy Moves: In Europe, Danish renewable leader Ørsted has explored the feasibility of a 20 MW / 200 MWh CO₂ battery installation, indicating interest from wind farm operators in using the tech to stabilize outputenergy-storage.news. Several other utilities and energy companies are reportedly in discussions or early agreements with Energy Dome (the company mentioned multiple contracts signed in Italy, the U.S., and Asia) blog.google. The Long Duration Energy Storage (LDES) Council included compressed CO₂ in its 2022 report of promising technologies, and governments in countries like Germany and Australia have grant programs where CO₂ storage could compete. While Energy Dome is currently the clear front-runner in this space with its patented CO₂ Battery™, academic researchers and a few companies have also been investigating CO₂-based thermal storage cycles (for example, a team at University of Genoa in Italy has studied CO₂ for energy storage applications en.wikipedia.org). We may see additional players or variations on the concept emerge, spurred by the successful demos.
In summary, as of August 2025 compressed CO₂ energy storage is transitioning from theory to practice. The first wave of projects – in Italy, the U.S., India, and potentially the Middle East – will be crucial in proving the technology’s performance at scale. They are being closely watched by the energy industry. If they deliver as expected in terms of efficiency, cost, and reliability, we can expect a rapid scale-up in the latter half of the decade. Many countries are in need of long-duration storage by 2030 to hit their climate targets, so a viable CO₂ solution coming to market now is timely. The next couple of years will likely bring a string of “firsts” on every continent for this novel approach to energy storage.
Conclusion
Storing energy by compressing carbon dioxide might have sounded like science fiction a decade ago, but today it’s a reality on the cusp of wider adoption. This compressed CO₂ energy storage technology – the so-called CO₂ Battery – offers a compelling way to make renewable energy truly dispatchable, by taking an abundant gas we usually think of as waste and turning it into a working medium for clean power. We’ve seen how it works in a closed loop to store electricity as pressure and heat, then give it back when needed, and how it brings advantages like long life, no rare materials, high energy density, and potentially lower costs for long durations. We’ve also discussed the hurdles it faces: significant land footprint, the need for rigorous safety, competition from ever-cheaper lithium batteries, and the usual challenges of scaling up a new technology.
Crucially, compressed CO₂ storage is not developing in a vacuum – it’s part of a bigger picture in the energy transition. Grids of the future will likely use a portfolio of solutions: fast batteries for short bursts, thermal and mechanical systems for long hauls, and maybe even hydrogen for seasonal storage. In that mix, the CO₂ battery is staking a claim as a reliable, efficient option for daily shifting of solar and wind energy. Early deployments by innovative utilities and the backing of firms like Google indicate a growing confidence that this technology is ready to step onto the world stage.
Will CO₂ batteries replace lithium batteries? Probably not in all cases – but they don’t have to. Instead, they fill a different niche where lithium struggles: delivering power through the night or through multi-day lulls in renewables, without breaking the bank or relying on fossil fuel backup. Every region that’s serious about decarbonizing its grid is watching the progress in Sardinia, Wisconsin, and Karnataka to see if CO₂ can live up to its promise. If it does, we may soon see giant CO₂ domes quietly helping keep our lights on with clean energy across the globe.
As we stand in 2025, the CO₂ energy storage story is just beginning. The next few years will likely bring record-breaking projects and valuable lessons. But the trend is clear – this once-counterintuitive idea has moved from the lab to reality, and could play a starring role in the clean energy revolution. In the words of Energy Dome’s CEO Claudio Spadacini, his CO₂ battery is “intended to switch energy from day to night… that is the main need you have with a wind and solar-dominated grid” popularmechanics.com. In simpler terms: it makes sunshine and wind available whenever we need them. And if CO₂ can do good rather than harm, then let’s put it to work popularmechanics.com in service of a sustainable energy future.
Sources
- Energy Dome – CO₂ Battery Technology Description en.wikipedia.org
- Energy-Storage.News – Interview with Energy Dome’s Ben Potter (Apr 2023) energy-storage.news
- Google Blog – “Our first step into long-duration energy storage with Energy Dome” (Jul 2025) blog.google
- Utility Dive – “Alliant and Energy Dome sign deal for first CO₂ battery in U.S.” (Oct 2024) utilitydive.com
- Energy Dome Press Release – “NTPC joins forces with Energy Dome” (Jan 2025) energydome.com
- EnergyNews.pro – “Google partners with Energy Dome in Oman” (Aug 2025) energynews.pro
- Popular Mechanics – “Turning Carbon Dioxide Into Power” (Jul 2024) popularmechanics.com
- The Verge – “Meet the CO₂ Battery…” (Oct 2022) theverge.com
