Grid operators are racing to keep up with a surge of renewable power and a wave of electricity-guzzling data centers, and the old toolkit of short-duration lithium packs and gas peaker plants is no longer enough. Into that gap steps a new class of “bubble batteries,” grid-scale systems that store energy in pressurized carbon dioxide and promise to deliver clean power for ten hours or more at a stretch. The technology is moving from concept to concrete projects, positioning itself as a mainstream pillar of long-duration storage rather than a niche science experiment.
Instead of stacking more conventional cells, these bubble batteries use thermodynamics to bank surplus solar and wind in tanks of CO2, then release it when the grid is straining after dark. The result is a storage format that looks more like industrial gas handling than consumer electronics, and it is arriving just as global investment in grid batteries, new flexibility markets, and long-duration technologies is accelerating.
Why the grid suddenly needs long-duration storage
The basic problem is simple: variable renewables are becoming the backbone of electricity systems, but the infrastructure that balances them is still stuck in a fossil era. As wind and solar expand, grids must shift large blocks of energy from sunny or windy hours into the evening peak, smooth out sudden ramps, and keep frequency steady when conventional plants are offline. Analysts now frame energy storage as critical to scaling renewables, with Energy storage singled out as a key enabler of higher clean power penetration and a more flexible system.
At the same time, demand is being reshaped by electrification and by hyperscale computing. New data centers are being designed around round-the-clock clean power, and developers are already pairing them with grid-scale bubble batteries to guarantee low-carbon electricity even when the sun is not shining, a trend highlighted in reporting on how grid-scale bubble batteries will serve electricity-guzzling facilities. As renewables rise toward providing 40 per cent of global power generation, large-scale storage is shifting from a nice-to-have to a structural requirement for reliability and cost control.
The limits of today’s lithium grid batteries
Most of the storage built so far relies on lithium technology, which is excellent at fast response but less suited to sitting full for days and then discharging for half a day at a time. According to standard references on grid energy storage, Lithium ion batteries are well suited for short-duration storage under eight hours, in part because of cost and degradation patterns that favor frequent cycling over long, infrequent discharges. That profile matches services like frequency regulation and short peak shaving, but it leaves a gap for multi-day or seasonal balancing.
Real-world deployments reflect this constraint. So-called “big batteries” on the grid today are typically designed for only 2 to 4 hours of output, a far cry from the one-to-two-month buffer that a stockpile of coal once provided for thermal plants, as detailed in an energy storage assessment. Instead of meeting that long-duration need, today’s high-growth, gigawatt-scale storage market is dominated by lithium-ion systems used largely in ancillary, not energy, applications, as one long-duration storage roundup notes with the word Instead underscoring how little of the market is yet focused on multi-hour energy shifting.
Why geography-bound options are not enough
For decades, the workhorse of bulk storage has been pumped hydro, with compressed air following behind, but both depend on very specific terrain. One comparative study of battery chemistries notes that, Unlike pumped hydro storage which relies on specific geographical features, only batteries have flexible land uses and do not require dams or very large lakes near them, a point captured in the term Unlike. That limitation makes it hard to build enough pumped hydro in flat or densely populated regions where demand is growing fastest.
Compressed air faces similar constraints. A review of flexibility options for high renewable penetration explains that, Similar to PHES, the main obstacle to the implementation of CAES is the dependence on specific geographical conditions such as salt caverns, mines, depleted gas fields or aquifers, with the phrase Similar highlighting how both PHES and CAES are constrained by geology. Bubble batteries, by contrast, can be sited on industrial land near substations or data centers, using tanks and compressors rather than mountains or underground caverns.
How bubble batteries actually work
Bubble batteries are essentially thermodynamic machines that store energy in the pressure and phase of carbon dioxide rather than in electrochemical reactions. In a typical design, surplus electricity drives compressors that push CO2 to high pressure, turning it into a liquid and storing it in tanks, then later the fluid is allowed to expand, driving a turbine to regenerate electricity. One flagship implementation is the CO2 Battery from Energy Dome, which uses adiabatic compression of carbon dioxide in a closed loop, as described in approvals for an Energy Dome Battery project in Wisconsin that is designed for ten hours of storage.
The operating principle is straightforward but powerful. During the day, the CO2 Battery uses excess energy from the local grid, normally supplied by solar power, to compress carbon dioxide and store it at high pressure at ambient temperature, unlike air, a process summarized in the phrase During the. When electricity is needed, the CO2 evaporates as part of a thermodynamic cycle, driving a turbine. Technical descriptions of the Columbia Energy Storage Project note that it was Developed by Energy Dome as a closed thermodynamic cycle in which carbon dioxide is compressed, stored, and then expanded to drive a turbine, with the phrase Developed underscoring the company’s role.
Inside Energy Dome’s CO2 “bubble”
Energy Dome’s system is the clearest example of a bubble battery moving toward commercial scale. The company’s technology is a closed-loop system where CO2 is compressed at 60 bars of pressure and turned into a liquid, then later allowed to expand through a turbine to generate power, with the figure 60 capturing the operating pressure. Because the working fluid is contained, the system does not emit carbon dioxide during normal operation, and it can be built from off-the-shelf industrial components like compressors, heat exchangers, and gas tanks.
Projects are now moving from Italy to North America. In Wisconsin, regulators have approved a ten-hour installation that will utilise Energy Dome’s CO2 Battery technology, storing energy via adiabatic compression and then releasing it as the CO2 evaporates as part of a thermodynamic cycle, as detailed in the Energy Dome project description. Another initiative, the Columbia Energy Storage Project, was Developed by Energy Dome to store energy through a closed thermodynamic cycle in which carbon dioxide is compressed, stored, and then expanded, with the Columbia Energy Storage Project using the same underlying process to drive a turbine and generate electricity.
From toy bubbles to industrial domes
The “bubble” label is not just a marketing flourish, it reflects the visual and mechanical reality of these systems. Early patents for bubble-making devices describe machines that create bubbles of all shapes and sizes in a simple and unique method, using a blower and a liquid reservoir to generate a continuous stream, as in a design where The device makes bubbles without requiring physical motion from the user. Bubble batteries scale that idea up dramatically, enclosing large volumes of gas under pressure inside domes and tanks that resemble industrial versions of a child’s toy.
In Energy Dome’s case, the signature visual is a large white dome that houses the gaseous CO2 at low pressure, while separate tanks hold the liquid phase at high pressure. Reporting on how grid-scale bubble batteries will soon be everywhere notes that these installations are being pitched as round-the-clock clean energy sources for data centers, with grid-scale bubble batteries described as a way to provide electricity-guzzling facilities with reliable renewable power even when the sun is not shining. The playful metaphor of bubbles helps explain a complex thermodynamic system to policymakers and investors who are more familiar with lithium racks and gas turbines.
Market momentum: from pilot projects to a global buildout
Behind the technology story sits a rapidly expanding market for grid-scale storage. KEY MARKET INSIGHTS from one industry analysis put the global grid-scale battery market size at USD 10.07 billion in 2023 and project a compound annual growth rate of 18.20% during the forecast period, with the phrase KEY MARKET INSIGHTS highlighting both the 10.07 billion figure and the growth trajectory. Another Grid Scale Battery Market Growth Analysis, Size and Forecast report from Technavio uses detailed Analysis to forecast continued expansion of the Grid Scale Battery Market Growth Analysis, with Technavio pointing to policy support and falling costs as drivers for the Scale Battery Mar segment.
Deployment numbers are already moving. Global grid-scale battery energy storage system capacity has risen sharply, with Global grid-scale BESS deployment reported to have increased by 38% through October, a figure captured in the phrase 38% for Global BESS growth. Analysts tracking the sector argue that They can shift energy, stabilise the grid, and relieve network constraints from a single asset that deploys in 1 to 2 years, with the pronoun They referring to grid-scale batteries as a class. Within that class, long-duration formats like bubble batteries are starting to claim a share of new projects, particularly where developers need 8 to 24 hours of storage.
Why bubble batteries matter for grids and markets
Bubble batteries are arriving just as electricity markets themselves are being rewired for flexibility. European power systems, for example, are shifting toward 15-minute markets, a change described as not just a technical adjustment but a fundamental evolution in how electricity is traded, dispatched, and balanced across the continent, as captured in the phrase This change isn’t just. Long-duration storage that can respond quickly and then sustain output for many hours is well suited to these more granular markets, where price signals reward both speed and endurance.
In North America, Batteries are redefining the way electricity is generated, stored, and distributed, shifting from a novel concept to a strategic asset in the energy transition, as one analysis of Batteries in the US puts it. Bubble batteries extend that strategic role by offering dispatchable, zero-combustion capacity that can replace gas peakers, firm up solar-heavy portfolios, and provide backup for critical loads like hospitals and data centers without relying on diesel. Their ability to store energy for ten hours or more also makes them a hedge against multi-hour transmission outages and extreme weather events.
Canada’s slow start and the policy gap
Not every country is moving at the same pace. In Canada, experts argue that grid-scale batteries improve reliability and cut costs, but Canada has been slow to respond, with one analysis asking Why battery storage is booming elsewhere while Canadian deployment lags, as highlighted in the phrase Why. Another report notes that as renewables surge, providing 40 per cent of global power generation in 2024, large-scale battery storage systems are becoming essential, yet Canada has been slow to respond, a point underscored in the phrase 40 per cent that quantifies the global shift.
For bubble batteries, that policy lag is both a challenge and an opportunity. Jurisdictions that move quickly to recognize long-duration storage in capacity markets, resource adequacy planning, and clean energy standards will be better positioned to attract projects like Energy Dome’s ten-hour installations. Those that delay may find themselves importing technology and power from neighbors that have already integrated grid-scale bubble batteries into their planning, reinforcing the sense that national choices now will shape who benefits from the next wave of storage innovation.
Competing chemistries and the long-duration race
Bubble batteries are not the only contenders for long-duration storage, but they occupy a distinct niche. Flow batteries, for example, are gaining attention for 8 to 24 hour applications, with one report noting that this is especially true for BESS which lasts less than 4-hours, where lithium-ion currently leads the market, while Flow batteries are emerging for medium-duration (8-24 hours) energy storage, as captured in the paired terms BESS and Flow. Each technology brings different trade-offs in efficiency, footprint, and cost, and grid planners are increasingly looking at portfolios rather than single silver bullets.
There is also a push to make the broader battery value chain more sustainable. Projects involving companies like TANIOBIS have set objectives to develop sustainable, energy-efficient processes throughout the HV battery value chain, from raw material extraction to recycling, aiming to close the materials loop, a goal described in detail where The project’s objective was to create such a loop and has now been achieved. Bubble batteries, which rely more on steel, CO2, and industrial machinery than on critical minerals, fit neatly into that sustainability narrative, potentially easing pressure on lithium and cobalt supply chains.
From flares and microgrids to mainstream infrastructure
One of the more intriguing frontiers is the intersection of storage with oil and gas infrastructure. Innovators in the oil field are exploring ways to transform flaring into money and power, with one company seeing use cases where its technology can chemically store excess electricity from the grid and capture gas that would otherwise be burned, as described in a report on how innovators seek to transform flaring into power. Bubble batteries could complement such efforts by providing dispatchable capacity at remote sites, turning stranded gas and surplus renewables into firm electricity for local loads or export.
At the other end of the spectrum, microgrid designers are grappling with how to size storage to handle variable renewables without destroying battery life. One study on isolated microgrids notes that, Moreover, an excess power generation by renewable resources necessitates the charging of the battery, and that extra energy must be either stored or dumped to avoid overcharging, as the word Moreover introduces the challenge. Bubble batteries, with their tolerance for long idle periods and deep discharges, could offer microgrids a way to ride through cloudy days or calm spells without oversizing lithium packs or relying on diesel generators.
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