Google Bets on CO2 Batteries: 200 MWh Energy Storage Project Turns a Former Peat Plant Into a Grid Solution

On a patch of land in County Offaly, in Ireland's Midlands, where a peat-fired power plant once burned fossil fuels to light Irish homes, a very different kind of energy infrastructure is about to rise. Google and Italian clean energy company Energy Dome have announced a 23 MW/200 MWh CO2 Battery project — the first bilateral commercial agreement between the two companies and a significant step forward for a technology that could reshape how the world stores renewable energy.

The project works on a principle that is elegantly simple in concept but complex in execution. The CO2 Battery uses electricity from the grid — ideally surplus renewable energy generated during periods of strong wind or solar production — to compress carbon dioxide into a dense, high-pressure state. When the grid needs power, the compressed CO2 is expanded through a turbine, generating electricity that feeds back into the system. The carbon dioxide is never consumed or released; it cycles between compressed and expanded states inside a closed loop, functioning as the medium that stores and releases energy on demand.

The approach has several advantages over lithium-ion batteries, which currently dominate the grid-scale energy storage market. CO2 is abundant, non-toxic, and non-flammable — unlike the lithium, cobalt, and nickel that supply chains for conventional batteries depend on. Energy Dome's system relies on off-the-shelf industrial components rather than the critical minerals whose supply is concentrated in a handful of countries and whose extraction carries significant environmental and human rights concerns. The company argues that this approach improves supply chain resilience while delivering storage at a lower cost per megawatt-hour over the system's lifetime.

For Ireland, the project addresses a critical need. The country has set a target of generating 80% of its electricity from renewable sources by 2030, but wind and solar production are inherently variable. When the wind blows hard, the grid often produces more electricity than it can use, and the excess is curtailed — effectively wasted. When the wind dies, the country falls back on natural gas generation to fill the gap. Long-duration energy storage is the missing piece: it captures surplus renewable energy when production exceeds demand and releases it when the wind drops or the sun sets.

The County Offaly site is strategically located near Rhode, on a section of Ireland's electricity network that serves the greater Dublin region and already hosts significant wind and solar installations. Grid congestion in this area frequently limits the output of renewable generators, meaning that even clean energy that could power Irish homes is sometimes left unused because the transmission system cannot accommodate it. The CO2 Battery is designed to absorb that excess and dispatch it during peak demand, reducing both curtailment and the need for expensive transmission upgrades.

The project has already secured land rights, planning approval, a grid connection, and a 10-year capacity contract from EirGrid, Ireland's state-owned transmission system operator. Those are not minor hurdles — grid connection queues and permitting delays are among the most common reasons that energy projects in Europe and North America stall or fail. Energy Dome and Google are entering construction with the regulatory and contractual foundations already in place.

The facility is expected to enter service in 2028, with plans to add a second 200 MWh unit at the same site, creating a larger long-duration energy storage hub in the Irish Midlands. The total 400 MWh capacity would make it one of the largest non-lithium storage installations in the world.

The Ireland project is not Energy Dome's only collaboration with Google. A separate 19 MW/200 MWh CO2 Battery project is under development in Arizona with utility SRP, and the two companies announced a broader partnership last year to scale deployment of the technology globally. The Arizona project, like the Irish one, targets grid congestion and renewable curtailment — different continents, same fundamental problem.

For Google, the investment is aligned with its commitment to operate on 24/7 carbon-free energy by 2030 — a more ambitious target than simply purchasing renewable energy credits to offset fossil fuel consumption. Achieving 24/7 carbon-free energy at every hour of every day requires not just generating clean power but storing it for the hours when the sun is not shining and the wind is not blowing. Long-duration storage is essential to that goal, and Google is positioning itself as both a customer and a catalyst for the technologies that can deliver it.

The symbolism of building a clean energy storage system on the site of a former peat-fired power plant is hard to miss. Ireland's Midlands were for decades defined by peat harvesting — a form of energy extraction that was both locally important and environmentally destructive. The Bord na Móna, Ireland's state-owned peat harvesting company, has been winding down operations as part of a national decarbonization effort, and the Offaly site is one of several former fossil fuel installations being repurposed for clean energy infrastructure.

The broader significance extends beyond Ireland. As data centre energy demand surges — driven by the same AI computing boom that has members of Congress debating whether households should subsidize Big Tech's power bills — long-duration storage technologies like the CO2 Battery could provide a path to accommodating that demand without burning more natural gas or building more fossil fuel plants. The 200 MWh project in Offaly is a demonstration at commercial scale, and its performance will be closely watched by utilities, grid operators, and technology companies around the world.

What This Means For You: The CO2 Battery is not going to replace lithium-ion in your phone or laptop — it is designed for a different problem entirely. But if you pay an electricity bill, this technology could eventually affect how much you pay and how reliably your power is delivered. Long-duration energy storage solves the fundamental limitation of renewable energy: it produces power when conditions are right, not necessarily when people need it. Technologies like the CO2 Battery make it possible to store wind and solar energy for hours, not minutes, and dispatch it on demand. That means less wasted renewable energy, fewer natural gas plants running as backup, and potentially lower costs over time. Google's investment is a signal that one of the world's largest data centre operators sees this technology as viable at scale. If it works in Ireland — and in Arizona — expect to see it deployed in the regions where your electricity is generated.