As global electricity demand surges—driven by AI expansion and cloud services—Google has taken a strategic step into long-duration energy storage (LDES), partnering with Italian firm Energy Dome to scale its CO₂-based storage technology across key international markets. The move marks the tech giant’s first major engagement with LDES, positioning it at the intersection of grid reliability, decarbonization, and energy innovation.
Strategic Fit: Data Centers and Dispatchable Clean Energy
Data centers already consume up to 1–1.5% of global electricity, and with AI training workloads growing exponentially, that figure is set to climb. For Google, matching this demand with 24/7 carbon-free energy (CFE) isn’t just an ambition—it’s embedded in corporate commitments and future regulatory compliance. While solar and wind provide variable input, long-duration energy storage remains a missing link in the company’s clean energy strategy.
Energy Dome’s “CO₂ Battery” offers a thermal-mechanical solution tailored for storage durations between 8 and 24 hours—timeframes that conventional lithium-ion batteries are neither cost-effective nor technically suited to serve. Google’s strategic investment in the company, whose Sardinia-based 2.5MW/4MWh pilot has operated since 2022, provides both a commercial validation and a path to scalability.
Technology Assessment: The CO₂ Battery in Context
Unlike lithium-ion BESS, Energy Dome’s approach is based on adiabatic CO₂ compression. Electricity charges the system by compressing carbon dioxide gas, which is then stored in liquid form. Upon discharge, the CO₂ is expanded through turbines using recovered heat from the compression stage, generating electricity in a closed thermodynamic loop.
From a mechanical standpoint, the system mimics established industrial processes—borrowing from turbomachinery, gas storage, and thermal management disciplines. This compatibility with existing supply chains and EPC knowledge is often cited as a key driver of its cost-effectiveness.
Unlike electrochemical batteries, which degrade with each cycle and require rare materials, the CO₂ Battery claims stable cycling and minimal degradation risk. However, broader industry comparisons remain limited by the lack of published cost-per-kWh data at scale, a metric essential for benchmarking against vanadium flow batteries, pumped hydro, and compressed air storage.
Grid Integration: Inertia and System Stability
One notable dimension of the CO₂ Battery is its mechanical inertia, provided via rotating turbomachinery. As conventional thermal power plants are retired, power systems are grappling with inertia deficits—once a passive byproduct of spinning generators, now a required engineering input for frequency stability.
While advanced inverters in grid-forming BESS can synthetically replicate inertia, Energy Dome’s technology offers physical inertia plus storage capacity, placing it in a unique category alongside synchronous condensers with added energy value. This dual-function capability may appeal to grid operators facing both decarbonization targets and system balancing challenges.
Project Pipeline and Market Dynamics
The first commercial-scale project, a 20MW/200MWh plant in Sardinia backed by Engie, serves as a template for replication. A twin project in Wisconsin, co-developed with Alliant Energy, recently cleared state-level regulatory hurdles. In India, Energy Dome secured a 20MW/160MWh deployment contract with state-owned NTPC—signaling interest beyond OECD markets.
While Google has yet to announce specific project sites, its operations span Europe, North America, and the Asia-Pacific regions, where renewables already contribute substantial shares to grids. In these geographies, curtailment of excess solar and wind power remains a growing issue. LDES technologies like the CO₂ Battery may offer a flexible way to convert surplus clean generation into a time-shifted dispatchable supply.
Investment Signal: Google’s Shift from Procurement to Enablement
Until now, Google’s energy strategy has centered on direct procurement—such as its 2024 solar-plus-storage deal with Intersect Power and its hydroelectricity partnership with Brookfield. This partnership with Energy Dome reflects a pivot: from consumer of clean power to enabler of clean power infrastructure.
By investing early in first-of-a-kind commercial technologies, Google joins a small but influential group of corporates (alongside Amazon and Microsoft) attempting to bridge the “valley of death” between pilot validation and commercial bankability. This approach mirrors strategies in other hard-to-abate sectors, where public capital has proven insufficient to underwrite deployment at speed or scale.
Remaining Unknowns and Market Implications
Despite the progress, several questions remain. Energy Dome has yet to publish levelized cost of storage (LCOS) metrics at scale, and thermal efficiency losses inherent in any compression-expansion cycle need closer scrutiny. Moreover, the carbon lifecycle of CO₂ sourcing, though a closed loop, may face regulatory or public perception hurdles if misinterpreted.
Nevertheless, the alignment with Google’s carbon-free ambition provides reputational and commercial momentum for Energy Dome. If the pilot replications in Wisconsin and Sardinia deliver consistent performance, and if the India project proceeds as scheduled, the CO₂ Battery may soon challenge the notion that LDES must come from electrochemistry or pumped storage alone.
For now, Google’s foray into this space is a signal to the broader market: dispatchable, long-duration clean energy is no longer a luxury—it’s becoming a necessary layer in the architecture of digital infrastructure.
