The CO2 Battery Planned for Coal Country
Energy Dome and Victoria's state electricity company signed a partnership in July 2026 to build a 20 MW, 200 megawatt-hour CO2 battery in Australia's Latrobe Valley, a region long powered by coal.
Photo source:
Energy Dome
A Coal Region Planning Its Next Chapter
The
Latrobe Valley in Victoria, Australia, has powered the state for generations,
first through coal and gas plants that are now retiring one by one. Replacing
that power is not simply a matter of adding more solar panels and wind
turbines. Those sources stop producing when the sun sets, or the wind calms, and
a region losing its coal plants needs something that can keep supplying
electricity for many hours at a time, not just minutes.
Victoria's
State Electricity Commission, known as SEC, a state-owned energy company, has
partnered with Energy Dome, an Italian energy storage company based in Milan,
to address that need directly. The partnership, announced in July 2026, will
develop what the companies describe as Australia's first commercial compressed
carbon dioxide battery, planned for a site next to the decommissioned Hazelwood
coal power station in the town of Morwell.
Storing Energy in a Giant Dome of Gas
Energy
Dome's technology stores electricity using carbon dioxide, water, and steel
rather than lithium, cobalt, or other minerals that require mining. The system
works by compressing carbon dioxide gas into a liquid state and holding it
under pressure. When electricity is needed, the liquid CO2 is allowed to expand
back into gas, and that expansion drives a turbine that generates power. The
gas itself is stored in a large dome structure, which gives the technology its
name, and the entire cycle can be repeated for more than 30 years without the
storage capacity declining over time.
The
planned Victorian facility will have a capacity of 20 megawatts and 200
megawatt hours, meaning it can supply a steady 20 megawatts of power for 10
hours straight. That duration matters because most battery storage installed in
Victoria so far runs for only two to four hours, enough to smooth out short
spikes in demand but not enough to cover an extended period without sun or
wind. A 10-hour battery can bridge a full evening, an overnight lull in wind,
or several cloudy days in a row.
Why This Location Was Chosen
The
site was not selected only for its history. The former Hazelwood power station
location already connects to existing electrical substations and transmission
lines built to carry large amounts of power, infrastructure that would
otherwise need to be built from scratch elsewhere. The project is also expected
to employ up to 66 people in a region where coal-related jobs have been
disappearing, and it draws on a local workforce already experienced with the
compressors and turbines that coal plants have used for decades, since Energy
Dome's system relies on similar mechanical equipment.
SEC
has described the project as the first of several planned for a new site called
SEC Energy Works, a 143-hectare precinct the company is developing for
renewable energy and storage projects in the Latrobe Valley. As of the
announcement, the companies stated that planning and design work had begun,
with community and stakeholder consultation underway, though no construction
timeline has been set.
A Technology Already Running Elsewhere
The
Victoria project is new, but the underlying technology is not unproven. Energy
Dome built its first full-scale commercial plant in Ottana, Sardinia, which has
been operating for about a year, supplying power to the Italian utility Engie.
That plant demonstrated the technology at commercial scale before Energy Dome
began signing partnerships in other countries. The company has since agreed to
similar projects in India with utility NTPC, in the United States with Alliant
Energy, and with Google in both Ireland and Arizona to help power the
technology company's data centers with reliable, low-carbon electricity.
In
a January 2026 industry ranking published by research firm Sightline Climate,
Energy Dome placed third overall among long-duration storage providers
worldwide, behind only Tesla and Chint Power, and ranked as the highest-placed
company using a technology other than lithium batteries. The ranking
specifically noted that Energy Dome had two commercial projects that passed
final investment decision, a meaningful distinction in an industry where many
storage technologies remain stuck at the planning stage.
Why Long-Duration Storage Matters as Coal Plants Close
Australia,
like many countries, is retiring coal power faster than it is adding storage
capable of replacing what coal provided: power available at any hour,
regardless of weather. Short-duration batteries help smooth daily demand peaks,
but they cannot substitute for a coal plant that ran continuously.
Long-duration storage, generally defined as eight hours or more, is built
specifically to fill that gap, holding energy from sunny or windy periods and
releasing it during the long stretches when neither is available.
The
Victoria project remains in its early planning stages, and no completion date
has been announced. What it represents so far is a signed commitment between a
state government energy company and a storage provider with a working
commercial track record elsewhere, aimed at solving a specific problem: keeping
the lights on in a region as its old coal plants shut down, using a technology
that does not depend on the same minerals now in high demand across the battery
industry.
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