Carbon Dioxide Put To Work For Long Duration Energy Storage

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Carbon dioxide reaches a liquid state when compressed and it expands with a pop when released, and now the Italian startup Energy Dome is ready to harness the action for a new energy storage system that could provide far more storage at far less cost than conventional lithium-ion battery arrays. Energy Dome’s first project is getting under way in Italy with completion expected before the end of next year. A second project is already in the pipeline for the US state of Wisconsin, too.

CO2 For Long Duration Energy Storage

With the climate crisis looming overhead, long duration energy storage systems have been described as the key to unlocking vast reserves of intermittent wind and solar energy at a more rapid pace.

Lithium-ion battery arrays are currently the go-to medium for storing excess wind and solar energy. However, the state of battery technology typically allows for about 4-6 hours of storage, with newer systems topping out at eight hours. That’s enough to accomplish daily grid management tasks, but the work will pile up as higher volumes of renewable energy flow into grid systems. For future grid resiliency, energy planners are seeking a minimum of 10 hours in storage capacity, ideally reaching a full day or much longer.

The idea of using liquid CO2 for energy storage is simple enough, now that low cost renewable energy is at hand. During periods when renewable energy output is high but electricity demand is low, grid managers have to order curtailments in wind or solar capacity. With a CO2 storage system, the excess kilowatts can be put to work running compressors that convert a large volume of CO2 gas to a smaller volume of liquid. When released from compression and heated, the CO2 expands back to a gas and is put to work running turbines to generate electricity.

Energy Dome crossed the CleanTechnica radar last year with a new “CO2 Battery” storage system. The company earned a place in BNEF Pioneers program of the influential Bloomberg NEF energy research organization, based on its potential for achieving long duration energy storage of up to 24 hours. The system is relatively simple, deploying expandable bladders as a storage platform.

“To ice the long duration energy storage cake, Energy Dome claims that its system is based on proven technologies with non-flammable, non-toxic materials, and that it maintains its performance level for 25 years and possibly longer,” we noted.

A New CO2 Storage System For Italy

In the latest development, on Friday Energy Dome announced that it has gained project-level funding to begin work on its first “thermo-mechanical energy storage system,” in the municipality of Otttana, in the Sardinian province of Nuoro. The euros are coming from Breakthrough Energy Catalyst (up to €35,000,000) and the European Investment Bank (€25,000,000 via Invest EU), through a partnership between Breakthrough and the EU.

“This combined investment is an endorsement of Energy Dome’s ready-to-be-deployed, long-duration energy storage proposition. Energy Dome’s robust performance (high round-trip efficiency) and capital expenditure requirements are significantly more competitive than the Lithium-Ion benchmark, providing a solution to the critical problem of utility-scale long-duration energy storage, which is at the core of the renewable energy transition,” Energy Dome states.

The Sardinia project will consist of the company’s standardized 20-megawatt, 200 megawatt-hour CO2 Battery. It meets the 10-hour long duration milestone described by the US Department of Energy, among others.

“The CO2 Battery does not use materials from rare metals and its main components are based on already existing and known supply chains enabling job creation within Europe,” Energy Dome adds.

$30 Million For Long Duration Energy Storage In Wisconsin

Commercial operation is expected by Q3 2024 for Energy Dome’s project in Italy. Meanwhile, energy planners in Wisconsin are eagerly awaiting their own 20-megawatt CO2 Battery under the forthcoming Columbia Energy Storage Project. The plan is to submit project details to state regulators next year, with an eye on beginning construction in 2025 at a site in the Town of Portage.

The project will be up and running in 2026 if all goes according to plan. That may have been a somewhat dicey proposition some years ago, when Wisconsin had a rocky relationship with renewable energy in general and wind power in particular. More recently, though, the momentum has gone to the clean tech side.

In fact, Wisconsin stakeholders are anticipating that the new storage system will serve as a model for replication all around the US, and some heavy hitters are involved.

The lead US stakeholder behind the CO2 Battery project is the Wisconsin public utility Alliant Energy, which received a grant of up to $30 million from the US Department of Energy for the Columbia project. In addition to funding from the Energy Department, partners in the project include WEC Energy Group, Madison Gas and Electric, Shell Global Solutions US, the California-based Electric Power Research Institute, University of Wisconsin-Madison, and Madison College.

“Guided by our purpose-driven strategy, we continue to invest in cost-effective, sustainable energy solutions for the customers and communities we proudly serve,” enthused John Larsen, Alliant CEO and board chair. “As we diversify our energy mix, the added capacity and unique capabilities of energy storage solutions will strengthen our generation portfolio, increase grid resilience, improve reliability and help us continue to meet customer needs.”

More Long Duration Energy Storage For The USA

As another indication that the Wisconsin project is anticipated to be the first of many, it was funded through the Energy Department’s Office of Clean Energy Demonstrations, which launched in 2021 with a $25 billion mandate from the Bipartisan Infrastructure Law to “help scale the emerging technologies needed to tackle our most pressing climate challenges and achieve net zero emissions by 2050.”

OCED has set a high bar for the projects in its long duration energy storage portfolio. In addition to scooping more wind and solar energy into the grid, long duration projects are expected to improve critical infrastructure, emergency response, grid stability and management systems, and transmission systems with a particular focus on rural areas, including communities where energy costs are high.

Long duration energy storage is also expected to help defer or outright avoid new costs associated with transformers, substations, and other transmission and distribution infrastructure. Providing for EV fast-charging stations is another priority, among other tasks.

On top of all that, projects that qualify for OCED funding have to submit a community benefits plan. OCED lists community and workforce engagement, workforce investment, energy and environmental justice, and diversity, equity, inclusion, and accessibility, among the elements of a qualifying project.

The Columbia project “builds on an ongoing partnership between Alliant Energy, Columbia County and the Ho-Chunk Nation by supporting their shared goals of advancing sustainable energy solutions and expanding economic opportunities,” OCED explained in a funding announcement issued in  September.

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Image: Energy Dome long duration CO2 energy storage system for wind and solar energy (courtesy of Energy Dome).