A New CO2 Battery Can Halve the Cost of Solar Energy Storage

Confronting the key weakness of solar.
Chris Young

Energy Dome just announced the close of its $11 million Series A funding round. The Italian company will use that new money to develop and demonstrate the technology for its CO2 Battery, which will greatly enhance solar energy storage, a press statement reveals.

The CO2 battery will store solar renewable energy during the day when there is a surplus of energy, and release it at night and during peak hours. It will also greatly reduce the problem of performance degradation faced by lithium-ion battery solutions.

Making solar and wind energy 'dispatchable 24/7'

With massive new solar farm projects under development, such as the U.S.'s $1.5 billion, 13,000-acre Mammoth Solar Farm, the world increasingly needs efficient methods for storing renewable energy. According to Energy Dome, its "modular, scalable energy storage solution will allow for solar and wind generation to be dispatchable 24 hours per day."

Unlike lithium-ion batteries, which degrade significantly in performance after roughly a decade of use, the CO2 Battery maintains the same performance during its 25 years of expected operation time. This means the cost of storing energy will be approximately half that of a lithium-ion battery with an equivalent storage space, Energy Dome explains.

The company's CO2 Battery uses carbon dioxide in a closed-loop cycle, during which it is converted from gas to liquid and then back into gas. The "dome" from which the company gets its name is an inflatable atmospheric gas holder that is filled with CO2 in its gaseous form. When charging, the system uses electrical power from the grid, which powers a compressor that draws CO2 from the dome and compresses it, generating heat that is sent to a thermal energy storage device. The CO2 is then liquified and stored in vessels at ambient temperature, completing the charge cycle.

The cycle is reversed in the discharging process by evaporating that liquid, recovering the heat from the thermal energy storage system, and expanding the hot CO2 into a turbine that drives a generator. The CO2 battery has roughly 200 MWh in storage capacity, Energy Dome says.

The world 'needs effective, low-cost storage'

Energy Dome's latest funding round was led by VC firm 360 Capital and includes investors such as Barclays' Sustainable Impact Capital program, and a climate technology startup accelerator called Third Derivative. 

"Grid systems across the world need effective, low-cost storage to pair with renewable energy," said Claudio Spadacini, founder and CEO of Energy Dome. "We’re excited to be leveraging this investment and agreement to accelerate our deployment of this transformational technology. We thank all of the supporters who made today’s announcement possible."

Importantly, the CO2 battery will not release any CO2 during the charge and discharge processes. Still, the company will likely need a lot of CO2 to scale its system, meaning it may, in the future, be able to use gas extracted by carbon removal plants, such as the direct air capture (DAC) facility under construction in the U.K. Such a development would mean the CO2 battery would greatly enhance our capacity to store renewable energy at the same time as helping the world remove the substance that's making it turn to renewables in the first place.

message circleSHOW COMMENT (1)chevron