CO2 . battery renewable energy storage system

The basis behind Energy Dome's CO2 battery technology is that CO2 expands rapidly when it goes from liquid to gas. At room temperature, 2,5675 liters of liquid CO2 held at 56 atm pressure will expand into 1,000 liters of CO2, nearly 400 times larger. Energy Dome's batteries use giant domes with elastic bubbles filled with CO2. The company "charges" the battery by using energy to run an electric compressor that shrinks the volume of the gas until it condenses into a liquid, which is stored under pressure at room temperature. This charging process generates wasted heat. This heat will be collected into the thermal energy storage system.

Energy Dome's experimental 4 MWh capacity renewable energy storage system.

As long as the pressure remains constant, CO2 remains liquid for a long time. When energy is needed, the system uses stored heat to evaporate CO2. A series of turbines collect energy while the CO2 expands and returns to the dome of the bubble.

According to Energy Dome, the round-trip efficiency of this solution is more than 75%. In this respect, the system cannot compete with large lithium batteries. But the cost of storage is only 50 - 60 USD/MWh for a few years, much lower than 132 - 245 USD/MWh when using lithium batteries. CO2 batteries have a reaction rate close to lithium batteries, while storing energy longer and with less system degradation.

After its establishment in February 2020, Energy Dome announced the construction of its first plant in Sardinia and put it into operation in 2022. The Sardinia plant is relatively small, storing only 4 MWh of electricity but helps to prove the design. works well. Energy Dome's next goal is to build a life-size machine that can store 200 MWh of electricity and be operational before the end of 2023.