Energy Dome has officially launched the world's first pilot project of carbon dioxide batteries in the province of Nooro in Sardinia, Italy, storing only 4 MWh of energy and a maximum output of 2.5 MW. The company said the battery's performance was in line with expectations in terms of long range and round-trip efficiency, and it plans to build another 20 MW/200 MWh fully commercialized project by the end of 2023.
The pilot project is located in an industrial area with an existing power connection, and is planned to be operated commercially on the grid as a stand-alone energy storage to provide the grid with the most needed regulatory services. Sardinia is currently powered by coal and will phase out fossil fuels by 2025. Carbon dioxide batteries can be used with wind and solar power.
Energy Dome's CO2 batteries save space compared to compressed air systems. Carbon dioxide expands dramatically as it transitions from liquid to gas, and it stabilizes only at pressures at least five times higher than Earth's atmospheric pressure. The Energy Dome's battery uses a giant dome with a huge, flexible pouch filled with carbon dioxide gas. It "charges" the battery by using energy to run an electric compressor, squeezing the gas into smaller and smaller volumes, and eventually condensing it into a liquid that is stored at ambient temperature. This charging process generates waste heat that is collected into a thermal energy storage system. As long as the pressure remains the same, the carbon dioxide will be there for a long time. When energy is needed, the system uses its stored heat to vaporize carbon dioxide, and as the carbon dioxide expands to the dome, a set of turbines feed the energy back into the grid. Energy Dome says this solution has a round-trip efficiency of over 75 percent. Its levelized storage cost will reach $50-60 per MWh in a few years, much lower than the $132-245 per MWh using lithium batteries.
Energy Dome recently signed a partnership agreement with Italian utility A2A to build a 20 MW facility with five hours of storage capacity. The company also signed an agreement with industrial group Ansaldo to develop and build long-duration energy storage projects in Italy, Germany, the Middle East and Africa.
