As the global demand for electricity surges, the need for effective long-duration energy storage solutions becomes increasingly urgent. Energy Dome, an innovative energy storage company, is addressing this challenge by utilizing compressed carbon dioxide in its large-scale grid batteries. These systems are capable of delivering power for up to 24 hours, providing much-needed stability to renewable energy sources such as solar and wind, which can be unpredictable due to weather fluctuations.
The centerpiece of Energy Dome’s technology is an expansive white dome that spans the equivalent of seven soccer fields, housing approximately 2,000 metric tons of carbon dioxide. The process begins when excess energy, often from solar farms, is used to compress this gas into a liquid form, stored in carbon-steel tanks. This compression generates heat, which is retained in a special thermal storage material. When the grid requires energy, the liquid carbon dioxide is warmed and transformed back into gas, flowing through a turbine to generate electricity before returning to the dome to restart the cycle.
While compressed gas storage is not a novel concept, Energy Dome’s method stands out because it does not rely on specific geological conditions, allowing for broader application and scalability across various regions. The company launched its first commercial facility in Sardinia, Italy, in 2025, boasting a capacity of 200 megawatt-hours—enough to power approximately 18,000 homes for ten hours. With plans for a total of 30 gigawatt-hours of projects spanning five continents, Energy Dome aims to enhance the viability of renewable energy by offering a cost-effective alternative to traditional lithium-ion batteries, particularly for longer storage durations.
Despite its promise, Energy Dome’s technology is still in its infancy, with only one operational project to date. The company’s systems are estimated to be 10% to 15% cheaper than lithium-ion batteries for eight-hour storage solutions, and even more favorable for longer durations. However, the roundtrip efficiency of Energy Dome’s systems hovers around 70%, compared to lithium-ion batteries, which typically achieve 90%. Additionally, while some projects integrate natural gas turbines to increase efficiency, this introduces greenhouse gas emissions, raising concerns about their environmental impact. Looking ahead, Energy Dome’s ability to scale rapidly, combined with its innovative approach, could play a crucial role in meeting the world’s energy demands as the shift towards renewables accelerates.
Source: Energy Dome and its carbon dioxide batteries via MIT Technology Review