Compressed carbon dioxide storage preserves energy in this harmless gas, by reducing its volume, thereby heating it. CO2 gas is abundant, and is the primary carbon source for life on Earth. A U.S. company wants to use it for a long-duration storage project, and we report on progress here. But is this idea safe and environmentally responsible?
Using Compressed Carbon Dioxide Gas For Storage
Carbon dioxide gas is ideal for the application. This is because, unlike most other gases, it liquefies under pressure at room temperature. This phenomenon reduces its volume, and could be a cheaper way to store energy than in lithium-ion batteries.
If we wanted to build a 100 megawatt-hour battery, for example, we would need around 2,000 tons of carbon-dioxide gas. We would begin by storing this at atmospheric pressure in a large, flexible container, which could look something like a giant dome.
Next, we would compress the carbon dioxide gas to a pressure of approximately 70 bars. This would heat it to around 400 degrees celsius temperature. Finally, when we needed the stored power, we would pass the super-heated, liquefied gas through a heat exchanger to recover the energy.
Such a compressed carbon dioxide storage battery would have the potential to deliver 100 megawatts of electricity for one hour, or fifty megawatts for two hours, and so on. The project would take up far less space than a comparable battery farm. If the storage container were to burst, then the gas would disperse harmlessly into the atmosphere.
Would Carbon Dioxide Energy Come to Wisconsin?
It sure could, if U.S. company Alliant Energy has its way. The utility has applied for permission to construct an 18 megawatt compressed carbon dioxide storage ‘dome’ in Wisconsin state. This will be the brain child of Italian inventor and entrepreneur Claudio Spadacini,
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Harvesting Carbon Dioxide in a Battery
