Depleted Gas Reservoirs Can Double as Geologic Carbon Storage Sites

A demonstration project on the southeastern tip of Australia has helped to verify that depleted natural gas reservoirs can be repurposed for geologic carbon sequestration, which is a climate change mitigation strategy that involves pumping CO₂ deep underground for permanent storage. The project, which includes scientists from Lawrence Berkeley National Laboratory (Berkeley Lab), also demonstrated that depleted gas fields have enough CO₂ storage capacity to make a significant contribution to reducing global emissions. During an 18-month span beginning in April 2008, an international team of researchers injected 65,000 tonnes of CO₂-rich gas two kilometers underground into a depleted gas field in western Victoria, Australia. That's about 130 tonnes of CO₂ per day, or the amount emitted by a small, 10-megawatt power plant. It's also the daily CO₂ emissions required to supply 6000 average U.S. homes with electricity. Extensive monitoring conducted during and after the injection found no measureable effect of stored CO₂ on soil, groundwater, or the atmosphere. "There was no discernible leakage.