With 80 percent of Australia’s electricity produced by coal-fired power stations, and emerging economies like India and China stepping up their energy generation from these sources, the race is on to produce viable ways to reduce carbon dioxide (CO2) emissions.

Geosequestration, or the capture and storage of CO2, has been pro-posed as one solution, as it could significantly reduce coal-fired power as a source of greenhouse-gas emissions. But thousands of millions of tonnes of CO2 would need to be stored, and because there aren’t containers big enough, natural storage facilities such as depleted oil and gas fields are being tested.

A portfolio of low emission tech-nologies will be needed to address climate change. Given that coal is a relatively cheap energy source, the extra cost of capturing the CO2 and pumping it underground means that coal-generated power could still be cost competitive with other low-emission sources such as wind and solar power. Further work is needed to develop all these technologies. The stakes are high, and the technology for CO2 burial still faces many challenges. To that end, Australia has committed funding to what is the largest CO2 burial research project in the world – the Cooperative Research Centre for Greenhouse Gas Technologies (CO2CRC) Otway Project.

The project's aim is to demonstrate that CO2 can be transported and stored underground in Australian conditions and to develop reliable monitoring systems. The site in the Otway Basin, with its sources of natural CO2, depleted gas fields and natural gas fields, is a logical location for a pilot project. The project involves extracting high concentration CO2 gas for an existing well and compressing this gas to a supercritical state – the point at which CO2 acts as a liquid.

This CO2 material is then injected into a depleted natural gas field where it is monitored to determine if the gas has migrated out of the storage reservoir. Stage 1 of the project has been completed, a full seismic survey of the area is being conducted and the project is moving into Stage 2.

The chief executive of CO2CRC, Peter Cook, says 60,000 tonnes of CO2 has been stored two kilometres underground. “The project has shown that CO2 can be safely injected, securely stored and effectively monitored,” he says. “Then Stage Two will allow us to improve how we do this in deep reservoir rocks, known as saline formations.”

CO2CRC is also working on two carbon-capture projects in Victoria: a post-combustion capture project in the Latrobe Valley that focuses on the reduction of emissions from brown-coal power stations, and a pre-combustion pilot project.