- Orietta Guerrera
- The Age, July 11, 2008
WITH a small plant fitted to the Loy Yang power station, the long-term viability of diverting its carbon dioxide emissions and capturing it to achieve "near-zero-emissions coal" is being tested.
For the first time in the southern hemisphere, in a process called post-combustion capture, greenhouse gas has been extracted from power station flues after the coal has been burnt.
As part of a pilot program headed by CSIRO's energy technology division, a 10-metre-high plant — designed and built to capture up to 100 tonnes of carbon emissions a year — has been fitted to the power station in the Latrobe Valley.
CSIRO energy technology chief David Brockway said the technology could reduce carbon emissions from coal-fired power stations by more than 85%.
Because the process begins after the coal is burnt, no modifications are needed to the main part of a station. The plant can be added to an existing station, Dr Brockway said.
"This is particularly important because we have such a heavy reliance on coal-fired power stations, and many of our power stations will be around for another 50 years," he said.
The process involves diverting the flue gas to the plant through piping. Carbon dioxide from the gas flues is dissolved in an amine solvent and captured.
The solvent is then passed through another vessel, where it is heated and the carbon is separated and released. It is then compressed into a carbon liquid form, and is ready for the next stage in achieving "near-zero-emissions carbon": sequestration, or storage deep underground.
Different amine solvents will be tested to see how they perform. The main challenge is keeping costs down. If introduced at power stations in its current form, Dr Brockway said, the technology would double the wholesale price of electricity.
Dr Brockway hopes "the world-leading pilot plant program" will move to a demonstration stage and capture 100,000 tonnes of carbon.
He described the pilot as an important milestone to commercialisation of the technology, which many experts agree is 10 to 20 years away.
"The capacity has got to be enormous if we want to capture all of the CO2," Dr Brockway said. "The Latrobe Valley produces about 58 million tonnes per annum."
A plant has been commissioned for the black-coal power station in Munmorah, on the NSW central coast. Another is being built in Beijing, while a third is planned for Queensland.