Carbon capture costs earth: scientists

Canberra Times

Rosslyn Beeby
Wednesday, 13 September 2006

Capture and storage of greenhouse emissions from Australia's coal-fired power stations will double the cost of producing electricity and could increase carbon dioxide emissions from power plants by about 30 per cent, CSIRO scientists have told a Federal Government inquiry.

They claim at least 3500 large-scale geosequestration sites across the world would be needed to cut global greenhouse emissions by one billion tonnes of carbon dioxide a year.

So far, Australia has only located 100 sites that could be suitable for underground storage of carbon dioxide.

A chemical engineer with CSIRO Energy Technology, Greg Duffy, told a House of Representatives Science and Innovation inquiry into geosequestration - the capture and underground storage of carbon dioxide - that current solvent-based carbon capture technology would add about $35 per megawatt hour to the cost of generating electricity.

It would also reduce electricity output by 30 per cent, requiring more coal to be used and therefore increasing greenhouse emissions and the amount of fly ash waste from coal-fired plants.

"You are going to have to burn more coal because you need energy to drive the capture project," Dr Duffy said, explaining that "the solvents capture the carbon dioxide, but then you have to get the solvents to release the carbon dioxide and you have to put energy in".

Asked by the inquiry's deputy chair, Tasmanian MP Harry Quick, if the "average punter's electricity bill would double" as a result, Dr Duffy replied that if costs were passed on, "yes it would".

It could take between 15 and 20 years and cost "hundreds of millions of dollars" to retrofit coal-fired power stations with carbon-capture technology, he said.

"You would have a huge engineering requirement. You are not going to get it off the ground overnight."

Dr Duffy said that if more efficient carbon-capture technology was developed by 2020, the added cost to electricity production could be reduced to $20 per megawatt hour.

"There are two issues. There is the cost of capturing a tonne of carbon dioxide and then there are the tonnes of carbon dioxide per megawatt hour that are generated by the power station.

"You can look at improving the technology for capturing a tonne of carbon dioxide and you can look at reducing the amount of carbon dioxide that comes from a unit of generation from the power station," he said.

Just over two months ago, federal Science Minister Julie Bishop asked the Science and Innovation Committee to inquire into and report on the science and application of geosequestration, including its potential economic and environmental benefits.

Prime Minister John Howard has frequently referred to geosequestration as a crucial technology to reduce Australia's greenhouse emissions.

But so far, submissions to the inquiry have been negative.

CSIRO petroleum engineer Dr Lincoln Paterson told the inquiry geosequestration was technically feasible but there were significant questions about long-term legal responsibilities for managing geosequestration sites.

At present, geosequestration was not adequately covered by petroleum or environmental laws, and changes to current federal and state legislation were needed.

In a submission to the inquiry, Engineers Australia warned that responsibility for carbon dioxide leaks from underground storage sites would need to be determined and legally enforced.

"There will be risks at carbon capture and compression stage, during transport, during sequestration into the chosen aquifer and for the duration of storage in the aquifer.

"The Australian Government will need to accept responsibility for some elements of these risks," the submission said.

The University of NSW Centre for Energy and Environmental Markets has also questioned the effectiveness and safety of geosequestration, claiming it is likely "to come at a significant cost and is unlikely to make a significant contribution to emission reductions for a decade or more".

The Country Women's Association of NSW criticised geosequestration as an "end-of-pipe solution" to controlling emissions and claims $30million of federal funding used to fund geosequestration trials in Victoria's Otway Basin "would fund an enormous amount of research" into more effective carbon-control technologies. "Higher efficiency fossil fuel use, work on reducing emissions and development of renewable energy sources is required now," the organisation's submission said.