Commercial viability a prize catch
RESEARCH into capturing carbon emissions has moved from theory to hard- headed commercial practice, with large- scale carbon capture and storage likely in about eight years, according to CO2CRC.
‘‘ We already know a great deal about how to capture carbon dioxide emissions from power stations,’’ CO2CRC chief technologist Barry Hooper said. ‘‘ In fact, we have the pieces of the puzzle to go from capture at source to sequestration in an underground or under- seabed reservoir. The focus of our research now is to put those pieces together in a way that is commercially viable.’’
He points to a major study by CO2CRC which shows the technical feasibility of capturing about 90 per cent of the carbon emitted from Victoria’s power generating facilities in the Latrobe Valley — about 50 million tonnes a year — and storing it permanently underground deep below gas fields in the offshore Gippsland basin.
There have been several successful sequestration tests at various sites around Australia and overseas. The Sleipner offshore gas production facility in Norway, for example, sequesters about a million tonnes of carbon a year and has been operating for a decade.
The principles of capture are not new. The most common methods include solvent absorption into chemicals, membrane capture, which uses layers of polymers to separate carbon dioxide molecules from waste emissions, and the use of solid surfaces to remove carbon dioxide in a process called adsorption.
New materials are being developed and tested all the time, especially with adsorption processes. CO2CRC researchers at Monash University are currently examining materials similar to silica gel. And trials have already moved out of the laboratory with a new range of solvents being tested at Victoria’s giant Loy Yang A power station.
Capture is only the first step in the process. The carbon dioxide is separated to over 95 per cent purity and then compressed into a highdensity fluid for transport to the sequestration site. The process is costly, not just in dollars but in the energy required. It could add as much as 35 per cent to the energy needed to run a power station, as well as the energy costs of liquefaction and transport.
‘‘ If it was absolutely required, it would be possible to set up a carbon capture and sequestration system quite quickly,’’ Hooper says. ‘‘ But as things stand, it would be extremely expensive, with consumers ultimately having to pay through much larger power bills. So we are looking at ways to reduce the costs, from materials and methods used, to the establishment of capture facilities and their integration with existing equipment, to the energy required.
‘‘ We are very aware that there are still a lot of unknown factors about the costs. We are watching the debate over the carbon trading scheme very closely — that will be very important for this area of research. Another big part of the picture is the regulatory framework at state and commonwealth levels.
‘‘ It is very useful, on the subject of costs, to look at the introduction of desulphurisation technology, which was introduced as a regulatory requirement in the 1970s to reduce acid rain and pollution. For power stations this represented a very significant outlay, and in the first few years the cost was considerably more than predicted.’’
However, after five years or so, the cost of the technology began to drop dramatically, as research was refined and desulphurisation became a regular part of operations. These days, no one thinks about desulphurisation equipment as anything special, it’s just part of the process of generating electricity.
‘‘ In engineering- based industries, you see this pattern — large outlays followed by consistent cost reductions — again and again. I expect that we will see it in carbon capture and storage technology as well.’’
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