The Australian
June 10, 2006
Impressive advances are being made in clean coal technologies, writes Andrew Trounson
IT seems almost too good to be true. Can we really make our dirty coal-fired power stations green? Have we discovered the silver bullet to slay the monster that has transformed our abundant coal reserves into sources of evil greenhouse gases?
As the Prime Minister's crusade to reassess the potential for nuclear power gained momentum this week, the coal industry was claiming that by the time nuclear power could become a reality in Australia, the technologies for effectively plugging greenhouse gas emissions from coal power plants will have been commercially proven.
The idea is to commercialise technologies that "clean" coal before it is burnt to bring down emissions closer to natural gas, which generates about half the emissions of brown coal. Carbon dioxide emissions would then be captured and compressed into almost liquid vapor that could then be piped to geological sites and injected hundreds of metres underground.
But while achieving this energy nirvana for the world's coal resources is feasible, it will be expensive, making alternative sources, such as natural gas and renewables, such as sun and wind, relatively more competitive.
According to numbers from the National Generators Forum that represent the country's main coal and gas-fired generators, by 2015-20 the generating cost of coal with carbon capture and burial, or sequestration, will be roughly the same as that for nuclear and wind.
Critics such as the environment lobby are concerned that carbon capture and sequestration technologies are unlikely to be widely enough employed to significantly cut global emissions until 2020 or more. That, they say, is too long a wait while we continue to burn coal, and that we should stop building new coal-fired plants and extending the life of new plants in favour of proven gas and renewable energy. It is why Victoria's decision last year to extend the life of the Hazelwood brown coal power plant from 2009 to 2031 so angered the environment lobby and renewable energy industry.
Nevertheless, there hasn't been a new coal-fired plant built in either Victoria or NSW in the past 10 years, with new capacity already largely coming from gas.
The seductive attraction of the self-styled clean coal technologies is the huge potential gain to be had from sequestering carbon emissions from coal, given its importance as a power source.
Australians get nearly 80 per cent of their electricity from coal-fired generation and the country has coal resources big enough to last hundreds of years.
And despite the threat of climate change, the energy-hungry populations of China, India and the rest of the developing world will be demanding ever more cheap fossil fuels to raise them out of poverty.
Globally, fossil fuels are expected to remain the planet's primary energy source until at least 2050, by which time scientists warn that we need to have stabilised carbon levels in the atmosphere or face serious, and in some places devastating, climate change. Many already think climate change is under way with the rising incidence of floods, hurricanes and other events.
China, where coal supplies 69per cent of the country's power, is effectively installing the equivalent of Australia's total coal power industry every year.
The International Energy Agency expects China to account for 26 per cent of all new global emissions between 2002 and 2030, more than all the emissions from the developed world combined. And in the 20 years to 2025, the IEA expects coal to account for 33per cent of global carbon dioxide growth.
Clearly, finding a solution to coal emissions is where the biggest dividends can be made in cutting global emissions. According to the UN Intergovernmental Panel on Climate Change, scenario analysts suggest that including carbon capture and sequestration in a carbon dioxide mitigation portfolio could cut the cost of stabilising its levels in the atmosphere by 30 per cent or more.
"There is no reason why by 2020 we can't be putting a quarter of our emissions from coal and gas back into the ground, and no reason why by 2030 it wouldn't be about half," Mark O'Neill, chief executive of the Australian Coal Association, says.
It is the huge size of this tantalising alchemist's cherry that has driven the formation this year of the six-nation Asia-Pacific partnership on clean development and climate that is betting on technology to beat climate change.
It brings together Kyoto rebels Australia and the US, with the world's emerging energy consumption giants China and India. In the US the Government has teamed with industry, including coal giants Rio Tinto and BHP Billiton, to invest $US1 billion ($1.34 billion) in the FutureGen project that aims to have the world's first commercial scale emissions-free coal-fired generator in operation by 2012 using carbon capture and sequestration.
In Australia the coal industry is putting $300 million into a technology development fund. Low emission technologies for fossil fuels are also expected to take the bulk of the Government's $500million low-emission fund announced last year, much to the chagrin of the renewable industry that complains the Government is punting too heavily on coal.
There are several low-emission coal demonstration projects under way in Australia aimed at reducing and or capturing coal emissions. But the most important is a $30 million trial of geo-sequestration in Victoria's Otway Basin by the Government-backed Co-operative Research Centre for greenhouse gas technologies.
Late this year the CRC plans to start injecting carbon dioxide underground into an old gas well at Nirranda, 20km east of Warrnambool in western Victoria. It will be piped from a naturally occurring underground reservoir some 2km away, with 100,000 tonnes of the gas to be re-injected underground over two years.
That compares with the 400million tonnes of carbon dioxide Australia emits every year. The CRC estimates that Australia has enough geological capacity to store up to six billion tonnes of carbon dioxide, which, assuming an injection rate of 50 million tonnes a year, would give us 120 years of storage.
But while the capture and sequestration technology is feasible and is used to varying degrees already in the oil and gas industry, the challenges of achieving carbon capture and sequestration shouldn't be underestimated.
To get a feeling for the scale of the undertaking to capture and store coal emissions, it has been estimated that the volume of flue gas emitted by coal-fired power stations across Australia every year is equivalent to about 20 times the amount of natural gas produced every year from Australian gas fields.
Capturing, compressing and storing such vast quantities of gas would be a Herculean undertaking. But since only 14 per cent of this vapour from a coal-fired power station is actually carbon dioxide, the key is using various technologies to strip out the nitrogen, oxygen and water vapour and significantly reduce the amount of gas that needs to be captured.
The other challenge is finding places to store the gas. While potential geological sites have been identified within reasonable distances of population centres in Victoria and Queensland, no such sites have been indentified within a 500km radius of Sydney or Newcastle. In an age when proposals for a gas pipeline between Papua New Guinea and Queensland are close to becoming a reality, this isn't an insurmountable problem, but it adds significantly to the overall cost.
There are also inevitable concerns over the safety of transporting and storing large quantities of concentrated carbon dioxide. Concentrated carbon dioxide is nasty stuff. In 1986, a freak geological disaster released a massive natural bubble of carbon dioxide from under Lake Nyos in Cameroon that asphyxiated more than 1700 people.
However, an IPCC assessment found that piping carbon dioxide posed no greater risk to the public than piping natural gas, and could be lower. And storing the carbon dioxide would involve injecting the gas hundreds of metres underground into reservoir rocks that have held oil and gas for millions of years.
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