As the climate clock keeps ticking, a Federal Government committee is soon to decide where to commit half a billion dollars to reduce Australia’s green house gases.
One possible solution is called ‘Geosequestration’. It involves capturing and burying carbon dioxide from coal-fired power stations instead of releasing it into the atmosphere.
Will this ambitious plan work and will it work in time?
As the Prime Minister warms up the debate on nuclear energy, and scientists say signs of global warming are more pronounced than ever, Catalyst revisits a story Mark Horstman filed for the program two years ago.
Narration: Life as we know it is under threat.
Our planet is heating up faster than we’ve ever known.
2005 NEWS REPORT: Ninety percent of this Antarctic peninsula is melting fast.
Narration: Climate catastrophe is on our doorstep.
2006 NEWS REPORT: Last year was the hottest on record, with nothing to account but global warming.
Narration: We need an escape plan that can save us in time.
President Bush: Nuclear power helps us protect the environment! And nuclear power is safe!
Prime Minister Howard: Nuclear power is cleaner and greener than other forms of power.
Narration: But there’s still plenty of faith in coal.
President Bush: Do you realise we’ve got 250 million years of coal? Coal has got environmental hazards, but I’m convinced technology can be developed so we can have zero-emissions coal-fired electricity plants.
Prime Minister Howard: We’ve already done an enormous amount in relation to reducing greenhouse gas emissions from coal.
Narration: Some would say, that’s not enough.
Dr Iain MacGill: With what the climate science is telling us you know, this is a problem of incredible urgency, and we need to be taking actions now.
Narration: The climate clock is ticking. Science tells us that to keep the temperature liveable, we have to cut greenhouse emissions by at least 60 percent by 2050. So where do we start?
Mark Horstman: Carbon dioxide ...plants breathe it in, we breathe it out. It’s a natural part of the world. But the problem is that we’re making too much.Now you might think that most of it comes from traffic. In fact, that accounts for only about 14 percent. The biggest sources of carbon dioxide in Australia are power stations.
Narration: Australia has 24 large power stations supplying 80% of our electricity. At their hearts are massive furnaces that burn coal.. more than a quarter of a million tonnes of it every day.
Mark Horstman: How hot is it in there?..1600 degrees..1600 degrees!
Narration: Out of this process come exhaust gases containing carbon dioxide.
Dr Chris Spero: If you look at the top of the stack, you don’t see anything coming out because it’s been cleaned.
Narration: The visible smoke is filtered out but the invisible carbon dioxide is still being pumped into the air.. blanketing the planet and trapping in heat.
Narration: A radical solution has been proposed.
It’s called GEOSEQUESTRATION.
Here’s the plan. We keep using coal but instead of pumping carbon dioxide into the air, capture it in the power station, compress it into liquid CO2, pipe it to a suitable location, then inject it deep underground in rock formations where it would remain trapped for thousands of years.
But can such an extraordinary idea work and will it work in time?
The Australian government is trusting it will. Lowering emissions from energy is its main strategy to deal with climate change, and hopes for geosequestration are high.
Two years ago, the Howard Government announced a half-billion dollar fund to make it happen.
Prime Minister Howard, 2004: If you start with the fact that we are a major supplier of growing world energy needs, it seems to me to be a matter of common sense that you try and make those energy uses cleaner, and things like geosequestration are part of that and how great a contribution it will make in the years ahead, I can’t tell you at the moment. I don’t know enough about it.
Narration: And neither do most Australians. So before locking ourselves into a coal future we need a reality check to find out if geosequestration can really help us meet the 2050 deadline or if it’s just a pipe dream.
Mark Horstman: So how much CO2 are we really talking about? And how big is the engineering challenge to deal with it?
Well this drum holds 200 litres. Imagine a pile of these drums that runs for 10 kilometres that way, 5 kilometres that way, and stacks up 10 drums high. More than 1300 million of them.
That’s how much CO2 pours out of our 24 coal power stations. Not every year, that’s just in one day.
Now the gas has to be compressed into a liquid to inject it underground. But even that leaves a huge volume to process. It squashes down into a lake of drums 1 kilometre square. And remember, that’s every day.
Narration: Techniques to scrub or filter the CO2 out of power station exhausts are still being tested in the lab. But in the real world the main obstacle is that the CO2 is mixed up with a massive amount of other exhaust gases.
Mark Horstman: About how much of that is carbon dioxide?
Dr Chris Spero: About 15% by volume would be carbon dioxide, about 20% by mass.
Mark Horstman: That’s a lot of gas to scrub if you want to grab that little bit of carbon dioxide?
Dr Chris Spero: That’s one of the issues with the economics of it is capturing the CO2 from such a dilute stream.
Narration: Chris Spero says that we’re not going to see CO2 scrubbers bolted onto existing power stations because it is simply too expensive. He’s hoping for government funds to help launch a new technology, where the coal can be burned in pure oxygen - a process called ‘oxyfiring’.
Dr Chris Spero: Using oxyfiring we’re able to concentrate the amount of CO2 in the flu gas to 85-90%, which means that the equipment that we use to capture the CO2 can be so much smaller and therefore a lot cheaper.
Narration: This means all of our existing power stations will have to undergo major modifications. But there may be a better option one that uses coal for energy in a completely different way.
David Harris: This is the only one of it’s kind in Australia.
Narration: David Harris is trialling a process called coal gasification which turns coal into gas enabling the carbon dioxide to be separated before combustion.
Dr David Harris: The best way to get the carbon dioxide is out is a process that delivers the carbon dioxide in a high concentration, high pressure form. That’s the reason why we are looking at coal gasification as a core technology for power generation.
Narration: There’s a catch… this means replacing all our power stations with brand new ones. But many of our existing stations still have lifespans of 15, 20, even 50 years with more of the same on the way… so whichever way you look at it these changes will come at a cost.
Barry Hooper: If one’s talking about traditional power stations or even the more advanced energy systems that are likely to be needed to reduce the cost of capture the efficiency reductions could be in the order of 6 to 12 per cent.
Mark Horstman:So does that mean in effect we have to burn more coal to make more power to catch more carbon dioxide?
Barry Hooper: Yes, there is an energy penalty to actually capture, purify, compress and actually store the CO2, and that’s an unavoidable fact.
Narration: And there’s still the problem of where we’re going to put all this CO2 if we do manage to capture it. The answer might lye in this warehouse in Canberra thousands of core samples from drilling for oil and gas contain vital clues of where to look.
Dr John Bradshaw: This rock is around 120 million years old and this whole core that we’re going to be looking at represents about a million years in terms of time.
Narration: John Bradshaw is leading the search of Australia’s underworld looking for safe places to store liquid carbon dioxide.
Mark Horstman: What makes this a good kind of rock for storing liquid carbon dioxide in?
Dr John Bradshaw: I’ll grab some water here, and you can see one of these very nicely sorted sands. And you put the water on there. You can see it disappearing and flowing into that sand.
Mark Horstman: So even though it looks like a rock, there’s still space between those grains?
Dr John Bradshaw: There would be nearly 20% of that rock which is space and pores as we call them which are connected together.
Narration: These rock reservoirs or saline aquifers are being explored using Virtual Reality technology.
Dr John Bradshaw: The ideal site would be a geological feature which is like a dome shape. Across the top of the dome would be a thick muddy seal like a shale rock.
Narration: These storage sites need to be close to the power stations and Victoria, Western Australia and South East Queensland all have possible sites within 350 kilometres of power stations.
But NSW, which produces more CO2 than anywhere else in the country, doesn’t have the right geology.
Dr John Bradshaw: We’re doing more work up in the Sydney region, and there’s possibly better zones up there but at the moment it doesn’t look good. So there are options – because of Sydney’s huge volume, to actually build a pipeline all the way to offshore Victoria.
Mark Horstman: With the first pilot project about to start in Victoria, the future would mean a new network of pipelines criss-crossing the country many times larger than the existing oil and gas pipelines. The engineering is huge and challengingbut people have other nagging questions about storing carbon dioxide underground.
Dr John Bradshaw: The first questions are how do you keep it down there and will it leak?
Narration: If at some time in the future CO2 leaked out, it would drive the world into dangerous climate change even faster but nature suggests there’s a more immediate threat. 1986 news report: As international aid continues to flow in to Cameroon there’s been a national day of mourning.
In 1986 a deadly eruption of volcanic CO2 bubbled up from the waters of Lake Nyos suffocating 1800 villagers and thousands of animals.
Could such a natural leak be re-created by geosequestration? We’re told the trick is to keep the CO2 buried deep enough so it remains as a liquid not a gas.
Dr Brian Evans: Australia would have absolutely no intention to inject the fluid as anything other than a liquid and maintain it as such. Now that in Australian terminology, that requires perhaps greater than 900 meters. Any plans that are in place currently with saline aquifers is in the order of 2 kilometres plus.
Narration: From his laboratory, Professor of Geophysics, Brian Evans, can mimic what happens 2 kilometres underground.
Using a unique pressure chamber fitted with ultrasound, Evans can build an image of where the carbon dioxide moves once it’s been injected into the rock.
He’s convinced that this technology can be used to monitor the buried carbon dioxide and guarantee its safety for thousands of years.
Dr Brian Evans: if we can show that the fluid is no longer moving and it’s static, stationary, then that’s the point where … the operator can say it’s sufficiently stable to say there’s no more going to happen in the future.
However God made the world, not geophysicists and therefore we have to ensure that we are going to monitor it and if something does happen that we have remedial action and it’s already in train before it happens and that’s why we are doing our science.
Narration: To make geosequestration work is an engineering feat on a scale bigger than anything we’ve ever tried in Australia.
It begs the question wouldn’t the effort be better spent on energy technologies that don’t create carbon dioxide in the first place?
Dr Iain MacGill: You know geosequestration’s not an ideal solution when we compare it to the others. It still involves use of fossil fuel and the environmental impacts of that. There are clearly some risks involved in the use of this technology. So if there’s lots of easy other things to do we should do those. We should really be seeing action on those other abatement options such as energy efficiency, renewables and gas generation that are proven. We know they work and we know that they are at reasonable cost.
Mark Horstman: But we’re not, so what is really going on.
Dr Iain MacGill: Good question.
Narration: And it’s a question that’s still relevant today… will geosequestration save the planet or just save the coal industry?
How long before we find out?
Barry Hooper: in the next five to 10 years we will be having demonstrations and potential commercial applications of various capture technologies.
Dr David Harris: We’re probably looking at 10 to 15 years time
before those are implemented on the standard power station.
Dr Chris Spero: Many years away, many years away. This is not something that we’re going to do next year or the year after or before the end of this decade. We’re probably looking 2015, 2020, 2025.
Narration: So around half the time to our 2050 deadline will have passed before we’ll know if geosequestration is going to work.
If it does we can slow down climate change and buy ourselves some time but whatever happens we’re already dependent on coal and will be for some time yet.
Dr Brian Evans: Maybe in many years to come, and it will be many years to come, then we can reduce our coal-fired power stations, but it’s a long time away, and certainly I would say after I’ve gone.
Mark Horstman: Not in your lifetime.
Brian Evans: Not in my lifetime.
- Reporter: Mark Horstman
- Producer: Paul Faint and Mark Horstman
- Researcher: Leonie Hansell, Paul Grocott, Nicholas Searle
Dr John Bradshaw
Professor Brian Evans
Professor of Geophysics
Dept of Exploration Geophysics, Curtin University
Dr Chris Spero
Technology Mger, CS Energy
Dr David Harris
CSIRO Centre For Advanced Technology
CO2 Capture Program Manager
Department of Chemical and Biomolecular Engineering
University of Melbourne
Dr Iain MacGill
Senior Lecturer in Energy Systems
School of Electrical Engineering and Telecommunications