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The idea of tapping off emissions from coal-fired power stations and pumping them into massive underground caverns has been getting a lot of attention as one potential option for reducing carbon emissions.

ccsBut carbon sequestration has just been knocked back by the United Nations and won’t be included in the UN-backed Clean Development Mechanism at this stage.

That’s because too many concerns have been raised about the prospect of stored gases seeping out of their underground vaults at some stage in the future. The UN decided more work would have to be done on where liability would lie if there was seepage of gases.

The knockback for carbon capture and storage will be disappointing to energy companies exploring CCS options and investing in trials, but the decision largely mirrors the views of local scientists approached by the Science Media Centre a few month back. Here’s what they had to say on the technology:

Drs Shannon Page, Ian Mason and Arthur Williamson, Advanced Energy and Material Systems Laboratory, University of Canterbury comment:

’This paper provides a good review of the current situation regarding CCS.

’It reiterates that carbon capture offers few technical challenges but there are still serious doubts about sequestration. Nonetheless, there still has not been a demonstration of full carbon capture from an electricity generating plant.

’[In this area] the paper offers nothing new and we are concerned that the huge task of applying CCS to all existing power plants is not adequately addressed.

’Papers of this kind tend to imply that there is no alternative option. However, estimates by the US DOE indicate that renewables could supply up to four times current US electricity consumption within a shorter timeframe than envisaged for CCS. Our own work shows that New Zealand could easily have a 100% renewable electricity supply.

’The huge amount of money allocated to developing CCS would in our opinion be more fruitfully employed were it diverted to the implementation of already proven renewable technologies.’

Dr Martin Manning, NZ Climate Change Research Institute, VUW comments:

’Carbon capture and storage (CCS) from coal or gas fired power plants is now widely seen as essential if the world is to be able to keep global warming to 2°C while continuing its economic and social development.

’But the relevance of this emerging technology varies considerably by country.
The detailed summary by Stuart Haszeldine covers the status of the technology and shows that it can be a very significant development for climate change. It also points to initial projects in countries such as Australia that are showing positive results.

’At a climate change meeting in Wyoming in 2007, Fred Palmer, a senior representative of the coal industry, admitted that rapid movement into CCS was now expected to gain a high priority in the USA, China and elsewhere.

’But the importance of this technology for keeping global warming to 2°C, which is rather blandly supported by many countries, is often overlooked. The detailed greenhouse gas emission scenarios for the rest of this century, that are consistent with such a limit, involve rapid deployment of CCS but then a shift to biological fuels and still burying the carbon after burning those.
This leads to a net removal of CO2 from the atmosphere through plants combined with the capture and storage of carbon. While some scientists do suggest other ways of achieving such a net removal in future, this one directly linked to CCS has the greatest confidence so far.

’Haszeldine’s review covers what is widely regarded as a very important part of global technology for keeping to the 2°C warming limit. But in New Zealand we have the benefit of other natural sources for energy generation which can be aligned with the climate target and at lower costs for us.’

Dr Murray McCready, Research Scientist at CRL Energy Ltd.:

’This paper provides a high level review of CCS as a means to reduce carbon emissions with a focus on existing technologies and demonstration projects. The author points out that the ultimate barriers to implementation of CCS technologies are likely to be due to political and commercial factors rather than technical limitations. The technical coverage is general and while it provides a useful introduction some technologies such as oxygen transfer membranes are not mentioned. Of particular interest in the New Zealand context are points made about how CCS equipped thermal generation may respond on an electricity grid with high renewable generation. This indicates an important area for research into CCS in New Zealand.’

Ralph Chapman, Director of Environmental Studies, VUW, comments:

’I doubt if NZ will be making use of CCS unless and until it becomes very well established, and costs fall sharply. It seems likely that CCS’s costs per tonne of CO2 avoided would be way higher than abatement via other means such as renewables (displacing fossil generation), reducing transport emissions, nitrous oxide emission reduction etc.’

Dr Bob Lloyd, Director of Energy Studies Programme, University of Otago:

’The article on Carbon Capture and Storage is sub-titled How Green can Black be? The answer is: not very. The idea of clean coal is an oxymoron. The paper suggests that CCS has been on the planning boards for some time now but ’there is a lamentable lack of financial commitment’. The reason for this lack of commitment is that CCS will increase the cost of electricity generated from coal fired power stations from between 50% and 100%.

’And that increase would be uncompetitive without very large CO2 taxes. The problem is not actually financial, it is an energy problem; CCS is very energy intensive. It is likely that you would need to build close to an extra power station of roughly the same size to store the CO2 from an existing station. This progression is clearly not going to work. The article in Science also claims that if it did ever get working that it has the potential to reduce carbon emissions by 20%. But this percentage is not nearly enough.

’The latest figures suggest we should be reducing the CO2 in the atmosphere to 350 ppm. However, the existing level is around 387 ppm which means we have to virtually remove 100% of all further energy emissions of CO2 very soon. The US climate scientist Jim Hanson has calculated that we will have to eliminate all (100%) of coal fired power stations by 2030 if we are to have a fighting chance of stopping runaway climate change. Even then CO2 levels don’t get back to 350 ppm until the end of this century! Unfortunately the world is holding out for a technical fix that is unlikely to eventuate in time; trying to catch onto anything that will prevent a reduction in energy consumption and a slow up in economic growth.’

Dr Peter Read, Honorary Research Fellow, Centre for Energy Research, MasseyUniversity:

’CCS is a critical technology in mitigating climate change, given that the most effective approach — economic collapse — is unlikely to be implemented intentionally. It can cut about 80 per cent of the emissions that are inevitable from the existing and (in China particularly) growing stock of coal fired power plant.

’Co-firing with 20 per cent biomass fuel results in a zero emissions system. [This article] shows that meeting global warming limitation targets involves a steep learning curve, starting from the 36 demonstration projects in being or planned worldwide, through tens of commercial power plants in operation well before 2020 and hundreds of large plants by 2025.

’Simply pricing carbon in the market is not enough’ he states — lessons from past power plant clean-up programmes (e.g. FGD or flue gas desulphurization) show that voluntary codes do not work either. Co-operation involving world-wide information sharing needs to be enforced, with clearly signposted regulation.’

Professor Gerry Carrington, University of Otago:

’Haszeldine reviews underground CO2 sequestration technology as an advocate for the technology. He clarifies the risks surrounding the technology and highlights the uncertainty about its costs and
effectiveness. However, he does not discuss the ethical problems we will face if we ever attempt large scale application, when there will be vast opportunities for commercial gain from bad behaviour. In my view underground CO2 sequestration is only one of many possibilities for
managing the growing risk of climate change. I do not think it is so special that it should receive preference for public support.’

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