Monday, May 31, 2010

Carbon Capture and Storage Not An Environmental Cure All Says Dutch Researcher

CO2 capture, transport and storage, also referred to as CCS, may well play an important role in reducing emissions of the greenhouse gas CO2, however, it should not be viewed as the answer to all environmental problems. CCS can actually contribute to other environmental problems, depending on the technology used. These are some of the conclusions of the PhD research conducted by Joris Koornneef at Utrecht University. His dissertation describes the effects of CCS on the environment, health and safety.  

It has been established with a high degree of certainty that greenhouse gas emissions from human activities are the cause of climate change. To limit this effect, emissions of greenhouse gases, including CO2, must be kept to a minimum wherever possible. One tool to achieve this is CCS, which entails the capture of greenhouse gases at sources such as power stations, followed by the compression, transport and underground storage of the gasses. “Before CCS can be carried out on a large scale, it must be clear how it will affect the environment, public health and safety” asserts Koornneef, whose research included an analysis of the total environmental impact of CCS and the risks of transporting CO2 by pipeline.

Total environmental impact of CCS
As part of the life-cycle analysis, Koornneef assessed the environmental impact of the entire chain for coal fired power stations involving CCS – from the coal mine to the generation of electricity. He then looked at the impact on various environmental problems. “CCS substantially reduces the contribution to the greenhouse effect,” says Koornneef. “CCS can also be beneficial at a more localized level, by significantly reducing emissions of fine particulate matter and sulfur dioxide, for example.

However, additional energy is required for the capture, transport and storage of CO2.” Koornneef demonstrates that the use of post-combustion - a particular method of CO2 capture - at coal fired power stations, will lead to increased acidification and nitrogen pollution. It also contributes to other environmental problems, such as resource depletion and the destruction of the ozone layer. Selecting the right technology and improving existing technology will greatly affect the total environmental impact of CCS.

CO2 transport by pipeline
Koornneef also studied the uncertain factors in the risk analysis of CO2 transport by pipeline. This is an important aspect in the public debate on the safety of CO2 storage near Barendrecht in the Netherlands. According to Koornneef, the existing models have not been tested for high pressure CO2 release and dispersion. “However, that’s not to say that CO2 pipelines are unsafe. It looks as if the risks can be mitigated quite effectively with current technology, such as safety valves,” says Koornneef.

CO2 capture risk studies
Finally, Koornneef also researched the risk studies associated with CO2 storage projects, concluding that accurate calculation of the risks is not currently possible. However, this does not mean that we lack the knowledge to assess whether underground storage can be performed safely. Koornneef believes it is highly unlikely that CO2 will escape and have negative effects on the environment or public health. Nonetheless, it is important that storage projects be monitored in order to establish more precisely how CO2 behaves when stored underground, for instance.

This study was conducted within the context of the Dutch research program CATO (which stands for CO2 capture, transport and storage), which took place from 2005 to 2009. Funded partly by the government, this research program was a consortium of businesses, universities (including Utrecht University), research institutes and interest groups. In 2009, the research was continued with the launch of the CATO-2 program.

The Dutch government has decided to start two large scale CCS demonstration projects in 2015. CATO-2 is the Dutch national CCS program. It includes a consortium of nearly 40 partners working together to help realise the governments plans. CATO-2 has an extensive budget and is expected to be running from 2009 until 2014. This budget is provided by the Dutch government and CATO consortium partners.

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