Current acting Prime Minister, Mathias Cormann, has stated on Sky News (where else?) that “Carbon Capture and Storage is a proven technology which helps reduce global greenhouse gas emissions”1.
Carbon capture and storage (CCS), or carbon sequestration, as it is also known, is the process of capturing waste carbon dioxide from major sources such as coal-fired power stations, and transporting it to a storage site and usually injecting it underground into geological formations from which natural gas or petroleum have previously been extracted. Its aim is to prevent the carbon dioxide entering the atmosphere and exacerbating global warming2.
Mathias Cormann is either ignorant or is lying by omission. Most of the CCS projects currently in operation simply capture carbon dioxide from hydrocarbon production facilities, as carbon dioxide often forms a proportion of the gas produced from natural gas and oil wells. While this gas is still occasionally vented to the atmosphere, for over 30 years it has been reinjected into the wells to enhance hydrocarbon recovery from those oil and gas fields. Once the oil or gas field is exhausted, the injected carbon dioxide will remain in those geological formations, if not forever, for a very long time. However, the extra oil and gas obtained by such enhancement will inject more carbon dioxide into the atmosphere.
What many people perceive to be CCS is what is termed ‘post-combustion capture’ the extraction of carbon dioxide from the flue gases of plants such as coal-fired power stations, and this has proved to be problematic. The key challenges for the CCS industry are: its expense, and the requirement for significant funding from government; the unproven nature of the technology and the albeit slight possibility of leakage; costs of CCS mean that even coal-fired electricity from already established plants will be more expensive than wind power; the volume of carbon dioxide requiring storage is huge if it is to have any effect on the rapidly increasing concentration in the atmosphere3.
The problem with CCS is that it is costly and energy intensive. For a gas-fired power station you have to burn about 16% more gas to provide the energy for the capture. Therefore, you increase the emissions of other pollutants (e.g. sulphur dioxide, nitrogen oxides and particulates) by that 16%4.
One new technology that shows promise is what is termed oxy-fuel combustion. For this, oxygen is extracted from the air, and injected into the fossil fuel which is burnt, then using the combustion products (water and carbon dioxide) to drive high-pressure turbines and produced electricity. The hot carbon dioxide is then recycled back into the burners, thereby improving thermal efficiency. The almost pure carbon dioxide flue gas stream is at such a pressure that it can be piped to the sequestration site. This sounds great until you realise that it is not suitable for retrofitting to existing power stations4.
So, apart from being used in enhanced hydrocarbon production, where does CCS work commercially? Nowhere.
One of the cases which perhaps demonstrates the futility of CCS is that of the ROAD project in the Netherlands. It was supposed to capture 1.1 million tonnes per annum from a coal-fired power plant. However, it has been cancelled because of the likelihood that coal-fired electricity generation will cease in the Netherlands1. In Australia, 13 fossil-fuel power stations have closed over the last 5 years, keeping tens of millions of tonnes of carbon dioxide out of the atmosphere. This is a much more efficient way to decrease emissions, and it is precisely going down this ROAD (excuse pun) which will kill of most of what was hoped to be large-scale CCS from fossil fuel power plants. You have to laugh.