If cutting greenhouse gas emissions is as important as is claimed, there are two main ways to do it: stop using fossil fuels as soon as possible, or continue to burn them while viable alternative energy sources are developed, and remove and lock up the resulting carbon dioxide. Carbon Capture and Storage (CCS) still has its supporters, despite a singular failure to upscale in any way that could be easily rolled out on the vast scale needed. But, if – and it’s a big if – a recent report is true, then this outlook could change.
The report on the Independent website certainly hypes up one particular approach – Clean coal: Firm claims world’s first commercially viable, zero-carbon power plant is a ‘game changer’. According to this, the company boss has even suggested the inventor should get a Nobel Prize. In a world where Bob Dylan can get the Literature prize (it will be interesting to see what his Bobness has to say about that) and the IPCC and Al Gore can share the Peace prize, perhaps this is not such an outlandish suggestion.
The conceptual beauty of CCS is that we could, in principle, continue to rely on proven and reliable fossil fuel power stations for decades to come, while slashing carbon dioxide emissions. Indeed, many projections of the path to be taken to mitigate temperature rises (predicated, we have to remember, on the credibility of the enhanced greenhouse hypothesis) assume that CCS will be an essential tool not only to cut emissions but to remove some of the CO2 already in the atmosphere. Viable carbon capture and storage would allow us to have our cake and eat it. If it could be done at an acceptable cost, it could be a big part of a ‘least regrets’ policy.
The technology referred to in the article comes from Carbon Clean Solutions Limited (CCSL) an Anglo-Indian outfit that has received over £4 million of UK government funding for their research. According to the report “CCSL says it developed a new solvent that makes the carbon capture process up to 66 per cent cheaper than traditional methods, costing $30 per tonne of carbon compared to $60 to $90.”
Normally, flue gases are passed through a solution of amines to remove carbon dioxide. However, the company seems unwilling to say any more about the nature of its new ‘solvent’ (branded as CDRMax), despite mentioning patent protection. Also, although the claim is for a commercially-viable technology, it is being used only in a 10 MW power station in Chennai, tiny by comparison with the more typical station generating around a gigawatt.
In fact, the capturing part of the process is the relatively easy part (although it has to be acknowledged that any cost-saving is to be welcomed). Developing some kind of standardised system to treat flue gases would be well within the capabilities of engineers. What is really challenging is what to do with the captured CO2. A quick Google search reveals estimates of about 300 tonnes of carbon dioxide produced per GWh of energy generated. For a plant operating at, say 75% capacity over a full year, that’s roughly two million tonnes of CO2 from a single power station. Since there are thousands of such stations, the scale of the problem becomes apparent.
In demonstration projects to date, the captured carbon dioxide is released from the sequestering agent (which is reused), compressed and piped to somewhere where it can be injected underground into, for example, depleted oil fields. Every scheme will be different, so there will be no economies of scale, and the long-term security of such underground stores is unproven. It is this aspect that makes talk of CCS playing a big role in a decade or so wildly optimistic. For a topical discussion of the issue, based on Donald Trump’s assertions about the potential for ‘clean coal’, see Clean Coal: Fact or Fiction?.
This is why the second aspect of the operation of the plant in Chennai is potentially far more important: “While carbon capture has been associated with storing carbon – for example by returning it to coal mines – the material taken out of the Chennai plants emissions is made into soda ash, then sold to make a range of products from detergents to glass.”
Again, unfortunately there is no detail about how this will be done, but it could present a major step forward. The article talks about value-added use of the soda ash – or sodium carbonate, as it is more commonly known – but even if most of it goes to waste, it is a solid, which is much easier to handle than compressed gas. The remaining problem is that it is also water soluble, so cannot simply be buried. But going a step further and converting it into an insoluble salt could be the answer to long-term storage. After all, vast quantities of CO2 are currently tied up in the form of carbonate rocks.
Of course, all this may be immaterial if the rise in average temperatures projected by the IPCC continues to be much higher than reality. We are getting close to two decades in which temperatures have barely changed, with the exception of periods in which there are El Niño events, such as the one we are just emerging from. If this trend continues as CO2 levels continue to rise, there must surely be some serious questioning of policy.
In the meantime, this uncertainty both about future climate change and the technology available to cope with it reinforces the case for more R&D in a wide range of potentially useful areas of technology, including CCS. This apparently successful new development may turn out to be over-hyped, but sooner or later there will be one or more disruptive technologies that emerge to change our thinking in terms of energy and climate change.
These may be in CCS, but could just as easily be in energy generation, storage or use. Whatever their nature, they could make all questions of policy and subsidy irrelevant. If there is something economic that is better than the current system, there will be plenty of people eager to exploit it.
Martin Livermore
The Scientific Alliance
St John’s Innovation Centre
Cowley Road
Cambridge CB4 0WS
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