Carbon Sequestration: Is a New Method Ready to Rock?

It seems that summer has finally arrived. The sun is shining, the birds are singing and an international football tournament (which England are 99% certain to win) is about to begin. But today's post is not about any of those things. Rather it concerns interesting new research that suggests sequestering atmospheric carbon dioxide by injecting it into basaltic rock may be a "climate change breakthrough". But how? And why?

What is carbon sequestration?

Carbon sequestration involves capturing atmospheric carbon dioxide and finding a way to store it for long periods of time. It's an active area of research to try and combat anthropogenic climate change, which is being fueled by the enhanced greenhouse effect. The UN Intergovernmental Panel on Climate Change have stated that carbon capture and storage is "hugely important to tackling climate change in the most cost-effective way".

Carbon dioxide is captured naturally from the atmosphere via chemical, biological or physical processes, but artificial processes have also been devised to achieve a similar goal including sequestering carbon dioxide in ocean water, reservoirs and aging oil fields.

Schematic showing both terrestrial and geological sequestration of carbon dioxide from a coal-fired power plant.

What is the new technique? 

The new technique involves pumping carbon dioxide underground and turning it rapidly into stone. Pumping carbon dioxide into volcanic rocks which underlay Iceland accelerated a natural process in which basalts react with carbon dioxide to form the carbonate minerals that comprise limestone. The researchers expected it take possibly thousands of years for the carbon dioxide to turn into stone, but they were stunned to discover that it only took two years. .

Basalt: a lump of rock with more uses than being a pet?

What are the benefits of the new technique...?

In the conventional carbon capture and storage process outlined at the start of this piece, the carbon dioxide stored in old oil fields could potentially leak as there are no rocks present which could mineralise the carbon dioxide into stone. Because of this leakage potential, the stores have to be monitored, adding to the cost of the process. Additionally, in the Netherlands and Germany, conventional carbon capture and storage has been supsneded due to concerns over earth tremors. 

The new method promises a cheaper and more secure way of burying carbon dioxide, produced from fossil fuel burning, underground. Juerg Matter, the lead author of the research which has been published in Science, has said that turning carbon dioxide into stone is the "ultimate permanent storage". Furthermore, the conventional methods necessitate the carbon dioxide to be removed the mixture of gases in emissions, an expensive process which is not required in the new procedure.

...and what are the potential stumbling blocks?

Water. The process is a thirsty one, requiring 25 tonnes of water for each tonne of carbon dioxide buried. However, this could be overcome by using seawater if the process were to be carried out at coastal sites. A second concern is that subterranean microbes could break down the carbonate into methane, a much more powerful greenhouse gas than carbon dioxide. However, there is no evidence of this occurring from the initial research in Iceland.

Sea you soon? With a lotta water needed coasts may be the ideal place for new carbon storage.

What can we expect in the future?

The initial Iceland research project is being scaled up with the aim of burying 10,000 tonnes of carbon dioxide a year. There is also great potential for this sequestration process to take place in other parts of the world, as the basalt rocks can be found commonly on the floors of all the oceans and under parts of other land masses.  Testing has been taking place at the Columbia River Basalts in Washington and Oregon in the U.S.A. and Martin Stute of Columbia University has said that this sequestration process could be used for "power plants in places where there's a lot of basalt". Columbia University are also investigating a rock type in Oman, which may be even more effective at turning carbon dioxide into basalt.

So, the future for carbon storage is bright, right?

Well, yes and no. On the research covered here, Professor Stuart Haszeldine of the University of Edinburgh has described the new method as "terrific" and that it "may well provide a low-cost and very secure remedy...where suitable rocks exist" but also stressing that "this needs to be used as well as all the existing propositions...no single remedy is anywhere near big enough or fast enough".

Other methods are indeed being developed. For example, ExxonMobil are supporting a project which utilises fuel cells to make capturing carbon dioxide cheaper and Ford have been using carbon dioxide to make foam, which they are using in the vehicle production.

But it's not all good news. Globally, carbon capyure and storage has not developed as quickly as was jope, and at the end of last year, the UK government cancelled a £1billion competition for carbon capture and storage technology, despite promising it in their general election manifesto. Who ever would have expected that...?

Thumbs up if you broke your promise Dave

Til next time

Rob

Find out more about the CarbFix project here: https://www.or.is/english/carbfix-project