Taking Carbon Capture and Storage from the lab to reality

Professor Andy Mitchell was the Lead Principal Investigator of Geo-Carb-Cymru, a collection of researchers funded by the Low Carbon Energy and Environment Research Network Wales working together to reduce carbon dioxide in the atmosphere. The cluster consisted of researchers from Aberystwyth University and Cardiff University, National Museum Wales, British Geological Survey, and international partners. Discover how seed-funding led to research implementation on a commercial scale.

It’s hard to imagine, but life still continues in Earth’s most extreme environments.

With bacteria surviving at great pressures in ice, deep underground and far underwater, how can we utilise their extraordinary abilities for our own benefit?

Andy Mitchell and his colleagues at Aberystwyth University and beyond have been delving into the subject, using what we know about these ‘extremophiles’ to deduce engineered solutions to problems that our society is facing.

The initial focus of the Geo-Carb-Cymru Cluster, formed by under the first phase of the research network, was two-fold; how can we use microbes to help us capture and store carbon to prevent climate change, and how can we exploit Wales’ plentiful disused mines to tap into a low-carbon energy source.

Both streams of work have been very successful, leading to continued research outputs alongside expertise and real-world applications.

Here, we’re going to dive a little deeper into the idea of geologic carbon capture and storage.

The phrase ‘carbon capture and storage’ is wide-reaching. From the carbon captured from the air by plants and stored in their structures, to actively capturing the carbon emissions from industry to be stored in deep underground. Whatever the method, scientists agree that carbon capture and storage (CCS) is vital in our efforts to first halt, and then reverse, our carbon emissions.

Geologic CCS in particular involves pumping pressurised carbon dioxide deep underground as a way of preventing it adding to atmospheric pollution. It’s thought that this alone could reduce global carbon emissions by 19%.

Andy and his team wanted to explore the potential for deploying the solution in Wales.

By creating high-resolution 3D maps of the deep rock structures beneath the seabed around Wales, the team was able to identify the eastern Irish Sea as a region of particular suitability; offering a low-risk location which could offer 10% of the UK’s underground carbon storage potential.

Another key aspect of the work was to assess the role of microbes in helping to stabilise stored carbon at these depths.

The particular microbe under the microscope in this case, was Sporosarcina pasteurii, a naturally occurring soil bacteria                                                       that produces hard calcium carbonate as a by-product of their own energy production technique.

If these carbonate-forming bacteria could be injected underground with the captured carbon dioxide, could they turn CO2 into a solid?

Taking advantage of advanced data processors and microbial genetic information, Andy and his team were able to develop new models to assess just this. The models considered thermal, hydraulic, chemical, gas and mechanical activity as well as microbial interactions with other cells, and from rock pores to entire rock formations.

The carbonates formed by the bacteria act as an adhesive between tiny pores.

Utilising the soil microbes to make underground ‘cement’ was shown as an effective method to seal fissures which may occur during the CCS process (fissures being potential means for the gases to escape back into the atmosphere, reducing the efficiency of the approach to combat emissions).

After extensive modelling and experiments in the laboratory, the Geo-Carbon-Cymru team worked with partners at Montana State University in the United States and were able to take the work from lab to field-scale with real-life demonstrations taking place in Alabama in 2019.

With results showing that the Sporosarcina pasteurii sealed underground fissures more effectively than any traditional engineering technology to date, the concept was quickly put into commercial use in the United States.

Back in the UK and we are seeing the implementation of four new carbon storage hubs, one of which is located in the North-west of England and North Wales, which will see CCS take place in the eastern Irish Sea off Liverpool.

“Our work, in collaboration with the British Geological Survey, has helped to identify and assess carbon storage capacity in Liverpool Bay. Whilst there were many other research activities that contributed to the new carbon storage hubs, our modelling helped lay the path for this emissions-reducing initiative”

Andy Mitchell

And this is just one stream of success that has arisen from funding administered by the research network. Andy believes that the people and expertise amassed during the initial phases of both the CCS project and its’ counterpart assessing disused mines for groundwater heating, enabled the research team to reach the critical mass of resources for being the go-to academics for microbial geochemical reactions in extreme environments.

You’ll now find Andy and his colleagues on frosty ice-sheets as well as exploring the depth beneath our feet as they continue the quest to discover life that harbours the answers to many of our questions.

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