How carbon capture technologies support decarbonisation

In conversation with David Hynes at Pentair

Carbon capture utilisation and storage technologies will play a key role in reducing carbon in the atmosphere. Here, one of our Business Development Managers, Chris Negus, speaks to David Hynes from Pentair about bio-based carbon capture technologies and how they support decarbonisation.

 

Chris: Hi David, could we start with an explanation of what is meant by the terms carbon capture storage and utilisation?

David: Carbon capture and storage (CCS) is the permanent removal of carbon dioxide (CO2) from the atmosphere, or before it gets to the atmosphere, and storing it in the ground. Carbon capture and utilisation (CCU) is similar, but instead of storing the CO2 it is used in other industries, such as the food and beverage industry or to make fire extinguishers. Currently, the use of CCU is more widespread, as further developments are needed to make the storage of carbon commercially viable. Carbon capture can also be defined based on how the CO2 is being produced in the first place. For example, bio-based carbon capture refers to when the CO2 comes from a biological source, such as breakdown of organic waste in an anaerobic digester.

 

Chris: So, it is really a collection of technologies, some of which are more developed than others at this stage. How does the carbon capture process itself work?

David: Carbon capture captures CO2 which would otherwise end up in the atmosphere. In most cases, carbon capture is coupled with another process such as combustion, and the CO2 is taken from an exhaust stream. The capturing process involves use of a chemical scrubber combined with heat. The CO2 is then cooled and compressed to liquidise it, making it easier to transport and store.

 

The technology can also be coupled with other processes, such as production of cement or steel. These are carbon intensive processes which will not stop in the short or medium term, as they are needed to build infrastructure. By capturing the CO2 that would otherwise be emitted into the atmosphere, these processes can reduce their overall carbon footprint.

 

In bio-based carbon capture from biomethane production, after biogas has been upgraded to biomethane, excess CO2 is captured and liquidised for storage or use.

 

Chris: Thinking of carbon capture and utilisation, are you able to tell us more about the uses of captured CO2?

David: CO2 is used in several industries for many different purposes. This includes use in breweries, packaging meats and other perishable food products, pH balancing in wastewater treatment and dry ice production.

 

Chris: From a climate perspective, the benefits of CCS are clear, as carbon is being removed from the atmosphere and stored in the ground, effectively the reversal of using fossil fuels. Could you explain the impact of CCU on the environment?

David: Globally, 230 Mt of CO2 are used per year[1]. With CCU, the environmental benefit comes from repurposing CO2 which is otherwise going to be released straight into the atmosphere, replacing the demand for manufactured CO2.

 

Bio-based CCU coming from biogas plants has the lowest carbon intensity score compared to all other sources, partly because CO2 from anaerobic digestion is already 99% pure, so capturing it and converting it to liquid form is very efficient. The same process at a fossil fuel power plant has just 10% CO2 in the flue, so the purification process requires more energy.

In addition, the other benefits associated with biomethane production can be factored in, such as diverting food waste from landfill, replacing demand for fossil fuel derived gas and production of a nutrient-rich digestate which can be used as organic fertiliser.

 

Chris: That’s really interesting. So, what’s next for carbon technologies, and how do you see them continuing to support with decarbonisation?

David: Every new AD facility should consider incorporating a carbon capture system. The technology exists, and it even provides additional sources of income for the plant, as they could potentially sell the CO2 and also generate carbon credits to sell to businesses looking to offset emissions. Similarly, older AD plants can be retrofitted with carbon capture technology to access the same benefits.

 

In the long term, CCS will likely have an increasing role in removing carbon already circulating in the atmosphere and putting it back into the ground. We expect the storage technology to be commercially viable within the next few years.

 

Finally, it is important to note that carbon capture technologies are just part of the solution to climate change, alongside improving energy efficiency, scaling up renewable energy production and consumer decisions that prioritise the planet.

 

Chris: That brings us nicely to our final question, in which we ask all our guest speakers for their personal behavioural or lifestyle change they could make to contribute towards achieving net zero. What is your zero carbon pledge?

David: I intend to let the grass grow in my garden! By allowing small spaces to rewild carbon can be sequestered in soil, and biodiversity increases.

[1] https://www.iea.org/reports/putting-co2-to-use