Could Carbon Storage and Usage help the UK reduce its emissions?

by Dr Kieran Brophy

02 August 2019

The UK has committed to be carbon neutral by 2050, however fossil fuels will remain important to the economy for some time.

As a signatory to the 2015 Paris Climate Change Agreement, the UK has committed to an ambitious transformation of its economy. Although decarbonising the UK’s economy must be a priority, fossil fuels will remain important to the economy.

Carbon capture and utilisation (CCU) is the process of capturing atmospheric carbon dioxide (CO₂) to be recycled for further use. CCU may offer a response to the global challenge of significantly reducing greenhouse gas emissions from major industrial emitters.

The Institute for Molecular Science and Engineering has produced a Briefing Paper that assess the economic and environmental value of CCU in the UK. The paper seeks to advice policy makers and industry on which CCU options are currently feasible for the UK.

CCU differs from the more established technology of Carbon Capture and Storage (CCS) - the process by which captured CO₂ is put into permanent storage - as it aims to convert the captured carbon dioxide to useful substances or products. This has the result of decreasing the CO₂ emissions associated with the production of, for example, plastics, concrete and biofuels.

The event was attended by academics, industry and NGOs.

At the Briefing Paper's launch, lead author Dr Anna Hankin, and Professor Nilay Shah introduced the concept of CCU along with the possible solutions available to the UK at present.

The viability of three CCU solutions were investigated: 1. the production of polyurethane (plastic), 2. carbon nanotubes (a high value form of carbon, added to materials to improve various properties), and 3. methanol (a fuel and commodity chemical).

Using captured carbon to produce polyurethane is promising

Of the three CCU solutions considered, the production of polyurethane was found to be the most promising for the UK at present.

CCU cannot provide the emission mitigation rate of carbon capture and storage, but as the UK’s entire geological storage capacity is offshore, CCU could help reduce emissions from large inland point source emitters in the short term. Dr Anna Hankin Lead author

The paper's findings suggests that producing polyurethane from captured carbon could provide an immediate short-term reduction in greenhouse gas (GHG) emissions. It works by cleaning and compressing the captured CO₂ before it is converted by chemical reactions into a form of plastic.

At present however, neither methanol or carbon nanotube production appear to be a viable solutions. This is because methanol from captured CO₂ requires a large amount of electrical energy to convert CO₂ into methanol. This would result in more GHG emissions over the entire life cycle of methanol production.

For carbon nanotubes, the amount produced from a single large point source would be equivalent to 40-50 times the global consumption rate. Therefore the paper concludes that it is hard to justify capturing large amounts of CO₂ to produce carbon nanotubes at present. However, with the increase in nanotubes used to reinforce concrete and electrical batteries, this option could be viable in the near future.

The Briefing Paper stresses that proposed CCU solutions should always be assessed always on a case-by-case basis, using detailed, UK-centric, cradle-to-grave life cycle analyses.

The full Briefing Paper can be read here.

IMSE's Briefing Paper series

The IMSE briefing paper series highlights the power of an integrated molecular science and engineering framework for addressing many global grand challenges. These papers are circulated to funding agencies, policy makers and potential commercial partners to inform debate on a range of topics. They also act to advertise the accessibility of Imperial’s world-class expertise, facilities and insight.

More information and a link to other Briefing Papers in the series can be found here.