Rethinking CO2: from a waste to a resource?

Jun 8, 2016

Central to the fight against global warming is the need to reduce emissions of carbon dioxide gas (CO2). CO2 accounts for around three quarters of global greenhouse gas emissions, and annual emissions of CO2 increased by more than 42% between 1990 and 2010. Despite efforts to deploy low carbon forms of energy such as renewables, forecasts suggest that fossil fuels will still provide around 80% of total global energy supplies in 2035. For this reason, many commentators suggest that technologies which capture CO2 emissions from power stations and other sources will be essential to achieve decarbonisation goals.

Much of the discussion to date surrounding carbon capture has focused on the potential of Carbon Capture and Storage (CCS), whereby CO2 is permanently locked away in geological formations such as depleted oil and gas fields and saline aquifers.

Figure 1: Illustration of Carbon Capture and Storage scheme

illustration-of-carbon-capture-and-storage-scheme

The Committee on Climate Change  has said that “CCS is very important for reducing emissions across the economy….the cost of meeting the UK’s 2050 emissions target would double in the absence of CCS deployment.” Similarly, the International Energy Agency (IEA) has said that “there is no climate friendly scenario in the long run without CCS.” 

The UK had established a leading position in the development of CCS technology. However due to concerns over the cost of the technology the Government took a decision to cancel its £1 billion CCS commercialisation competition last Autumn, putting the future of CCS in the UK in doubt.

Alongside this, many researchers and innovative companies are looking at ways to re-use CO2 as opposed to storing it. CO2 can be used directly in a range of applications such as Enhanced Oil Recovery, food preservation, or to make decaffeinated or fizzy drinks. It can also be converted into other chemicals and products through a number of chemical, biological and mineralisation processes. In this way, CO2 can be reimagined not as a waste, but as a resource which can be used to make a wide range of useful products such as fuels, construction materials, chemicals, and plastics. These processes are variously referred to as Carbon Capture and Use/Utilisation (CCU), Carbon Dioxide Utilisation, or Carbon Recycling.

Figure 2: A Selection of Carbon Utilisation Pathways

a-selection-of-carbon-utilisation-pathways

Figure 3: Summary of CO2 Reuse Opportunities

summary-of-co2-reuse-opportunities

Yesterday, Policy Exchange held a panel debate to consider the potential of CCU technologies, involving Richard Howard (Policy Exchange), the Rt. Hon. Lord Deben (Chair of the Committee on Climate Change), Professor Peter Styring (University of Sheffield), Professor Colin Hills (University of Greenwich), and Dr Luke Warren (CEO of the Carbon Capture and Storage Association).

Lord Deben argued that the fight against climate change will require a mix of solutions and that it is very much a case of AND rather than OR. He reiterated the CCC’s position that it will be essential for the UK to deploy carbon capture and storage technologies in order to achieve decarbonisation goals. But he also said he is equally in favour of other technologies that could deliver the same ends, such as Carbon Capture and Utilisation. Related to this, he argued that there are synergies between CCS and CCU, since both technologies share a common interest in the development of more efficient and cost effective CO2 capture technologies. He criticised the Government’s decision to cancel the CCS Commercialisation programme last year, and suggested that the Government needs to set out an alternative route to delivering CCS at scale, with separate support for capture and storage, a more appropriate allocation of risk, and a strategy to develop geographical clusters of carbon capture activity.

Professor Peter Styring agreed that a new approach to carbon capture is needed, and argued that Carbon Capture and Utilisation technology could complement CO2 storage. He described how CO2 can be converted into a range of different chemicals and useful products such as synthetic fuels, Urea (which is used to make fertiliser and polymers), and construction materials (discussed further below). He highlighted an important distinction in the debate around CO2 reuse – in that some CCU technologies lock away carbon for a short period of time, whilst others lock away carbon long term. For this reason he was critical of the use of CO2 for Enhanced Oil Recovery since this merely results in the production of additional oil and gas, and associated carbon emissions. Finally, he also summarised a number of key research programmes investigating CO2 reuse, such as the £4.7 million 4CU project, and the SCOT project (Smart CO2 Transformation).But he stressed that UK spending on research and development into CCU technology is small compared to other countries such as Germany (which is spending around €400million in this field) and the US (which is spearheading the $1 billion Global CO2 Initiative and $20 million X-Prize for CO2 re-use).

Figure 4: Possible Chemical Products from CO2 Conversion

possible-chemical-products-from-co2-conversion

Professor Colin Hills described the CO2 reuse process he has developed and commercialised through a spinout company Carbon8 Aggregates. The process uses CO2 gas to treat industrial residues such as ash and produce artificial aggregates. These aggregates can be substituted for conventional aggregates and used in a range of building products – including the world’s first “carbon negative” concrete blocks. This mineralisation process only takes around 15 minutes, but mimics the carbonation processes which occur in nature over millennia to produce rocks such as limestone. The Carbon8 process is now at an early stage of commercial rollout, and the company recently built a second production facility in Avonmouth, Bristol which will be able to produce 150,000 tonnes of aggregate per year. Interestingly, at present Carbon8 has to purchase CO2 gas at a cost of around £100 per tonne, turning on its head the notion that CO2 is a waste. In fact, Proessor Hills commented that the company would be capable of utilising far more CO2 if only it was available more cheaply. This reiterates the need for further effort to reduce the cost of CO2 capture technology.

 Figure 5: Carbon8 Aggregate plant in Avonmouth

carbon8-aggregate-plant-in-avonmouth

Figure 6: Image of Carbon8 Aggregate

image-of-carbon8-aggregate

Finally, Luke Warren argued that CCU technologies appear to have significant potential, but that they are not a panacea, and should be thought of as a complement rather than an alternative to CCS. He suggested that CCU technologies are limited by scale, and would not provide sufficient decarbonisation potential in the UK on their own. He also hit on a very important point – that there is currently a lack of understanding of the economic and environmental costs and benefits of CCU technologies, which could hamper policy development.

Overall it was a fascinating and thought provoking debate. The speakers agreed that Carbon Capture and Utilisation offers significant potential to achieve decarbonisation goals and create a sustainable future for industry – but that there is a risk that the UK gets left behind in the development of these technologies. The speakers offered a number of suggestions for how policymakers could accelerate development of CCU technologies including:

Finally, Luke Warren argued that CCU technologies appear to have significant potential, but that they are not a panacea, and should be thought of as a complement rather than an alternative to CCS. He suggested that CCU technologies are limited by scale, and would not provide sufficient decarbonisation potential in the UK on their own. He also hit on a very important point – that there is currently a lack of understanding of the economic and environmental costs and benefits of CCU technologies, which could hamper policy development.

Overall it was a fascinating and thought provoking debate. The speakers agreed that Carbon Capture and Utilisation offers significant potential to achieve decarbonisation goals and create a sustainable future for industry – but that there is a risk that the UK gets left behind in the development of these technologies. The speakers offered a number of suggestions for how policymakers could accelerate development of CCU technologies including:

  • Government commitment to decarbonisation (in general) and to CCU technology specifically
  • Establishing a more robust carbon price to create a market for re-use of CO2
  • Creating a level playing field for CCU against other decarbonisation opportunities
  • More research and development funding for CCU technologies, in particular to drive down the cost of carbon capture
  • More work to increase public acceptance of carbon capture and utilisation / storage

A video and transcript is available here.

Download slides from the event.

Author

Richard Howard

Richard Howard
Director of Development & Head of Environment & Energy Read Full Bio

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