An industry professional explains what this much talked about technology is, what its potential benefits are and discusses the downsides.
Carbon Capture Usage and Storage — or CCUS, as it is often referred to — is increasingly being talked about as one of several new or emerging technologies which will help us to lower our carbon emissions and reach Net Zero.
The Committee on Climate Change (CCC) includes the use of carbon capture and storage as an essential part of its ‘balanced pathway’ to meeting the UK’s sixth carbon budget — a legally binding steppingstone on the pathway to Net Zero by 2050 — and the UK Government has recently announced £20 billion in funding for CCUS.
But what is CCUS?
Carbon capture can either be ‘point source capture’ or ‘direct air capture’, meaning that the carbon is either captured where it is generated (like a gas power plant) or pulled out of the atmosphere and then captured.
The exact approach to capturing carbon varies across different industries but common across all is reacting waste gas or the air with a solvent that likes to bond with carbon when heated; this means the carbon is separated out from the other gases it was mixed in with.
The bonded solvent and carbon are then cooled so that the solvent releases the carbon, leaving a pure flow of carbon dioxide. This pure flow of CO2 is then transported, either to be used (for example, in the production of carbonated drinks!) or stored. Depending on how far the carbon needs to go, and the geography of where it has been captured, transport could be via pipeline, shipping, train, or a combination of options.
Storage can also vary depending on the geography and geology of the country storing the carbon. The key aim is that the captured carbon is locked away in the ground so that it will stay there for a very long time, rather than going into the atmosphere and contributing to global warming.
In the UK, the geology of the North Sea, perhaps most known for its production of oil and gas or, more recently, wind farms, has ideal sites for the long-term storage of carbon. The plan is to pipe the captured carbon out to these sites in the North Sea, drill down about a mile below the seabed, and trap the carbon in gaps in the rock which previously held natural gas.
What are the benefits?
Point source carbon capture and storage provides a pathway to Net Zero for some industries which will find it very difficult to decarbonise, even with advances in technology. Referred to as the ‘hard to abate’ sector, this includes key industries such as cement production, which produce substantial emissions, but are hard — if not impossible — for us to stop using.
Capturing the carbon emissions from these industries allows a way for them to continue to operate but without the harmful emissions. Carbon capture and storage also allows us to continue to generate electricity from carbon-producing sources — like burning gas and waste — without continuing to emit carbon into the atmosphere. Although the longer-term aim is for our electricity generation to be dominated by renewables, paired with more extensive and sophisticated battery storage to help manage demand, fossil fuels will be needed in the mid-term as we transition our energy systems.
While point source capture avoids carbon from current and future industry being emitted into the atmosphere, decreasing the level of harmful greenhouse gas emissions we continue to produce, direct air capture pulls carbon that has already been emitted out of the atmosphere, decreasing the overall stock of carbon.
This is key, both because the level of our historic emissions has been too high — we have too much carbon already in the atmosphere — and because, even if we successfully transition our industry, economy and society to a low carbon future, it is likely that some carbon will continue to be produced and emitted. Direct air capture presents a way to counteract this, so that we can reach Net Zero.
What are the disadvantages?
Although the costs vary across industries and technologies, all carbon capture usage and storage remains an expensive solution to decarbonisation. Even for industries that have to pay a price for the carbon they emit (which is not common across all industries and varies from country to country), the cost of paying for CCUS is higher than the penalty they pay for continuing to emit.
This creates a lack of incentive for the private sector to take up CCUS, meaning that government intervention and funding is likely needed to start and scale up carbon capture and storage at the level needed to get to Net Zero. Government funding is needed across a huge range of technologies and interventions to reach Net Zero, from wind farms to insulation, so any investment in CCUS needs to be weighed up against the benefit of investing in other solutions.
If governments do invest in carbon capture and storage, it will be at the benefit of companies which have historically been the highest emitters — such as oil and gas companies, or power plants — allowing them to pivot their operations to a ‘Net Zero’ friendly approach. While some will see this as a key stepping stone in the transition to a low carbon future, others will disagree with historical emitters benefitting from the transition, particularly if funded by taxpayers’ money.