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What is carbon capture and storage (CCS)?

The UK is on a journey to achieving net zero emissions by 2050 and here at National Grid ESO we have our own ambition to be able to operate the electricity system with zero carbon by 2025.

But there are many different sectors and industries in Britain and not everyone can reduce their carbon emissions to zero by 2050.

The aviation and agriculture industries for example are likely to be emitting carbon from their activity three decades from now. So, for those who want to do more, generating negative emissions, or offsetting emissions, is the answer.  

The power sector is ideally placed to help with this, using carbon capture and storage (CCS) in technologies like Direct Air Capture and Storage (DACCS) and Bioenergy with Carbon Capture and Storage (BECCS) to produce negative emissions.

What is carbon capture and storage (CCS)?

Carbon capture and storage (CCS) is a range of technologies that hold the promise of trapping around 90% of the carbon dioxide emissions from power stations and industrial sites.

It involves collecting, transporting and then burying the CO2 so that it does not escape into the atmosphere and contribute to climate change. Sometimes the carbon is actually used in other industries or processes, which is referred to as Carbon Capture Usage and Storage (CCUS).

CCS is a three-step process involving:

  1. Capture: CO2 is separated from other gases produced in industrial processes, for example at a coal-fired power plant or a steelworks.

  2. Transport: the CO2 is then compressed and transported via pipelines, road transport or ships to a site for storage, or for use in another industry.

  3. Storage: finally, the CO2 is injected into rock formations deep underground for permanent storage.

Where is the carbon stored?

Typically, it needs to be 1km or more underground. One site that’s been in the news recently is the proposed Zero Carbon Humber project. It’s a saline aquifer named ‘Endurance’, which is located in the southern North Sea, around 90km offshore. Endurance is approximately 1.6km below the seabed and has the potential to store very large amounts of CO2.

Can CCUS help achieve negative emissions?

Yes. It means more carbon is removed from the atmosphere and stored then is emitted. So overall, emissions are negative.

How critical is carbon capture in helping us get to net zero?

Combined with bioenergy (BECCS) it has a critical role to play in decarbonisation. BECCS features prominently in three of the four scenarios modelled in our Future Energy Scenarios 2021, generating up to 68 MtCO2e of negative emissions by 2050 – and in those three scenarios Britain reaches its net zero target.

But there’s one inescapable finding: while nature-based solutions like tree planting play a key role, net zero currently only seems possible with the negative emissions that technologies like BECCS and DACCS can deliver and both rely on forms of CCS.

CCS and BECCS can’t deliver all the net negative emissions Britain needs, though. In the energy sector, other low and zero carbon sources of energy, the deployment of hydrogen, and the scaling up non-traditional sources of flexibility such as demand side response and storage also have key roles to play.

Whatever the outcome 30 years from now, it will have taken a whole system approach to get there – with different aspects of our energy industry contributing in different ways to meet Britain’s 2050 target.

What is Bioenergy with Carbon Capture and Storage (BECCS)?

Another way we can generate negative emissions is by using Carbon Capture and Storage (CCUS) in conjunction with Bioenergy (BECCS).

For example, electricity generated by burning organic matter (biomass), rather than coal or gas, with carbon dioxide (CO2) emissions captured using CCUS, will result in negative emissions.

‘Negative emissions’ is the term given to the removal of greenhouse gases from the atmosphere. This can be done naturally, like by planting trees which pull CO2 out of the atmosphere via photosynthesis and store it in forests, vegetation and soil.

Our latest Future Energy Scenarios, which outline four different, credible pathways for the future of energy between now and 2050, show that whilst natural options feature heavily, BECCS is the largest provider of negative emissions in all scenarios that reach net zero – so long as feedstocks are sustainable and land is used sensibly.