The role of carbon capture and storage (CCS) in Net Zero
Carbon capture remains a significant risk to the UK reaching Net Zero on target
Net Zero is reliant on large-scale carbon capture and storage (CCS) as it is critical to the success of other key elements in the system: to capture the CO2 produced in the proposed large-scale hydrogen production via steam methane reforming; to enable firm, low-carbon power generation using Combined Cycle Gas Turbines (CCGT) and bioenergy; and in the decarbonisation of CO2-emitting industrial processes.
CCS systems will need to capture, transport and store up to 176 MtCO2 per year by 2050. In addition to CCS, Net Zero proposes carbon capture through afforestation of around 30,000 hectares per year, increasing woodland cover of the UK’s land area from 13% to 17%.
- Up to 176Mt/yr of CCS envisioned – 4x today’s global capacity.
- 40% of our energy will be dependent on CCS.
- ‘Clusters’ of multiple and diverse CO2 sources sharing infrastructure (e.g. CCGT with CCS for electricity production, industrial plants with CCS, hydrogen production) will need to be developed, as no such clusters with end-to-end CO2 management and CCS exist today.
CCS has the potential to manage CO2 from almost any source and offers a route to negative emissions (removing CO2 from the atmosphere) through bioenergy with CCS.
CCS is a proven technology, that has been used in heavy industry and the oil and gas sector for decades, however, it has yet to be deployed on an industrial level in the UK and total global capacity is currently only 40Mt/yr, mostly from projects that utilise CO2 from a single source for the purposes of oil recovery. The Net Zero scenario envisages the UK alone capturing and storing four times that amount, from diverse sources and not always with the economic benefit that drives enhanced oil recovery.
There are three technology areas required for CCS – CO2 capture, transportation and storage.
There are three methods of CO2 capture: post-combustion, pre-combustion and oxy fuel combustion.
- Post-combustion involves scrubbing the CO2 from flue gases released during the combustion process.
- Pre-combustion uses a gasification (solid fuel) or reforming (gaseous fuel) process, followed by CO2 separation to yield a hydrogen-rich fuel gas.
- Oxy-fuel combustion involves combusting fuel in recycled fuel enriched with oxygen to produce a CO2-rich gas.
Capture processes vary from well proven with decades of experience to developmental. Given the key role CCS will play in the Net Zero scenario, we expect significant process development in the future. The concept of ‘clustering’ CO2 from multiple and varied sources implies that multiple carbon-capture technologies will be used.
The technological aspects of CO2 transport, compression, buffer storage and pipeline transport are all well understood and established technologies. The major impediment to increased CO2 transportation is the financing and contractual framework required for the increased infrastructure required.
CO2 can be permanently stored deep underground in geological formations. In the UK these are located offshore in either saline formations or depleted oil and gas reservoirs. Enough storage locations have already been identified in the UK to last approximately 100 years.
Net Zero is dependent on implementation of CCS at an unprecedented scale, requiring the UK to have 4 x the current global CCS capacity by 2050.
Whilst each of the component technologies across the CCS chain have relatively low individual technical risk, the integration and deployment timing of the CCS system is challenging. Likewise, while most CCS processes are proven, these are not currently required to operate intermittently with fast start-ups, as the CCS clusters envisioned in the UK would be required to.
There are technical issues to be overcome and complex commercial issues to be resolved, with progress in the UK to date being very slow. There is a potentially serious gap between what is described in the Net Zero system and current government policy and progress towards CCS.
Inevitably CCS adds to the cost of electricity production and no utility will deploy CCS at scale until either mandated by regulation, or until the cost of carbon emissions exceeds the cost of CCS. Yet without large-scale CCS, the cost of meeting the UK’s previous target of 80% reduction on 1990 levels by 2050 would almost double.
To date the UK has been unable to construct and commission a successful demonstration-scale CCS project. If the UK is unable to successfully deploy a CCS demonstrator by the mid-2020s and build consensus and confidence around CCS as a route to decarbonisation, there is a risk that one of the central tenets of Net Zero will be undeliverable.