What is Carbon Capture, Utilisation and Storage and how does it work? What sectors does it apply to and is it already operating around the world today? What role does CCUS play in meeting climate goals? Find out answers to these questions and more in our Frequently Asked Questions.

What is Carbon Capture Utilisation and Storage (CCUS)?

CCS or CCUS, stands for Carbon Capture, Utilisation and Storage. This is a low carbon technology which captures carbon dioxide (CO₂) emissions from industrial facilities such as power generation, iron & steel, fertilizer, cement, chemicals and refining and transports it by either pipeline or ship for utilisation or safe and permanent underground storage, preventing it from entering the atmosphere.

How does CCUS work?

There are three stages to CCUS: capture, transport, and utilisation or safe storage.

  1. Capture ‐ First, the CO₂ is captured at the emitting source and removed. There are three types of capture: post‐combustion, pre‐ combustion and oxyfuel combustion.  These capture methods can capture more than 95% of CO₂
  2. Transport ‐ The CO₂ is then compressed and transported to a suitable storage site or utilisation plant. Transport is generally carried out via pipelines and ship.
  3. Utilisation/Storage ‐ The CO₂ is either utilised as part of a product or injected into a suitable storage site deep under the seabed (between 0.8 – 3km down). The storage site is a carefully selected geological formation that ensures safe and permanent storage. Storage can either take place in depleted oil & gas fields, or deep saline formations.
When will the first UK CCUS plants be ready?

The UK government have committed to supporting the deployment of two CCUS industrial clusters by mid-2020 with a further two clusters to be operational by 2030, with a target of capturing 10Mt CO₂ per year by 2030.

What is Utilisation in CCUS?

Carbon Capture and Utilisation uses the same capture processes as CCS except that the captured CO₂ is then utilised in products rather than stored underground. For example, CO₂ can be utilised in cement manufacturing, where the CO₂ is pumped into a cement mix and solidifies into a hard carbonate mineral, preventing it from entering the atmosphere. Other examples of CO₂ utilisation include synthetic fuels, the food and beverage industry, dry ice industry and for enhanced oil recovery.

Whilst CO₂ utilisation should be encouraged where possible, it will only be able to reduce a small proportion of the CO₂ reductions required to meet net zero and therefore the predominant focus should be on permanent CO₂ storage.

What are Greenhouse Gas Removal (GGR) technologies and how do they work?

Greenhouse gas removal technologies focus on removing carbon dioxide from the atmosphere or through biomass, rather than from an industrial emitting source. Examples of such technologies are Direct Air Carbon Capture with Storage (DACS) and Bioenergy with Carbon Capture and Storage (BECCS).

DACS: This technology removes CO₂ directly from the atmosphere with geological storage deep underground.

BECCS: This is the process of capturing and permanently storing CO₂ captured from the combustion of biomass (such as sustainable wood chips and plant matter), for renewable energy generation. Plants absorb CO₂ from the atmosphere during growth, when we capture this CO₂ at the biomass power plant the result is a negative amount of emissions – i.e. CO₂ emissions have been removed from the atmosphere.

The Climate Change Committee’s Sixth Carbon Budget states that “Engineered greenhouse gas removals, such as Bioenergy with carbon capture and storage (BECCS), Direct Air Capture of CO₂ with storage (DACS) and increased use of Wood in Construction will be required to permanently remove carbon from the atmosphere, in order to offset remaining residual emissions in the UK and achieve Net Zero by 2050”.

How will CCUS help us tackle climate change?

The Climate Change Committee’s Sixth Carbon Budget concludes that “CCUS is essential to achieving Net Zero, at lowest cost, in the UK” and that scenarios where CCUS is excluded or minimised are “likely to significantly increase cumulative emissions over the period to 2050.”

  • It is the only technology that can significantly decarbonise industries such as iron & steel, fertilizer, cement and chemicals, enabling the production of clean products
  • CCUS provides a source of flexible, low-carbon power generation which will make an important contribution to a resilient net zero electricity mix
  • CCUS represents one of the main routes for producing low-carbon hydrogen, which can be used to decarbonise domestic and industrial heating, as well as transport
  • For those sectors that will be harder to decarbonise (such as aviation), CCUS also unlocks a key method of greenhouse gas removal, which will be critical to meet climate goals
Can CCUS only be applied to fossil fuel electricity?

No, CCUS is necessary to decarbonise many vital sectors beyond fossil fuel electricity, such as iron & steel, fertilizer, cement, chemicals and energy from waste. It has an important role to play in decarbonising industry; opening the door for low-carbon hydrogen and unlocking greenhouse gas removals, ensuring that net zero can be achieved across the entire UK economy.

Are the majority of CCUS projects around the world linked to Enhanced Oil Recovery?

No, current CCUS projects under development in the UK and Europe are not linked to Enhanced Oil Recovery. The IEA (International Energy Agency) state that “Less than half of planned CCUS facilities are linked to EOR, with a shift towards dedicated CO2 storage options.”

CCUS is too expensive, should we focus on cheaper alternatives to meet our climate goals?

CCUS is already cost-effective, and we urgently need to build the first projects, to deliver innovations and further cost reductions. Tackling climate change is an enormous challenge and we will need all low-carbon technologies at our disposal.

The International Energy Agency has estimated that by 2050, the cost of tackling climate change without CCUS could be 70% higher. They also estimate that to reach a 50% cut in global CO₂ emissions by 2050 (widely believed to be equivalent to limiting the increase in global temperature to 1.5 degrees), CCS will need to contribute nearly one fifth of emissions reductions – across both power and industrial sectors.

Is CCUS is a proven viable technology?

Yes, CCUS is a well-established proven technology with more than 25 years of demonstration in successful CO₂ storage operations. Globally, CCUS deployment has more than doubled over the last decade.

How much experience does industry have in storing CO₂?

Industry has many years’ experience of transporting and storing CO₂. The Sleipner CO₂ storage project in Norway was established in 1996 and is one of the world’s first projects dedicated solely to large scale CO₂ capture and permanent storage. The Sleipner project has now safely and permanently stored more than 20 MtCO₂ and continues to sequester over 1 million tonnes of CO₂ each year in a deep saline formation under the Norwegian North Sea.

How many projects are there in operation around the world?

The Global CCS institute report that there are currently 27 operational CCUS facilities worldwide. These are located in the USA, China, Australia, the Middle East, Canada and Europe with operations spanning a variety of sectors from Iron and Steel industries to ethanol bioenergy plants.

Even if CCUS can be proven at scale, will there continue to be residual carbon dioxide?

There have been many developments in research related to enhancing capture technologies and a capture rate of more than 95% of CO₂ emissions is now achievable.

Greenhouse gas removal technologies such as BECCS and DACS will be essential to further remove residual emissions from the atmosphere and help to limit the increase in global temperature to 1.5 degrees.

What is the difference between blue and green hydrogen?

Blue hydrogen is formed from natural gas where the CO₂ emissions resulting from breaking apart hydrocarbons are captured and stored, whereas green hydrogen uses renewable energy to split water into hydrogen and oxygen in a process known as electrolysis.

Why do we need a hydrogen supply?

The Committee on Climate Change has stated in its Net Zero Report that in order for the UK to meet its net zero climate goals by 2050, we will need 270TWh of hydrogen supply.

Hydrogen is an important fuel to help decarbonise vital UK sectors such as heat, power and transport.

Does using hydrogen emit CO₂ emissions?

Combustion of hydrogen to create energy produces water as a by-product. It does not produce carbon dioxide (CO₂) emissions.

Is CCUS safe? What if the carbon dioxide leaks out from storage?

CO₂ is stored safely offshore deep underground, between 0.8 – 3km down, for thousands of years.

CO₂ storage sites are carefully chosen to ensure the highest confidence in permanent storage and there is rigorous site characterisation, monitoring and verification procedures in place to ensure the CO₂ stays safely stored. These assessments and procedures are required by CCUS regulations before a project is allowed to proceed.

Many of the potential storage site opportunities are large saline aquifers or depleted oil and gas fields which are well understood and have already stored gas and CO₂ naturally for millions of years.

Is transportation of CO₂ safe?

Yes, in fact carbon dioxide is already regularly transported worldwide. The main options for transportation are by pipeline, ship, truck or rail.  Transport by pipeline is currently the cheapest option and has been in practise for many years both on and offshore. For example in the United States alone there are some 8,000km of pipelines actively transporting CO₂ today (Global CCS Institute).

CO₂ transport systems are monitored electronically and manually with rigorous monitoring standards, so that if there was a drop in CO₂ pressure the transport mechanism would be safely shut down.

The UK has a wealth of experience, based on designing, constructing and operating 6800km of high-pressure gas pipelines, for which it has earned a global reputation for safety.  The Code of Practice for pipelines to transport CO₂ streams are recognised as being the most cautious in the world, and the design and operation receives detailed scrutiny from the Health and Safety Executive.