7 carbon removal technologies that can help you reach Net Zero

What are CDR and CCUS?

CDR is the process of removing carbon emissions directly from the atmosphere. In contrast, CCUS captures carbon dioxide (CO₂) emitted by a smokestack or flue, transports it and stores it safely and permanently – often underground. Both approaches have the potential to help the UK reach net zero.

Nature-based CCUS

There are several nature-based approaches to removing and safely storing CO₂ and other Greenhouse Gases (GHGs).

Through growing more trees and forests

The two options below have enormous potential to remove GHGs from the atmosphere, and are relatively low-cost:

• Afforestation – planting and growing trees to create new forests.
• Reforestation – replacing forests that have already been destroyed (e.g. by wildfires) by planting new trees.

There are also several other approaches to afforestation designed to combine tree planting with farming. These include silvopasture, where trees are mixed with animal farming systems, and cropland agroforestry, where trees are grown among rows of crops.

The major challenge for these approaches is to ensure they don’t lead to deforestation in other areas. For instance, if agricultural land is taken out of use as part of an afforestation programme, then farmers are likely to need other land to grow crops, graze cattle, or use in other ways. If forests are destroyed to provide that land, there’ll be no real net gain in tree cover. In short, there needs to be a real increase in net forest sizes for afforestation or reforestation to succeed.

Blue carbon

This is carbon that’s captured in the oceans. Coastal ecosystems – including mangroves, salt marshes and sea grasses – act as a carbon sink, absorbing and storing carbon in soil.

Although these ecosystems cover less area than the world’s forests, they absorb carbon at a much faster rate, and can store it safely for an incredibly long time.

The challenge for this approach is the need to protect coastal ecosystems so they’re still there to absorb the carbon.

Technology-based removal

Technology also offers ways to remove and store CO2, including:

Biochar

Biochar is a special type of charcoal made from biomass – typically unusable wood or farm waste – burned in the absence of oxygen.

By adding biochar to soil, it’s possible to increase the amount of carbon ‘locked’ into it for hundreds or thousands of years. Biochar also helps soil retain water, improves plant growth and can even reduce methane and nitrogen emissions.

One of the challenges associated with biochar is that frequent application can lead to the compaction of the soil, which eventually reduces fertility.

Enhanced weathering

Rocks naturally absorb CO₂ as they weather and erode when it rains. This happens because carbonic acid is formed by rainfall combining with carbon dioxide as it falls. When this acid reacts with rocks and soil, it’s mineralised and chemically stores carbon emissions in the form of carbonates.

Normally, this process takes hundreds of thousands of years. Now, however, experts are working on ways to accelerate it by crushing rocks and spreading the resulting powder over farmland. This absorbs carbon dioxide and locks it away permanently.

Construction materials

In a similar way to enhanced weathering, carbon emissions could be chemically absorbed through carbonation and stored for very long periods of time in construction materials.

There are several projects currently looking at ways to develop this technology, using different chemical ‘binders’. These include portland cement, non-hydraulic calcium silicate, industrial solid wastes, and materials based on magnesium.

They have the potential to store millions of tonnes of GHGs and, as an added benefit, the process could help make construction materials more environmentally friendly. The construction industry is currently responsible for 39% of global carbon emissions.

However, all these technologies are in the early stages of development. The challenges include finding the techniques that enable them to operate at scale, along with their cost.

Direct Air Capture and Storage (DACS)

DACS technology removes CO₂ directly from ambient air. This can then be stored for long periods, resulting in net reductions in emissions.

Huge fans are used to ‘suck’ in air, which then flows through a chemical that removes the carbon dioxide, or over special filters covered with the chemical.

When the chemical reacts with carbon in the air and is then heated, it forms a new compound. This can be pumped into deep geological formations and stored safely for long periods of time. Alternatively, the CO₂ absorbed can be re-used in industrial processes.

The major challenge for DACS schemes is that their fans use an enormous amount of energy, so they’re reliant upon a lot of electricity. This power may not always come from renewable sources and, even if it does, are they intermittent sources such as wind or solar?

Bioenergy with Carbon Capture and Storage (BECCS)

BECCS generates renewable energy from sustainable biomass and captures the CO₂ produced in the generation process. We’ve been trialling BECCS at our power station in North Yorkshire since 2019.

BECCS can give the UK the increasing amount of power it needs to drive the electrified economy when the wind’s not blowing and the sun isn’t shining. It can also be effectively carbon negative – removing more carbon than it emits.

The Climate Change Committee (CCC) – the independent body that advises the UK Government on climate change – says that negative emissions of this kind are essential. As a country, we won’t be able to meet our net zero commitments without them.

The Prime Minister has also reiterated the importance of CCUS. BECCS is a type of CCUS that can be put to work quickly and cost effectively. It’s based on proven technology, can be scaled up to remove gigatonnes of carbon emissions, and has the capacity to help the UK meet its net zero challenges.

What’s more, it costs less to deploy than other technology-based carbon capture and storage solutions – while at the same time helping to meet the growing need for electricity.

BECCS can also support the decarbonisation of hydrogen production, another source of energy that can help the UK reach net zero.

The Government’s announcement about ‘Viking’ being a CCUS cluster creates another possible pathway for us to realise our plans for BECCS – something we’re discussing with ministers. We hope to invest billions by 2030 to help these plans succeed.

Such investment and support is vital: the time for carbon capture and storage is now. The longer we leave it, the less time we’ll have to build and/or convert the facilities required to capture and store all the emissions the UK needs.

If you’d like to find out how BECCS and our other services can help your organisation, please contact us.