6 carbon removal pathways that can help you reach Net Zero

What is carbon removal?

Carbon removal is the process of removing and storing carbon emissions from the atmosphere. There are different carbon removal pathways, each with a different approach to removing and storing carbon. Some pathways rely on nature (nature-based solutions) and can store carbon for decades (short-lived storage). Others rely on technology (technology-based solutions) and can store carbon for thousands of years (long-lived storage). All pathways have the potential to help the UK reach net zero.

Nature-based solutions

There are several nature-based pathways to removing and storing CO₂ and other Greenhouse Gases (GHGs). Nature-based solutions provide ‘short-lived’ storage because the carbon is only stored for decades.

Afforestation and Reforestation

Afforestation and reforestation 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.

There’s also a risk of carbon being re-released into the atmosphere due to forest fires.

Blue carbon

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

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 solutions

There are several technology-based pathways that remove and permanently store CO₂ including enhanced weathering, biochar, direct air capture and storage (DACS) and bioenergy with carbon capture and storage (BECCS). Because they use a combination of technology and nature, biochar and BECCS can also be considered hybrid solutions.

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.

Direct Air Capture and Storage (DACS)

DACS technology removes CO₂ directly from ambient air. This is then injected underground for permanent storage, resulting in net removals.

Huge fans are used to ‘suck’ in air, which then flows through filters that capture the carbon dioxide from the air.

When the chemical is then heated, it releases the CO₂ which is then pumped directly into deep geological formations and stored permanently.

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, therefore potentially leading to increased emissions from power generation.

Hybrid solutions

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.

Bioenergy with Carbon Capture and Storage (BECCS)

BECCS generates renewable energy from sustainable biomass and captures the CO₂ produced in the generation process, storing the CO₂ underground for thousands of years. 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.

BECCS is a type of carbon dioxide removal (CDR) 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 Carbon Capture Use and Storage (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.