What is carbon capture, usage and storage – and can it trap emissions?

Technology that can keep carbon dioxide emissions from entering the atmosphere and stoking global heating will be essential to tackle the growing climate crisis, experts say. But how does it work, and why will it make a difference in fighting climate breakdown?

What is carbon capture, usage and storage (CCUS)?

This refers to a chain of different technologies that can keep the carbon dioxide produced by major factories and power plants from reaching the atmosphere and contributing to global heating. The first step is to fit factory chimneys with solvent filters, which trap carbon emissions before they escape. The gas can then be piped to locations where it can be used or stored. Most carbon dioxide will be injected deep underground – where fossil fuel gas comes from in the first place – to be stored where it cannot contribute to the climate crisis. But some could be used to help make plastics, grow greenhouse plants, or even carbonate fizzy drinks.

Where is carbon capture technology being used?

There are about 20 CCUS projects operating commercially, nowhere near enough to clean up the world’s carbon emissions. The early forerunners are in the US, Canada, Norway and China. Although CCUS has had a slow start, 30 new projects have been agreed in the past three years, the International Energy Agency says. The watchdog says there must be many more to keep carbon emissions from heating the world to more than 1.5C above pre-industrialised levels. In the UK, early-stage projects are being developed near the Humber estuary and in Aberdeen, the capital of the North Sea oil and gas industry.

Why do we need carbon capture?

According to the IEA, CCUS projects could reduce global carbon dioxide emissions by almost a fifth and reduce the cost of tackling the climate crisis by 70%. One of the key reasons CCUS is necessary is because heavy industry – fertiliser producers, steel mills and cement makers – would be difficult and expensive to adapt to run on cleaner energy. Another key reason for developing CCUS is to unlock the potential of hydrogen.

Hydrogen is a clean-burning gas that could be used to replace fossil fuels in planes, trains, trucks, factories and even in home heating. But without carbon capture being used to produce hydrogen from fossil fuel gas, carbon emissions would be released into the atmosphere. Hydrogen could still be made by splitting water molecules into hydrogen and oxygen gases using a renewable energy powered electrolyser machine, but this would be far more expensive.

How are the UK’s carbon capture ambitions going?

They stumbled in 2015 after the government abandoned a £1bn scheme to set up a carbon capture project alongside coal-fired power plants because of cost concerns. Three years later, ministers returned to the table with less money and a new idea: to use CCUS for heavy industry instead.

Large energy companies, including National Grid, Drax and the Norwegian oil company Equinor, have since begun work on a full-scale CCUS project in the Humber area, and a handful of UK universities have pursued a separate project in Aberdeen.

National Grid has said the carbon emissions from UK’s electricity system could turn negative by as early as 2033 if it used carbon capture technology alongside more renewable energy to reach its climate goals.