It has been heralded as an innovative way to enable Britain to reduce its greenhouse gas emissions.
But what exactly is carbon capture, and how effective can it be?
Prime Minister Rishi Sunak is certainly a believer, having announced that two carbon capture and storage facilities it will be built as part of a £20bn investment to curb the UK’s carbon footprint.
But many opponents are skeptical of what they say is “fledgling science” that is still in its infancy and has not been scaled up to show exactly how much carbon can be stopped from entering Earth’s atmosphere.
Here MailOnline takes a closer look at how carbon capture and storage actually works and why it’s so controversial.
CCS is a technology designed to capture carbon emissions from power plants, industrial processes and other sources, and store them permanently underground.
WHAT IS CARBON CAPTURE AND STORAGE?
Carbon capture and storage (CCS) is a relatively new technology that could greatly reduce carbon emissions and, in turn, combat global warming.
The technology is designed to capture carbon dioxide (CO2) emissions and store them permanently underground, as a greener alternative to releasing them into the atmosphere.
According to the government, one CSS plant could potentially store a total of 78 billion tons of carbon, the same weight as 15 billion elephants.
Different options are being investigated to try to reduce total CO2 emissions, but CCS is the main way to reduce CO2 emissions from large industrial sources.
HOW DOES IT WORK?
When fossil fuels are burned, carbon dioxide is produced, a greenhouse gas that contributes to global warming.
CCS, therefore, involves capturing waste gases right at the source of their creation, such as power plants and industrial facilities that make steel and cement.
CCS facilities typically consist of a stack of metal ‘air scrubbers’, which absorb CO2 from the surrounding ambient air using fans before removing it via a chemical filter.
CCS facilities typically consist of a stack of metal ‘air scrubbers’, which absorb CO2 from the surrounding ambient air using fans before removing it via a chemical filter. Pictured is a carbon removal facility from Carbon Engineering, a Canada-based clean energy company
CCUS involves the capture of CO2, usually from large point sources such as power generation or industrial facilities that use fossil fuels (file photo)
UK carbon capture plants under development
– Acorn (Scotland)
– Viking (Humber)
– HyNet (Liverpool/North Wales)
– East Coast Group (Teesside and Humber)
Once extracted, the CO2 is transported to a storage site via pipelines or, often when the storage site is far away, by road vehicles or ships.
The storage site is usually an underground cavern, such as a depleted oil or gas reservoir, or a porous rock formation that has good gas storage potential, known as a saline aquifer.
The carbon dioxide is then left there permanently, but is monitored to ensure it remains safely contained and is not prone to leaks.
Another slightly different process known as ‘carbon capture, use and storage’ (CCUS) involves reusing CO2 in industrial processes by turning it into plastics, concrete or biofuels, for example.
WHY IS CCS CONTROVERSIAL?
CCS has been criticized for encouraging continued use of carbon-emitting fossil fuels rather than switching to renewable energy sources.
Mike Childs, policy director for the environmental organization Friends of the Earth, said the government is simply “championing for the dirtiest and most expensive fossil fuels.”
“Talking about carbon capture and storage is an obvious attempt to put a green shine on the prime minister’s announcement,” he said.
Prime Minister Rishi Sunak is pictured on Monday during a visit to the Shell St Fergus gasworks in Peterhead, Aberdeenshire. Scottish government bets on Acorn carbon capture and storage (CCS) project despite controversy and doubts about technology
“Even if it ever works, which is unlikely in the short term, CCS won’t capture all of the climate pollution caused by burning fossil fuels or address the significant emissions that are created when oil and gas are extracted.”
The technology also has safety concerns: After being stored underground, some experts fear the CO2 could leak out and contaminate nearby water supplies or create tremors caused by pressure buildup underground.
The long-term effects that carbon dioxide and the pipelines that carry it can have on the environment are also not fully understood.
Also, separating and storing carbon dioxide is an energy-intensive process in itself, so it could reduce the efficiency of power plants.
WHERE IS CCS ALREADY USED?
CCS has been in operation since 1972 in the US, where several natural gas plants in Texas have captured and stored more than 200 million tons of CO2 underground.
According to the CCS Global Institute Report 2022there were 194 large-scale CCS facilities around the world at the end of the year, 80 of which are in the US.
The UK is still awaiting its first CCS facility, although a plant that uses emitted CO2 rather than stores it (CCUS) opened in Cheshire last year.
In June last year, a CCUS facility opened in Northwich, Cheshire, which is said to remove up to 40,000 tonnes of CO2 each year.
Liquid carbon dioxide is stored in these units before being converted to baking soda.
At the facility, CO2 is captured from the pipelines of a methane gas power plant also located at the facility, before being purified, cooled, and liquefied.
It uses a proprietary process to convert purified CO2 into sodium bicarbonate, a compound used to make baking powder and pharmaceutical tablets.
WHERE WILL THE CCS PLANTS BE IN THE UK?
As part of the Prime Minister’s £20bn round of funding for green carbon capture schemes, recently confirmed CCS facilities will open in Scotland and the Humber.
Sunak has given the green light to the ‘Acorn’ project in north-east Scotland ahead of a visit to Aberdeenshire, alongside the Viking project in Yorkshire.
They are the third and fourth CCS installations to be confirmed, following previous support from HyNet in the North Wales region and the East Coast cluster in the Humber and Teesside regions.
Locations of CCS projects currently under development in the UK
The government expects HyNet and East Coast Cluster to roll out in the mid-2020s, while Acorn and Viking will follow by 2030.
The plants are located close to the coast so that the captured CO2 is transported for storage under the nearby sea.
The Government has also announced that around 100 new oil and gas licenses will be granted in the North Sea, to boost domestic oil and gas production.
Essentially, these give companies permission to extract oil and gas from new offshore locations, drawing criticism from some experts.
Stuart Haszeldine, professor of carbon capture and storage at the University of Edinburgh, called it “a deal with the devil.”
“It is essential to ensure that this carbon storage with the Acorn or Viking projects provides a real decrease in emissions,” he said.
‘The storage of 2 or 5 million tons of CO2 per year must not become a political excuse to release an additional 10 or 100 million tons of CO2 from the development of new oil and gas extractions through many dozens of new licences’ .
Fossil fuels versus renewable energy sources
Solar – light and heat from the sun.
Wind – through wind turbines to convert electrical generators
hydro – captured from fast running or falling water
Tidal – energy from the rise and fall of sea level
geothermal – energy generated and stored on Earth
biomass – organic material burned to release stored energy from the sun
Although nuclear power is considered clean energy, its inclusion in the renewable energy list is a topic of great debate.
Nuclear power itself is a renewable energy source. But the material used in nuclear power plants, uranium, is not renewable.
Renewables contrast with the most damaging fossil fuels – oil, coal and gas.
They are considered fossil fuels because they formed from the buried, fossilized remains of plants and animals that lived millions of years ago.
Due to their origin, fossil fuels are high in carbon, but when burned they release large amounts of carbon dioxide, a greenhouse gas, into the air.
Source: EDF Energy /Stanford University