Suck carbon dioxide directly from the air

The new British nuclear power plant Sizewell C is to receive a CO2 extraction system. But the high cost of the technology is problematic.

Model of the planned large nuclear power plant Sizewell C on the east coast of England

Dhe planned large-scale nuclear power plant Sizewell C on the east coast of England is to be supplemented by a technical innovation. The British government is giving funding to develop a system that will filter carbon dioxide (CO2) directly from the air, thereby helping to combat climate change. The so-called “Direct Air Capture” technology (DAC) is already being tested in some pilot plants in other countries. At a quarter of a million pounds, the public funding now approved is not particularly high, but an important signal that the London government believes the technology is promising.

“We are strengthening our arsenal against climate change and supporting innovations and companies that create green jobs in the UK,” said Anne-Marie Trevelyan, Secretary of State for Energy. In total, the Johnson administration has pledged a billion pounds (1.15 billion euros) to build several large carbon storage clusters in the country. With the planned large-scale DAC system in Sizewell, once it is running, up to 1.5 million tons of CO2 will be sucked out of the air and neutralized every year.

This would correspond to two thirds of the emissions from the British railways, whose electric and diesel passenger trains emitted around 2.4 megatons of CO2 a year before the Corona breakdown. The DAC project in Sizewell is being developed by a consortium. This includes experts from the University of Nottingham, the engineering and construction companies Atkins and Strata Technology, and the energy technology company Doosan Babcock.

Energy intensive process

The Sizewell C nuclear reactor under construction, which is mainly being built by the French state-owned company EDF, is not without controversy because of its high costs of more than 20 billion pounds. After nine years of construction, Sizewell C is expected to generate 3.2 gigawatts of power and thus take over 7 percent of the national electricity generation, enough for 6 million households. The DAC system should then bring an extra climate plus. “Operating direct air capture with heat from Sizewell C can make the power plant CO2 negative,” explains Sizewell Finance Director Julia Pyke. It is important, she adds, to find a way to reduce the cost of the technology.

So far, DAC technology is still in its infancy. According to a report by the International Energy Agency (IEA) from mid-2020, only 15 plants are running in Europe, the United States and Canada. According to the IEA, they remove around 9,000 tons of CO2 from the air each year. The gaseous carbon dioxide is filtered from the ambient air using a chemical process and either stored underground, chemically bonded in the long term or converted into synthetic fuels.

However, the process is energy-intensive and the costs have so far been very high. According to estimates in the literature, the IEA cites a range of theoretically 100 to 1000 dollars per ton of CO2. The World Resources Institute predicts that real costs could drop to $ 150 to $ 200 in the next five to ten years. But that is still significantly more expensive than reforestation with far less than 50 dollars per ton of CO2. Nevertheless, scientists and companies see potential in DAC technology.

In Switzerland, the start-up Climeworks installed the first commercial system in Hinwil, Canton Zurich, on the roof of a waste incineration plant four years ago. It absorbs almost 1000 tons of CO2 a year. Among other things, it is sold to a nearby nursery that uses it as a fertilizer for plants. Last year, Climeworks raised $ 110 million from investors, and the company is now building a geothermal power plant with a DAC system in Iceland that will suck out 4,000 tons of CO2 a year and store it in the ground.

The plans of Carbon Engineering from Canada, in which Bill Gates is also involved, are many times larger. Together with the Texan oil company Occidental, it has started building DAC systems in the southern United States, which are supposed to filter up to a million tons of CO2 from the air annually – about as much as 40,000 trees do while growing. Carbon Engineering speaks of a price of 100 dollars per ton of CO2. That could be interesting if the price for emissions certificates continues to rise.