Climate neutrality not without negative emissions

Climate neutrality cannot be achieved by expanding the use of renewable energy sources alone. They must be complemented by technologies. They should capture CO2 from exhaust gases or the atmosphere, store it and, in the best case, even utilise it.

More and more governments and organisations have committed to the goal of climate neutrality. They are seeking to significantly expand the use of renewable energy sources and improve energy efficiency. But that alone will not be enough. Because, it will not be possible to achieve the goals of the Paris Climate Agreement in time without negative emission technologies.

According to the International Energy Agency (IEA), at least 15 per cent of the necessary emission reductions will have to be realised through carbon capture, utilisation and storage (CCUS) technologies. That means an almost 100-fold increase in CCUS capacity by 2050. Dr Carsten Rolle, secretary general of the German Member Committee of the World Energy Council, is also convinced. “The Paris climate goals will not be achievable without integrating negative emissions into climate protection strategies. It is all the more urgent for policy-makers and society at large to discuss and promote further development and application.”

Balancing out unavoidable emissions

Climate neutrality, as enshrined in the Paris Climate Agreement, means achieving a balance between the emission of man-made greenhouse gas emissions on the one hand and the removal of gases by sinks on the other. It is for those sinks that negative emission technologies are needed. Because, despite all the progress made in expanding renewable energy sources and reducing energy consumption, there will still be greenhouse-gas emissions in the future. And they can only be avoided – if at all – at very high cost. This creates the need for negative emissions to be removed from the atmosphere. Added to this is the need to compensate for emissions caused by time lags in climate protection efforts. “The later the goal of completely avoiding all anthropogenic emissions is achieved, the greater the need for negative emission technologies and sinks will be later on,” asserts Carsten Rolle.

Long-term underground storage

Carbon capture has been used for decades to improve the quality of natural gas. Thanks to new technologies, however, CO2 can now also be stored for long periods of time. Like in Iceland, for example. There, Swiss company Climeworks is building the world’s largest Direct Air Carbon Capture and Storage (DACCS) facility for the fossilisation of atmospheric CO2. It extracts carbon dioxide from the ambient air and releases CO2-free air back into the atmosphere. The CO2 filtered from the air is transported below the Earth’s surface. Where it reacts with the basalt rock through natural processes. And over a period of several years mineralises to form carbonates. This permanently removes the carbon dioxide from the atmosphere. The facility will run 24/7, filtering 4,000 tonnes of carbon dioxide from the atmosphere a year.

Carbon capture and storage offers a potential solution for the raw material industries in particular. And most especially for the cement industry, which currently has no prospect of attaining carbon neutrality. As one example, starting in 2024 a facility at Heidelberg Cement’s Brevik cement works in Norway will capture 400,000 tonnes of CO2 annually. Which will then be permanently stored. The aim is to reduce the CO2 emissions of the cement produced at the plant by 50 per cent.

From climate gas to raw material

The permanent storage of carbon dioxide is only one possibility, however. A still more exciting prospect is to imbue the CO2 “waste product” with value, transforming it into marketable industrial and commercial products. CO2 is a versatile molecule that can be chemically converted into a wide range of products. Including motor fuels, chemicals, building materials and polymers. The Covestro corporation, for example, has developed a technology by which CO2 can be used as a raw material for sustainable plastics. “The plastics industry can contribute to combating climate change by switching to greenhouse gas-neutral production. To achieve that, we need to move away from oil and use alternative raw materials such as CO2,” says Covestro CEO Dr Markus Steilemann.

The process uses chemical catalysts to drive reactions between CO2 and a conventional feedstock. This produces polymers in a more sustainable and economically viable way. Although the process can only replace the crude oil in part, it does produce plastics whose constituents can be more easily recycled. The CO2-based material is already used to make soft foam for mattresses, padding in shoes, and in car interiors. Elastic textile fibres are on the verge of attaining market maturity. Research projects have shown that CO2 can also be used for insulating materials made of rigid foam. Additionally for surfactants, such as in detergents.

In this way, harmful climate gas has been turned into a valuable raw material. And a further, sustainable step has been taken towards climate neutrality.


Related Posts