Options for CO₂ transport
The example of German cement production, where a single plant generates an average of 1.5 million tonnes of CO₂ emissions per year, clearly shows how central the transport of CO₂ emissions is in the context of utilisation or storage (CCU or CCS).
Various options are currently available, which differ primarily in terms of capacity and cost-effectiveness. To illustrate this, the average annual emissions of a single cement plant of 1.5 tonnes of CO₂ are used as the basis for the calculation.
- Truck transport offers a high degree of flexibility, but is not very efficient due to its limited capacity (approx. 20 tonnes of CO₂ per truck) and high emissions. To transport 1.5 million tonnes of CO₂, around 75,000 truck journeys would be necessary each year.
- Transport by rail can move larger quantities (approx. 2100 tonnes of CO₂ per train) more efficiently. For 1.5 million tonnes of CO₂, 712 train journeys per year would be required.
- Inland vessels offer even higher capacities (approx. 4,200 tonnes of CO₂ per vessel). Transporting 1.5 million tonnes of CO₂ requires 357 ship journeys per year. This transport route is energy-efficient, but limited to locations close to the water.
- Pipelines are considered the most economical option for large-scale CO₂ transport: a pipeline (DN 300) with a transport capacity of 180 tonnes of CO₂ per hour (which corresponds to 1.5 tonnes per year) is the most efficient and environmentally friendly transport option in the long term.
Conclusion: While lorries and rail offer flexibility and transport by ship is associated with local restrictions, pipelines would be the most cost-effective option in the long term, especially for larger volumes.
Carbon capture and utilisation
Carbon capture and utilisation (CCU) describes the capture of CO₂ from industrial processes and its use as a raw material for the manufacture of products such as synthetic fuels, plastics or building materials. The process comprises three main steps:
- CO₂ capture from sources such as power plants, cement factories or steel production
- Transport of the captured CO₂
- Utilisation in chemical processes or underground storage
In Germany, key players such as BASF, Covestro and Thyssenkrupp as well as research institutions such as the Fraunhofer-Institut für Solare Energiesysteme (ISE) and the Bundesministerium für Wirtschaft und Klimaschutz (BMWK) are active. Sectors such as the chemical industry, energy industry and cement production play key roles.
Bundesumweltamt (UBA), the use of CO₂ in German industry is still just under 1 %, while in the EU the rate is around 0.1% of total CO₂ emissions.
The UBA and Bundesministerium für Wirtschaft und Klimaschutz (BMWK) play an important role in promoting and regulating CCU technologies. Sectors such as the chemical industry (e.g. BASF), energy suppliers (such as RWE) and companies in the field of sustainable building materials rely on CCU to improve their carbon footprint. Trade associations such as the Verband der Chemischen Industrie (VCI) support research and development to promote CCU as a key technology for the energy transition.
Carbon capture and storage
Another key technology for reducing CO₂ emissions is carbon capture and storage (CCS), in which carbon dioxide is captured from industrial processes, transported and stored in underground geological formations. The process consists of three steps: Capture (where CO₂ is filtered from exhaust gases), transport and storage in suitable geological formations such as depleted natural gas fields.
In Germany, the Kohlendioxid-Speicherungsgesetz (KSpG), which was passed in 2012, was intended to create the legal framework for CCS - initially for testing and research purposes within a narrow quantitative framework (max. 4 million tonnes per year). Legal experts criticise that the law has failed to achieve its actual purpose due to key weaknesses in the approval of CO₂ pipelines and has prevented CCS in Germany to date: According to the legal definition, „carbon dioxide pipelines“ are only those that transport CO₂ to a cavern (underground storage facility). In July of this year, a draft amendment to the KSpG was drawn up with the aim of „creating a legal framework for the permanent storage of carbon dioxide and the associated transport on an industrial scale“. This is intended to supplement the first key issues paper on the BMWK's Carbon-Management-Strategie.
The Carbon-Management-Strategie published by the Bundesministerium für Wirtschaft und Klimaschutz (BMWK) in 2023, the key points of which were approved by the Federal Cabinet in August, has brought CCS back into the focus of German climate policy. The German government recognises CCS as a complementary measure for reducing industrial emissions, particularly in sectors such as cement, chemicals and steel, which are difficult to decarbonise. Particular attention is being paid to the development and expansion of infrastructure as well as the promotion of research and pilot projects.
However, the political discourse remains divided: While industry associations see CCS as indispensable for achieving climate targets, environmental protection organisations continue to express concerns about long-term safety and the risk that CCS could be used as an excuse to use fossil fuels for longer. However, the German government emphasises that CCS should only be used in combination with the reduction of fossil fuels.
