Glossary

On this page we explain some key terms that may be important for understanding CO₂ utilisation technologies. Do you know any other terms that might be difficult for laypersons to understand? Get in touch with us.  

Carbon capture technologies

There is currently one class of technology which is currently the benchmark for a large-scale capture of CO₂: wet-chemical washing processes with the aid of strong alkaline solutions, in particular, so-called “amine scrubbing”. Wet-chemical processes involve diverting an exhaust stream through a so-called absorber solution. The CO₂ contained in the exhaust stream is then absorbed by the molecules of the absorber solution and separated from the remaining exhaust stream. In the case of amine scrubbing, this absorbing mixture is based on a solution of amines.

Capture

Within the scope of CCU technologies capture is understood as the process by which CO₂ is filtered out of industrial waste gases. The goal here is that, following the capture process, the CO₂ is available in sufficiently high purity in order to allow it to be used or geologically compressed.

Catalysis/Catalyst

The term catalysis defines the act of influencing a chemical reaction with the aid of a catalyst, with the goal of initiating a reaction, accelerating a reaction or reducing the necessary energy for a reaction, as well as causing specific reaction processes. For CCU processes, breakthroughs in catalysis research were essential. They made first processes feasible and/or energetically sensible, thus enabling further processing on the inert material CO₂.

Circular economy/(Closed loop) recycling management/German Life-Cycle Resource Management Act (Kreislaufwirtschaftsgesetz)/Recycling (Closed loop)

Recycling management defines a concept of leading resources that are completely utilised in production into further utilisation. Recycling processes are part of this concept, but are also supplemented by other forms of further use, such as cascade utilisation. In this study, both terms are used: (closed loop) recycling management stands for the conception of the objectives while recycling is a concrete process on the way to this. The European Guidelines for dealing with waste were determined by law in the German Life-Cycle Resource Management Act (KrWG) in 2012.

CCS – geologican storage of CO₂

Carbon Capture and Storage (CCS) defines the capture and subsequent geological storage of carbon dioxide from industrial waste gases, with the goal of removing CO₂ durably from the atmosphere. Storage is regarded as feasible, for example, in underground salt water layers and former crude oil and natural gas sites.

Delay of emissions

After a particular period of time, the used CO₂ will be emitted again. Depending on the lifetime of the respective CCU product, the CO₂ can be stored for days or weeks (e.g. synthetic fuels), years (e.g. polymers) or decades or centuries (e.g. cement).

Direct or physical utilisation

The usage of carbon dioxide in industrial processes without chemical transformation is defined as direct utilisation or physical of CO₂. This type of utilisation can take place in solid or liquid form and is already commonplace in diverse production processes, for example, carbonic acid in drinks, dry ice for cooling of foods, in fire extinguishers or as fertiliser in greenhouses.

Emission saving/reduction potential

It must be considered that the evaluation for usable CO₂ emissions are not to be considered equal with actual saved CO₂ emissions, since all conversion technologies also require energy. For each individual CO₂ utilisation technology, it is therefore necessary to determine the potential for CO₂ savings individually – this can be higher or lower than the amount of CO₂ which can be used. It is even possible that an increase in emissions will occur.

End of life

The term “end of life” denominates the final phase in the life cycle of a product. This includes processes like the incineration of a product, its disposal on a landfill or its entering in a recycling process.

Life Cycle Assessment/ecological balance/life cycle analysis

A Life Cycle Assessment or LCA is a systematic analysis of the possible effects on the environment of a production process of an interim or end product. Ideally, this analysis should include the complete lifetime of a product (“cradle to grave”) or up to the point in time of the finished manufacture of an (interim) product (“cradle to gate”). For CCU products, this means, in particular, the inclusion of all of the processes upstream and downstream from the actual CCU core process, in order to make a holistic assessment of the possible effects on the environment possible

Material utilisation of CO₂

CO₂, if chemically transformed, can serve as a raw material for the production of carbon compounds of energetically higher or of lower value. This so-called material utilisation of CO₂ as a component of materials, chemicals and minerals has been common for some time in special pharmaceutical products (e.g. headache tablets), solvents or, on the larger scale, fertilisers (urea). Furthermore, the material utilisation of CO₂ is already currently technically feasible in the manufacture of plastics and foams, paints and coatings, and building materials similar to cement (so-called minerals). These new procedures usually involve innovative processes to replace conventional production processes, but which are currently still in very early stages of development or have only recently become feasible due to breakthroughs in catalysis research, and which will now, first of all, have to be demonstrated on an industrial scale.

Minerals/Mineralisation

Mineralisation is a process of material utilisation of CO₂, with the aid of which, for example, industrial waste such as ash and sand can be processed with CO₂ from waste gases to so-called minerals. Such minerals can be, for example, cement-like or other building materials similar to concrete for road works or other similar purposes.

Permanent storage/binding of CO₂

Permanent storage or binding means a duration of more than 1.000 years.

Power-to-X – PtX/PtG/PtL

Power-to-X defines, as a generic term, all the processes which transform energy from renewable sources, for example, in the form of hydrogen or electricity, together with CO₂, to diverse energy sources (for example Power to gas – PtG, or Power to liquids – PtL). This technology plays an important role in the energy transition policies as an option for flexible deployment and storage at peaks within the scope of the production of renewable energies, but is also open to other possibilities for large-scale application of CCU technology. Due to the low prices of fossil energy, these new technologies are, however, currently not competitive options to conventional fuels.

Synthetic fuels/ energy carriers

Generally, it is also feasible to use carbon dioxide as a raw material in order to manufacture energy carriers. It is possible, for example, to produce the following energy carriers from CO₂ by means of diverse processes:

• liquid fuels such as methanol, diesel
• gaseous fuels such as methane/synthetic gas.

Such energy carriers can directly serve the mobility sector or could find future use as energy storage, in order to use peaks in the generation of renewable energies.