Glossary

Blast furnace route

The blast furnace route is a method for producing unrefined iron from iron ore and coke that involves high carbon emissions.

Calcination

Calcination describes the process by which calcium carbonate (CaCO₃) is broken down into (CaO) and carbon dioxide (CO₂) – with the CO₂ being released as an emission.

Calcium cycle

The calcium cycle comprises the reversible reaction of limestone (CaCO₃) with carbon dioxide (CO₂). During carbonation, limestone binds CO₂ to form calcium carbonate. During the subsequent calcination, the carbon dioxide is released to regenerate the original limestone, thereby resulting in the creation of a cyclic process. These methods are utilised within carbon capture and usage technologies.

Calcium looping

Calcium looping is a technology for the separation and usage of carbon dioxide (CO₂) from industrial processes. In this process, calcium oxide (burnt lime) and calcium carbonate (limestone) are used to separate and release CO₂ repeatedly during cyclic reactions.

Carbonation

During carbonation, CO₂ reacts with certain substances to form carbonates. As one example, burnt lime is transformed into limestone by the addition of CO₂. This method has the potential to be used in the production of synthetic limestone or for carbon capture and storage, both of which can contributes to reductions in greenhouse gas emissions.

Carbon border adjustment mechanism (CBAM)

The carbon border adjustment mechanism is a trade instrument to protect against carbon leakage that has been proposed by the EU Commission. This envisages levying fees on certain imported products (e.g. steel, aluminium and fertilisers) as appropriate to their carbon footprint when these products are sourced from regions without a carbon price or with a price lower than the EU emissions trading price.

Carbon capture and storage (CCS)

Carbon capture and storage (CCS) refers to technologies for capturing and storing carbon dioxide (CO2), so as to prevent its release into the atmosphere by storing it underground instead.

Carbon capture and utilisation (CCU)

Carbon capture and utilisation (CCU) refers to the capture of carbon dioxide (CO2) followed by its subsequent use as a raw material in chemical processes.

Carbon contract for difference (CCfD)

Carbon contracts for difference are a contract-based funding instrument utilised in particular for the operation of low- and zero-carbon manufacturing facilities. This instrument involves the financial compensation of parties to the contract in terms of the cost difference between actual CO₂ avoidance costs and the current carbon price.

Carbon leakage effects

The term refers to situations where companies outsource production – and the associated greenhouse gas emissions – to locations outside the EU with less onerous regulations in relation to climate change.

Carbon leakage protection

Measures introduced to avoid carbon leakage effects.

Carbon source

Carbon sources in manufacturing include emissions from the combustion of fossil fuels such as oil, gas and coal.

Carbon sink (natural)

Carbon sinks such as forests and oceans absorb and store atmospheric carbon.

Chemical recycling

Chemical recycling refers to the conversion of plastics into their basic chemical constituents for subsequent processing into new chemical products.

Chlorine-alkali electrolysis

An umbrella term for a group of electrochemical methods for the production of the basic chemical chlorine from sodium chloride. Hydrogen and sodium hydroxide are produced as by-products.

Climate neutrality

Climate neutrality describes a situation where all human activities – including but not restricted to greenhouse gas emissions – have no net impact on the climate as a system. Climate neutrality is often used as a synonym for carbon neutrality.

CO₂

CO₂ is the molecular formula for carbon dioxide, the greenhouse gas largely responsible for driving climate change.

CO₂ equivalent (CO₂e)

A unit of measure that describes the greenhouse gas potential of various chemical compounds relative to CO₂. Converting figures to their CO₂ equivalents (CO_2e) makes it possible to compare various emissions more effectively in terms of their climate impact.

Decarbonisation

Decarbonisation is an important step on the path towards greenhouse gas neutrality. The term is an umbrella term for carbon exit strategies. In manufacturing, this refers to a changeover to zero-carbon or carbon-neutral production processes.

Defossilisation

Defossilisation refers to the process of transitioning from fossil sources of carbon (such as coal and natural gas) to renewable sources of carbon (such as direct air capture, biomass or materials managed in a loop), whether for use in energy production or as raw materials.

Direct air capture (DAC)

DAC refers to filters and other separation methods for harvesting CO₂ directly from ambient air.

Disruptive innovation

Disruptive innovations are technologies that are fundamentally different to established methods and processes, and supplant or replace them wholesale.

Electrolysis

Electrolysis is a process that uses electrical energy to break down chemical compounds into their constituent parts.

Energy-intensive industries

The energy-intensive basic materials sector includes steel production, basic chemicals, cement production, aluminium production, glass production and paper manufacturing in particular, as well as other sector industries.

Fischer-Tropsch process

This is a method for the production of hydrocarbons from a mixture of carbon monoxide (CO) and hydrogen (H₂), which is known as ‘synthesis gas’.

Fly ash

Particulates produced from the combustion of a fuel. Also known as flue ash or coal combustion residuals (CCR).

Green electricity

Green electricity is a term used to describe electrical energy produced by renewable energy sources.

Greenhouse gas neutrality

Greenhouse gas neutrality means that no greenhouse gas emissions are caused by a specific process. Often, greenhouse gas neutrality is used as a synonym for climate neutrality.

Green hydrogen

Green hydrogen is produced by the electrolysis of water, with the electricity required for the electrolysis being sourced solely from renewable power.

Haber-Bosch process

The Haber-Bosch process is a method for the production of ammonia from nitrogen and hydrogen.

Hydrocarbons

Hydrocarbons are chemical compounds made only from carbon and hydrogen. Fossil fuels are also hydrocarbons.

Limestone cycle

The limestone cycle comprises the reversible reactions of limestone (CaCO₃) with carbon dioxide (CO₂).

• Step 1 – calcination (CaCO₃ → CaO + CO₂):  on heating, calcium carbonate (CaCO₃) thermally decomposes (is degraded by heat during an endothermic process) to produce calcium oxide (CaO) and carbon dioxide (CO₂).
• Step 2 – hydration (CaO + H2O → Ca(OH)2): calcium oxide reacts with water (H₂O) to form calcium hydroxide (Ca(OH)₂), also known as hydrated lime.
• Step 3 – carbonation (Ca(OH)₂ + CO₂ → CaCo₃ + H₂O): this is the reaction that takes place when carbon dioxide is passed through hydrated lime to form calcium carbonate.

Methane pyrolysis

Methane pyrolysis refers to the thermal decomposition of methane into hydrogen and solid carbon. If renewable energy is used for the generation of process heat, then the end product is referred to as ‘turquoise’ hydrogen.

Sector coupling

Sector coupling describes the use of green electricity to supply heat (Power-to-Heat), power transport (Power-to-Gas, Power-to-Liquids) or provide raw materials for use in primary industries (Power-to-Chemicals).

Steamcracker

Steamcrackers are facilities used for the production of organic basic chemicals (e.g. ethylene) by the steam cracking of long-chain hydrocarbons sourced from fossil raw materials.

Water electrolysis

Water electrolysis describes the decomposition of water into oxygen and hydrogen by the application of electrical power. If electricity from renewable sources is used, the end product is also referred to as ‘green’ hydrogen.