CENA-InfoHub

A

Advanced Biofuels

Advanced biofuels are produced from non-food-based raw materials such as agricultural residues, algae or wood waste. The biogenic waste and residual materials permitted in Europe are listed in the annex IX of EU Renewable Energy Directive RED II.

AKKL

The Climate-neutral aviation working Group (AKKL) was set up in autumn 2022 under the joint leadership of the Federal Ministry for Digital and Transport and the Federal Ministry for Economic Affairs and Climate Action to discuss the achievement of the Federal Government's goals towards climate-neutral aviation with a broad group of stakeholders from industry, trade unions, environmental associations, research institutes, think tanks and representatives of the federal states.

Alternative fuels

Non-fossil fuels that contribute to the reduction of emissions in the transport sector, such as biogenic or synthetic fuels.

Aromatics

Aromatics are ring-shaped organic compounds characterized by delocalized electrons. They influence the knock resistance of fuel and improve the lubricity, density and material compatibility of aviation fuels.

ASTM

Alcohol-to-jet (AtJ) is a process for producing sustainable aviation fuels. In this process, biomass containing sugar and starch is fermented into alcohol, then dehydrated and subsequently processed into kerosene.

Aviation emissions

Greenhouse gases and pollutants emitted by aircraft, including carbon dioxide, carbon monoxide, nitrogen oxides, water vapor, soot particles and sulphate. Noise is also an aviation emission.

AZEA

The Alliance for Zero Emission Aviation (AZEA) is a voluntary European initiative of private and public stakeholders initiated by the European Commission to prepare for the commercial operation of hydrogen-powered and electric aircraft.

B

BImschG

Federal Immission Control Act (BImschG) regulates the legal framework for protection against harmful environmental impacts caused by air pollution, noise, vibrations and similar processes in Germany.

Biofuel

Fuel produced from renewable raw materials or waste, e.g. bioethanol, biodiesel and biokerosene.

Blending

The blending of sustainable aviation fuels with conventional kerosene.

Book & Claim

A trading model for sustainable fuels in which buyers purchase certificates that promote the use of sustainable fuels elsewhere without using the physical fuel at their own location.

C

C14-Method

Radiocarbon method for determining the proportion of biogenic carbons in fuels.

Cap & Trade-system

A market-based system designed to reduce emissions by setting upper limits (caps) and the trading of certificates (trade).

CBAM

The Carbon Border Adjustment Mechanism (CBAM) is the EU's CO₂ border adjustment system for certain imports, such as cement.

Climate Club

An idea that goes back to Nobel Prize winner William D. Nordhaus and envisions a multinational trade agreement to promote ambitious climate protection measures.

Climate compensation system

Mechanism for offsetting CO₂ emissions through investments in climate protection projects.

Climate impact

The influence of emissions and other factors on the climate, including CO₂ and non-CO₂ effects.

Climate neutrality

State in which all climate-damaging anthropogenic emissions are offset or avoided.

CO₂

Carbon dioxide (CO₂) is a greenhouse gas that is produced, for example, when fossil fuels are burned and contributes to global warming.

CO₂-neutral

A process is CO₂-neutral if it causes no net CO₂ emissions.

CO₂-neutrality

State in which no additional CO₂ emissions are released. This can be achieved both by reducing emissions and by offsetting them. In contrast to greenhouse gas neutrality, the term only refers to CO₂.

Compensation

Measures to offset the CO₂ emissions caused by investing in climate protection projects, renewable energies or CO₂ capture and storage.

Contrail cirrus

Long-lasting ice crystal clouds that form from condensation trails in particularly cold and moist layers of air.

Contrails

Linear clouds of ice crystals that form when kerosene is burned in aircraft turbines in cold ambient air.

CORSIA

The Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA) is a market-based climate compensation system of the International Civil Aviation Organization (ICAO).

D

DAC

Direct Air Capture (DAC) is a technology for capturing CO₂ from the atmosphere.

Decarbonization

Shift away from energy and material use of carbon-containing resources. Complete decarbonization is not possible in all areas.

Defossilization

Shift away from the use of fossil resources. However, carbon-based technologies are still being used. One example from the aviation sector is the use of synthetic fuels produced from CO₂ and H₂.

Drop-in fuel

A fuel that can be used in existing infrastructures and engines without adaptation, e.g. synthetic kerosene.

E

E-kerosene

Synthetic kerosene produced using renewable electricity, hydrogen and CO₂. Synthetic kerosene is a sustainable alternative to fossil kerosene.

Electrolysis

Electrolysis is a process in which electric power is used to split a chemical compound, e.g. to produce hydrogen.

Electrolyzer

An electrolyzer is a technical system for carrying out electrolysis. It is also used to produce green hydrogen by breaking down water into its components using renewable electricity.

Emission certificate

Permission to emit one tonne of CO₂ within the framework of emissions trading systems, such as the European Emissions Trading System (EU ETS).

Energy carrier

Energy carriers contain or store energy. Examples are hydrogen, batteries or fossil fuels.

EU-ETS

European emissions trading system with the aim of reducing greenhouse gas emissions in the EU.

F

Fischer-Tropsch synthesis

Chemical process to produce hydrocarbons from synthesis gas (mixture of carbon monoxide and hydrogen). The process plays a major role in the search for alternatives to crude oil for the production of liquid hydrocarbons.

Flight route optimization

Adaptation of the flight route, e.g. to reduce emissions and climate-impacting effects.

G

Greenhouse gases

Gases in the atmosphere that prevent heat from being re-radiated from the earth's surface into space and thus contribute to global warming. In addition to CO₂, greenhouse gases include methane, nitrous oxide, ozone and water vapor.

H

HEFA

Hydroprocessed Esters and Fatty Acids (HEFA) is a process in which used fats and oils are converted into sustainable aviation fuel.

Hybrid power

Drive system that combines several energy sources, e.g. electric motors and combustion engines.

Hydrogen propulsion

Possible drive systems in which hydrogen could be used as an energy source, either by direct combustion in turbines or by hydrogen fuel cells.

I

IATA

The International Air Transport Association (IATA) is an international umbrella organization for airlines.

ICAO

The International Civil Aviation Organization (ICAO) is the international aviation organization that sets uniform environmental standards for international air traffic.

Intermodality

Combination of different means of transportation for efficient transport routes.

J

Jet A-1 kerosene

Standardized jet fuel used in civil aviation worldwide.

K

Kerosene

Aviation fuel produced from fossil crude oil.

Kerosene substitutes

Sustainable alternatives to fossil kerosene, such as synthetic aviation fuels or biofuels.

Kopernikus

A funding program of the Federal Ministry of Education and Research for the development of innovative solutions for the energy transition, including Power-to-X technologies.

L

LCA

Method for assessing the environmental impact of a product or service over its entire life cycle.

M

Market ramp-up

The process by which new technologies are gradually integrated into the market and scaled up.

Micro-refineries

Small, flexible refineries to produce fuels.

Mitigation strategies

Measures to reduce emissions, for example.

Monitoring systems

Monitoring emissions and compliance with environmental standards in aviation.

MtJ

Methanol-to-jet (MtJ) is a chemical process to produce aviation fuel from methanol. In this process, olefins are synthesized from methanol, then oligomerized and hydrogenated.

N

Non-CO₂ effects

Climate effects caused by emissions other than CO₂, such as contrails, water vapor, nitrogen oxides and aerosols.

Non-drop-in fuel

Fuel that cannot be used without modifications to existing infrastructure and engines.

P

PtL

Power-to-Liquid (PtL) is a process in which synthetic fuels are produced using renewable electricity, hydrogen and CO₂.

PtL-Roadmap

Strategy of the German government to significantly develop and expand the production of power-to-liquid kerosene generated from renewable electricity in Germany.

R

RCF

According to the definition in the EU Renewable Energy Directive RED II, recycled carbon fuels (RCF) are liquid and gaseous fuels derived from liquid or solid waste streams of non-renewable origin. Also included are process and waste gas streams of non-renewable origin that arise as unavoidable and unintentional by-products in industrial processes.

REACH

EU regulation on the registration and authorization of chemicals.

RED

The Renewable Energy Directive (RED) is an EU directive for the support of renewable energies at European level. It sets binding targets for the share of renewable energy for the various sectors in the member states. It also regulates the sustainability criteria for renewable fuels and the required greenhouse gas savings for biofuels.

reFuels

ReFuels are renewable fuels and include advanced biofuels, electric fuels and hydrogen.

Registration process

Procedures for the certification and approval of new fuels or technologies.

Renewable aviation fuels

Fuels that come from renewable sources and can be CO₂-neutral.

Renewable energies

Energy sources that are renewable and low-emission such as solar or wind energy.

RLCF

The Renewable and Low-Carbon Fuels Value Chain Industrial Alliance (RLCF) is an industrial alliance of the EU Commission to promote the production and supply of renewable and low-carbon fuels in the aviation and shipping sectors.

RNFBO

Renewable Fuels of Non-Biological Origin (RFNBO) are renewable fuels that are not derived from biomass. These primarily include electricity-based fuels (Power-to-X), which are produced from renewable electricity, hydrogen and carbon dioxide through electrolysis and subsequent synthesis processes.

S

SAF-Allowances

Free emissions certificates for airlines for blending sustainable aviation fuels as part of the European Emissions Trading System (EU ETS).

SPK

Synthetic paraffinic kerosene (SPK) is a type of synthetic kerosene that is used as a sustainable alternative to fossil aviation fuel. SPK can be produced from various carbon sources.

Synthetic fuels

Synthetic fuels are produced by chemical synthesis from synthesis gas (usually hydrogen and carbon monoxide or carbon dioxide). Depending on the origin of the synthesis gas, a distinction is made between electricity-based (PtL, PtG), biogenic (BtL) or fossil (GtL, CtL) fuels, which are obtained using processes such as Fischer-Tropsch or methanol synthesis.

U

Ultrafine particles

Very small particles (<0.1 nanometers), most of which are produced by combustion and affect health and the climate.