synthesis gas (syngas) is a gas mixture that consists mainly of hydrogen (H₂) and carbon monoxide (CO) in variable proportions. Depending on the raw materials used and the production processes, it may also contain small amounts of carbon dioxide (CO₂), methane (CH₄) and traces of other gases.

Syngas is mainly used to produce hydrocarbon fuels such as diesel fuel and methanol, as well as to produce industrial chemicals, particularly ammonia. Syngas can also be produced from biomass or agricultural waste materials and is therefore considered a form of renewable energy, thereby contributing to a sustainable raw materials and energy economy.

As a result of the increasing expansion of biomass gasification plants in recent years, a large proportion of the synthesis gas produced each year is already obtained from renewable raw materials. The focus here is primarily on the steam reforming of methane. At high temperatures of 700–900 °C and pressures in the range of 200 to 300 bar, the addition of steam or oxygen converts carbon-containing materials (e.g. methane) into hydrogen (H₂), carbon monoxide (CO) and carbon dioxide (CO₂) without complete combustion (total oxidation).

After synthesis, the raw gas needs to be treated to remove impurities such as hydrogen chloride (HCl), hydrogen sulphide (H2S) and tar. The purified synthesis gas has properties comparable to those of natural gas and can be used as a fuel to generate energy. Part of the syngas is used to operate the gasification plant itself, while the remaining part is supplied to energy companies, which use the syngas primarily to generate electricity in gas-fired power plants.

The versatile applications of synthesis gas as an energy source and chemical raw material underline its key role in sustainable energy and chemical production. The further development of efficient and environmentally friendly synthesis gas processes is crucial for reducing fossil fuels and promoting a CO2-neutral economy.