Syngas is a mixture of mostly hydrogen, carbon monoxide and carbon dioxide. Depending on the amount of hydrogen, syngas has roughly 25% the energy density of natural gas.

Syngas is one of the basic building blocks of the chemical industry, and can be used as a feedstock to produce products such as hydrogen, ammonia, ethanol and methanol.

Syngas can also be used to produce fuels such as in a Fischer-Tropsch process to produce synthetic diesel or ethanol, or by conversion into methane and dimethyl ether in catalytic reactions.