The lesson "Hydrogen" focuses on the production of hydrogen.

There are various ways to produce hydrogen. Hydrogen can be generated from either fossil or renewable primary energy sources. Today, most hydrogen is produced from non-renewable energy (mainly natural gas, but also from oil or coal) through reforming processes (e.g., steam reforming, partial oxidation, or autothermal reforming). The renewable energy sources available for hydrogen production include biomass resources, wind, water, and solar energy.

Hydrogen is used in the refinery industry for hydrocracking and desulfurization, as well as in the chemical industry (fertilizer production). It is also used as an industrial gas in metal production, methanol production, food processing, and the electronics industry. The hydrogen market is a fairly large market with an emerging industry and supply chain (IEA Hydrogen, 2017).

1. Biobased hydrogen production

Hydrogen production from biogenic resources Hydrogen produced from biomass explicitly falls under biofuels, not electricity-based fuels. The description of biogenic production options is included here merely for completeness. Hydrogen can be generated from biogenic resources through thermochemical or biochemical processes. The application of such processes for hydrogen production is currently negligible but is expected to increase in the future.

Gasification is one of the thermochemical processes suitable for producing hydrogen from woody biomass resources from forests, plantations, or uncontaminated waste wood.

Biochemical routes use various microorganisms to either ferment biomass or split water into oxygen and hydrogen through biophotolysis (e.g., with algae or cyanobacteria). Biofermentation can occur via dark fermentation with heterotrophic bacteria or via photofermentation with photobacteria. All these process routes would require large amounts of biomass for large-scale hydrogen production.