Hydrogen

Hydrogen is the chemical element with the symbol H and atomic number 1. It is the lightest element in the periodic table and the most abundant chemical substance in the universe, constituting roughly 75% of all baryonic mass. As an energy carrier and educt for reduction processes it is used for a number of different technologies including e.g. the methanol synthesis or the Fischer-Tropsch synthesis from synthesis gas after gasification of biomass, plastic and other organic materials.

Industrial production of hydrogen is mainly from steam reforming natural gas, and less often from more energy-intensive methods such as the electrolysis of water. Based on it's origin and production it can be devided in

• Green hydrogen produced by electrolysis of water with energy coming exclusively from electricity generated from wind, hydropower, photovoltaics and renewable resources in general. The energy used is stored in the hydrogen, except for small process-related losses. No carbon dioxide is produced during the production process.
• Grey hydrogen obtained from fossil fuels. In most cases, natural gas is converted into hydrogen and CO2 in a steam reformer. The resulting carbon dioxide is released into the atmosphere and thus increases the global greenhouse effect: the production of one tonne of hydrogen produces about 10 tonnes of CO2. If the methane used comes from biogas and the steam reformer is operated with renewable energies, then the process is CO2-neutral in its overall balance and the product is green hydrogen.
• Blue hydrogen, which is grey hydrogen whose carbon dioxide is captured and stored as it is produced. This is called CCS - Carbon Capture and Storage.
• Turquoise hydrogen produced by the thermal splitting of methane (methane pyrolysis). Because the reaction takes place in the absence of oxygen, no carbon dioxide is produced, but solid carbon. For the process to be truly CO2-neutral, the high-temperature reactor must be heated with renewable energy, but still the produced carbon is coming from fossil sources.

Most hydrogen is used near the site of its production, the two largest uses being fossil fuel processing (e.g., hydrocracking) and ammonia production, mostly for the fertilizer market.