H2 Knowledge Space: Hydrogen in general

The element hydrogen occupies the first place, top left, in the periodic table of the elements. This is because it consists of one proton and one electron and thus has the lowest atomic mass of all elements. As the most common element in the universe, hydrogen is involved in all organic compounds, among other things. On Earth, it occurs virtually exclusively in chemical compounds or as molecular hydrogen, H₂. Probably the best known chemical compound of hydrogen is water (H₂O). So-called hydrocarbons such as methane (CH₄), the main component of natural gas, and petroleum are other prominent representatives of the compounds of hydrogen. Carbohydrates such as glucose (C₆H₁₂O₆) also contain bound hydrogen. Thus, hydrogen is also a component of the carbon cycle and photosynthesis: all biomass contains hydrogen. In addition, more than half of all mineral compounds do as well contain hydrogen.

The chemical bond of molecular hydrogen has the most stable of all single bonds and thus stores a lot of energy. This makes H₂ an excellent energy carrier. The bound energy can be released by chemical or electrochemical processes. Living things create energy by digesting glucose, and petroleum and natural gas are usually burned to produce energy.

Hydrogen is used in various ways in industry. As the lightest element, its buoyancy kept many 19th century zeppelins in the air. Fuel cells use the  

energy of hydrogen to reliably supply electricity for space travel, in submarines, and increasingly for private applications such as passenger cars. Its widespread use makes it the starting point of many chemical process chains. By converting nitrogen to ammonia, NH₃ hydrogen is at the beginning of fertilizer and pharmaceutical production, thus enabling modern agriculture and medicine to the extent we know.  

In order to implement the energy transition, hydrogen plays a key role in at least two fields. First, the use of hydrogen must be made sustainable in those areas where it already plays a major role. As long as the production of hydrogen causes CO₂ emissions, large areas of industry will not be able to meet climate targets. On the other hand hydrogen as an energy carrier and storage medium is meant to replace other, climate-damaging, mostly fossil fuel options and to compensate for fluctuations in production in the renewable energy system.  

References:

1. Neugebauer, Reimund (2022): Wasserstofftechnologien. Berlin, Heidelberg: Springer Berlin Heidelberg.
2. https://www.bdew.de/energie/wasserstoff/flexible-herstellung-was-ist-wasserstoff-und-wie-wird-er-erzeugt/, bdew, 22.12.2022.