- Hydrogen is a colourless, odourless, tasteless, non-toxic and highly combustible gaseous substance. It is also the lightest, simplest and most abundant member of the family of chemical elements in the universe.
- Hydrogen is a clean fuel and an efficient energy carrier. It is emerging as an important source of energy since it has zero carbon content in contrast to hydrocarbons which have net carbon content between 75 and 85 per cent. When burnt, Hydrogen produces water as a by-product and is, therefore, environmentally benign.
- It has huge potential in the transportation sector as a direct replacement to fossil fuels, as it is possible to store hydrogen on-board.
How is Hydrogen Generated?
- Hydrogen (H2) is one of the most abundant elements available on earth. However, it is not found in elemental form.
- The richest source of hydrogen is water. Hydrogen is also found in organic compounds and fossil fuels like petroleum, natural gas, coal and biomass.
- Hydrogen for commercial use is produced from catalytic steam reforming of natural gas, naphtha and other hydrocarbons, partial oxidation of hydrocarbons, gasification of coal and electrolysis of water.
- The energy industry refers to different “types” of hydrogen to differentiate how it is produced.
What is Green Hydrogen?
- Green hydrogen is produced through electrolysis using renewable sources of energy such as solar, wind or hydel power. It is produced by splitting water into hydrogen and oxygen using renewable electricity.
- That makes green hydrogen the cleanest option – hydrogen from renewable energy sources without CO2 as a by-product.
Other Types of Hydrogen
- Hydrogen can be ‘grey’, ‘brown’, ‘Turquoise’ and ‘blue’ too.
- The vast majority of industrial hydrogen is currently produced from natural gas through a conventional process known as steam methane reforming (SMR). The standard SMR process produces what is known as Grey Hydrogen and has the major disadvantage of releasing large quantities of by-product CO2 into the atmosphere – the main culprit for climate change.
- Grey hydrogen has increasingly been produced also from coal, with significantly higher CO2 emissions per unit of hydrogen produced so much that it is often called brown or black hydrogen instead of grey.
- Blue hydrogen, too, is produced using electricity generated by burning methane or coal but with technologies to prevent the carbon released in the process from entering the atmosphere;
- Turquoise hydrogen is made using a process called methane pyrolysis to produce hydrogen and solid carbon. As a result, there is no requirement for carbon capture and storage (CCS) and the carbon can even be used in other applications. Where the electricity driving the pyrolysis is renewable, the process is zero-carbon.
Why in News?
- In the run-up to the 18th G20 Summit, a day-long conference on “Green Hydrogen Pilots in India” was held in New Delhi.