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. 
• In addition to this, the Indian Institute of Science (IISc) has developed an innovative technology to produce hydrogen from biomass.
• The process consists of two steps. In the first step, biomass is converted into syngas – a hydrogen-rich fuel gas mixture – in a novel reactor using oxygen and steam. In the second step, pure hydrogen is generated from syngas using an indigenously developed low-pressure gas separation unit.

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?

• India is set to hold the second edition of the International Conference on Green Hydrogen in New Delhi. 

https://www.newsonair.gov.in/india-to-hold-2nd-edition-of-international-conference-on-green-hydrogen-from-sept-11-13/