Green Hydrogen Electrolyzers

According to India’s G20 Sherpa Amitabh Kant, India can transform and become the global leader, exporter, producer of electrolyzer and global champion of green hydrogen.

About Green Hydrogen Electrolysers –

• Hydrogen electrolysers are devices that use electricity to split water into hydrogen and oxygen.
• When electricity input to the electrolyser is obtained from renewable sources like wind and solar, then the hydrogen produced is called green hydrogen.
• Typically, electrolysers consume 50-55 kilowatt-hours or units of electricity to produce one kilogram of hydrogen.
• Electrolysers produce hydrogen at about 50-90 degree Celsius and at a pressure of 30-50 bar.
• Electrolysers are commercially available at a size of a few kilowatts (kW) to megawatts (MW).

What are the different electrolyser technologies?

• There are various electrolyser technologies available currently.
• Alkaline electrolysers and polymer electrolyte membrane (PEM) electrolysers are commercially available technologies.
• Alkaline electrolysers use liquid alkaline electrolyte solution of sodium or potassium hydroxide while PEM electrolysers are based on solid polymer membrane.
• In addition to these, there are other proprietary technologies like electrochemical, thermally-activated chemical (E-TAC) and anion exchange membrane (AEM) that claim to be more efficient than existing technology options.

What is green hydrogen?
Green hydrogen is hydrogen gas produced through electrolysis of water — an energy intensive process for splitting water into hydrogen and oxygen— using renewable power to achieve this.

Types of Hydrogen –

• Hydrogen may be the most common element in nature but it is not found freely. Hydrogen exists only combined with other elements, and has to be extracted from naturally occurring compounds like water (which is a combination of two hydrogen atoms and one oxygen atom). Although hydrogen is a clean molecule, the process of extracting it is energy-intensive.
  • • The sources and processes by which hydrogen is derived, are categorised by colour tabs. Hydrogen produced from fossil fuels is called grey hydrogen; this constitutes the bulk of the hydrogen produced today.
    • Hydrogen generated from fossil fuels with carbon capture and storage options is called blue hydrogen;
    • Hydrogen generated entirely from renewable power sources is called green hydrogen.
    • In the last process (green hydrogen), electricity generated from renewable energy is used to split water into hydrogen and oxygen.