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Electrolysis

In a time when we’re worried more and more about environmental issues, we need to move towards using cleaner and eco-friendly energy. Electrolysis is one technology that could be a game-changer. It helps create green hydrogen, a form of energy that emits no greenhouse gas.

Electrolysis is a technique that uses electrical power to break down water particles into hydrogen and oxygen gases. When this method is fueled by renewable sources, it can generate green hydrogen. This green hydrogen can subsequently be used as an eco-friendly energy medium.

Here is a comprehensive guide on Electrolysis, a pivotal technology behind the surge of the green hydrogen movement.

Types Of Electrolysis

Electrolysis, an industrial process, uses three main technologies: Solid-Oxide Electrolysis Cell (SOEC), alkaline electrolysis, and polymer electrolyte membrane (PEM) electrolysis. SOEC operates at high temperatures and uses steam. Both alkaline and PEM electrolysis operate at lower temperatures and use liquid water.

PEM Electrolysis

  • PEM electrolysis separates hydrogen and oxygen gases using a solid polymer electrolyte membrane.
  • This membrane is important for making green hydrogen because it conducts protons very well.
  • Another key feature of this membrane is that it blocks gases from mixing with each other.
  • The temperature for this process is quite low, ranging between 50-80°C.
  • These systems are known for their quick response time.
  • One of the advantages of PEM electrolysis systems is their compact and modular design. This makes them ideal for inconsistent renewable energy sources like wind and solar.
  • The systems can easily adjust their output to match changes in energy supply.
  • However, PEM electrolysis systems can be costlier because the membrane material is expensive.
  • Despite the cost, the market for PEM electrolysis is strong and well-established.
  • It’s particularly beneficial for applications that need very pure hydrogen, such as fuel cell vehicles and pipelines.
  • As the adoption of renewable energy grows, the market for PEM electrolysis is expected to expand.

SOEC Electrolysis

  • SOEC electrolysis uses a solid oxide ceramic electrolyte and operates at high temperatures, usually around 675°C to 825°C.
  • The high operation temperature makes the water electrolysis reaction easier, resulting in less power consumption for every unit of hydrogen produced.
  • Compared to PEM and alkaline electrolysis, SOEC is more efficient. It’s a good fit for hydrogen production on a large scale, particularly for industries like steel, ammonia, and chemical production and refining.
  • According to the International Renewable Energy Agency (IRENA), SOEC electrolyzers are 10-26% more efficient (in terms of kWh per kg of hydrogen produced) than alkaline and PEM technologies.
  • SOEC electrolysis is quite new compared to PEM and alkaline in many applications. But it shows great potential for industrial uses and energy storage, especially where there are high-temperature heat sources and large amounts of heat waste.

Also Read | National Green Hydrogen Mission

Alkaline Electrolysis

  • Alkaline electrolysis involves the use of an alkaline solution, typically potassium hydroxide.
  • Its core function is to promote ion exchange, which produces hydrogen.
  • This method works under moderate temperature conditions.
  • It is a well-established technique, utilised in various industries for many years.
  • Among its advantages, alkaline electrolysers are cost-effective and have a proven track record.
  • On the other hand, they have lower efficiency rates and slow response to load shifts when compared to PEM electrolysis.
  • While competitive within specific industries, alkaline electrolysis might struggle with efficiency issues.
  • This method also faces potential difficulties in integrating with renewable energy sources.

Opportunity For India

  • Electrolyser costs need to be cut to produce competitively priced hydrogen.
  • India is already a global leader in the levelised cost of energy for renewable sources like solar and wind.
  • There’s a global tendency towards improving electrolyser design and developing new techniques.
  • By creating a local electrolyser production sector, India can leverage its engineering expertise and position itself as a global player in this field.
  • This would also allow the country to benefit financially from the transition to clean energy.
  • Green hydrogen pricing will ultimately depend on energy and electrolyser costs.
  • Other financial strategies can also help reduce manufacturing costs.
  • Achieving a levelised cost of hydrogen of around $3.2 per kg could be possible by reducing duty costs, lowering the goods & services tax, and cutting transmission and distribution fees.
  • The Union Ministry of Power has already exempted interstate transmission system costs for electricity from renewable sources like solar and wind.
  • The exemption of the costs has been covered for the programmes to be installed from June 30, 2025 onwards and includes the pumped hydroelectricity and battery energy storage projects.
  • Cutting down such costs for hydrogen production using renewable energy sources would help develop green hydrogen financials.
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