IIT Madras scientists develop prototype to use seawater for green hydrogen production

Subject :Science and technology

Section: Msc

Context:

IIT-Madras researchers have developed components for an alkaline water electrolyser that can use seawater directly to make green hydrogen.

Details:

The technology is simple and cost-effective.
This is proposed as an alternative to the use of freshwater which is currently the key input for green hydrogen production.
The technology is still nascent and will take a few years to be commercially deployed, if proven successful.
India is ambitious about producing green hydrogen, but the scarcity of the critical input, freshwater, is a challenge.
Along with India, globally there are efforts to study and develop technologies to tap the abundant seawater for green hydrogen production.

What is Green Hydrogen?

Green hydrogen is a type of hydrogen that is produced through the electrolysis of water using renewable energy sources such as solar or wind power.
The electrolysis process splits water into hydrogen and oxygen, and the hydrogen produced can be used as a clean and renewable fuel.

Green Hydrogen Mission:

India’s National Green Hydrogen Mission, which aims to boost India’s green hydrogen production and ecosystem, has set a target to build capabilities for producing at least five Million Metric Tonnes (MMT) GH2 per annum by 2030.
However, the government also recognises its impact on freshwater – one of the key inputs for GH2 production – so it is pushing to maximise industrial and municipal wastewater use for hydrogen production wherever feasible.

The traditional method of green hydrogen production:

Green hydrogen is produced from pure water through a process known as electrolysis, which uses an electric current from renewable energy to split water into its component molecules, hydrogen and oxygen, using a device called an electrolyser.
In effect, green hydrogen is “clean” as it has low carbon emissions and is expected to play a prominent role in decarbonising heavy industries, including oil refineries, steel mills and fertiliser plants.
The traditional electrolysers, however, are designed to work with pure water, and scaling up the GH2 process could exacerbate global freshwater shortages.

New technology:

The new technology and research from IIT Madras aim to tap into the abundantly available seawater directly to make GH2.
The researchers used a carbon-based support material for the electrodes instead of metals to almost eliminate the possibility of corrosion.
There are two ways in which seawater can be used to replace fresh water for the production of GH2:

Desalination of seawater to produce fresh water to remove the salt before the water flows to conventional electrolysers and
The use of seawater directly for the electrolysis process.

Drawbacks:
- According to UNEP, about 1.5 litres of liquid polluted with chlorine and copper are created for every litre of potable water produced through desalination. When pumped back into the ocean, the toxic brine depletes oxygen and impacts organisms along the food chain.

Other types of Hydrogen: