Context:India has made an uncharacteristically early entry in the race to tap the energy potential of the most abundant element in the universe, hydrogen. India has announced a National Hydrogen Mission.

Details:

• And while proposed end-use sectors include steel and chemicals, the major industry that hydrogen has the potential of transforming is transportation.
• Delhi became the first Indian city to operate buses running on hydrogen spiked compressed natural gas (H-CNG) in a six-month pilot project.
• The buses will run on a new technology patented by Indian Oil Corp for producing H-CNG — 18 per cent hydrogen in CNG.

Why hydrogen — and its types:

• 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.
• 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, electricity generated from renewable energy is used to split water into hydrogen and oxygen.

The case for green hydrogen:

• Green hydrogen has specific advantages.
• One, it is a clean burning molecule, which can decarbonise a range of sectors including iron and steel, chemicals, and transportation.
• Two, renewable energy that cannot be stored or used by the grid can be channelled to produce hydrogen.
• India’s electricity grid is predominantly coal-based and will continue to be so, thus negating collateral benefits from a large-scale EV push — as coal will have to be burnt to generate the electricity that will power these vehicles.
• In several countries that have gone in for an EV push, much of the electricity is generated from renewables — in Norway for example, it is 99 percent from hydroelectric power.
• Experts believe hydrogen vehicles can be especially effective in long-haul trucking and other hard-to-electrify sectors such as shipping and long-haul air travel.
• Using heavy batteries in these applications would be counterproductive, especially for countries such as India, where the electricity grid is predominantly coal-fired.

How hydrogen fuel cells work?

• Hydrogen is an energy carrier, not a source of energy.
• Hydrogen fuel must be transformed into electricity by a device called a fuel cell stack before it can be used to power a car or truck.
• A fuel cell converts chemical energy into electrical energy using oxidising agents through an oxidation-reduction reaction.
• Fuel cell-based vehicles most commonly combine hydrogen and oxygen to produce electricity to power the electric motor on board. Since fuel cell vehicles use electricity to run, they are considered electric vehicles.
• Inside each individual fuel cell, hydrogen is drawn from an onboard pressurised tank and made to react with a catalyst, usually made from platinum.
• As the hydrogen passes through the catalyst, it is stripped of its electrons, which are forced to move along an external circuit, producing an electrical current.
• This current is used by the electric motor to power the vehicle, with the only byproduct being water vapour.

The problem of critical mass:

• Despite its promise, hydrogen technology is yet to be scaled up. Tesla CEO Elon Musk has called fuel cell technology “mind- bogglingly stupid”.
• A big barrier to the adoption of hydrogen fuel cell vehicles has been a lack of fueling station infrastructure — fuel cell cars refuel in a similar way to conventional cars, but can’t use the same station.
• Safety is seen as a concern. Hydrogen is pressurised and stored in a cryogenic tank, from there it is fed to a lower-pressure cell and put through an electro-chemical reaction to generate electricity.

Conclusion:

Scaling up the technology and achieving critical mass remains the big challenge. More vehicles on the road and more supporting infrastructure can lower costs. India’s proposed mission is seen as a step in that direction.

https://indianexpress.com/article/explained/electric-vehicle-technology-hydrogen-car-national-hydrogen-mission-7193217/

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