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Recently, the Finance Minister in her budget speech formally announced the National Hydrogen Energy Mission which aims for generation of hydrogen from green power resources.

Background

• With this announcement, India has made an uncharacteristically early entry in the race to tap the energy potential of the most abundant element in the universe, hydrogen.
• The proposal in the Budget will be followed up with a mission draft over the next couple of months — a roadmap for using hydrogen as an energy source.
• The mission would have a specific focus on green hydrogen, dovetailing India’s growing renewable capacity with the hydrogen economy.

Hydrogen as an element

• The most common element in nature 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.

Its types as fuel

• 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.

Hydrogen for mobility

• While proposed end-use sectors include steel and chemicals, the major industry that hydrogen has the potential of transforming is transportation.
• This sector contributes a third of all greenhouse gas emissions, and where hydrogen is being seen as a direct replacement of fossil fuels, with specific advantages over traditional EVs.
• Hydrogen fuel cell cars have a near-zero carbon footprint.
• Hydrogen is about two to three times as efficient as burning petrol because an electric chemical reaction is much more efficient than combustion.

We already had H-CNG!

• In October 2020, 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 — directly from natural gas, without resorting to conventional blending.

Try this PYQ from CSP 2019:

In the context of proposals to the use of hydrogen-enriched CNG (H-CNG) as fuel for buses in public transport, consider the following statements :
1. The main advantage of the use of H-CNG is the elimination of carbon monoxide emissions.
2. H-CNG as a fuel reduces carbon dioxide and hydrocarbon emissions.
3. Hydrogen up to one-fifth by volume can be blended with CNG as fuel for buses.
4. H-CNG makes the fuel less expensive than CNG.
Which of the statements given above is/are correct?
(a) 1 only
(b) 2 and 3 only
(c) 4 only
(d) 1, 2, 3 and 4

Green hydrogen has specific advantages

1. One, it is a clean-burning molecule, which can decarbonize a range of sectors including iron and steel, chemicals, and transportation.
2. Two, renewable energy that cannot be stored or used by the grid can be channelled to produce hydrogen.

• This is what the government’s Hydrogen Energy Mission, to be launched in 2021-22, aims for.

Philosophy behind NHEM

• India’s electricity grid is predominantly coal-based and will continue to be so.
• 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 per cent 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.

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Back2Basics: 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 oxidizing agents through an oxidation-reduction reaction.
• Inside each individual fuel cell, hydrogen is drawn from an onboard pressurized 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.

  Issues with H-Fuel cells

• A big barrier to the adoption of hydrogen fuel cell vehicles has been a lack of fuelling station infrastructure.
• There are fewer than 500 operational hydrogen stations in the world today, mostly in Europe, followed by Japan and South Korea.
• Safety is seen as a concern. Hydrogen is pressurized and stored in a cryogenic tank, from there it is fed to a lower-pressure cell and put through an electrochemical reaction to generate electricity.
• 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.