Traditionally a slow mover in frontier electric vehicle (EV) technologies, India has made an uncharacteristically early entry in the race to tap the energy potential of the most abundant element in the universe, hydrogen. Less than four months after the United States Department of Energy announced an investment up to $100 million in hydrogen production and fuel cell technologies research and development, India has announced a National Hydrogen Mission.
And while proposed end-use sectors include steel and chemicals, the major industry that hydrogen has the potential of transforming is transportation — which 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.
A handful of mobility-linked pilots are already under way.
In October, 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.
Power major NTPC Ltd is operating a pilot to run 10 hydrogen fuel cell-based electric buses and fuel cell electric cars in Leh and Delhi, and is considering setting up a green hydrogen production facility in Andhra Pradesh.
IOC is also planning to set up a dedicated unit to produce hydrogen to run buses at its R&D centre in Faridabad.
As a supporting regulatory framework, the Ministry of Road Transport and Highways late last year issued a notification proposing amendments to the Central Motor Vehicles Rules, 1989, to include safety evaluation standards for hydrogen fuel cell-based vehicles.
Why hydrogen — and its types
Hydrogen’s potential as a clean fuel source has a history spanning nearly 150 years. In 1874, science fiction writer Jules Verne set out a prescient vision in The Mysterious Island — of a world where “water will one day be employed as fuel, that hydrogen and oxygen which constitute it, used singly or together, will furnish an inexhaustible source of heat and light, of an intensity of which coal is not capable”.
In 1937, the German passenger airship LZ129 Hindenburg used hydrogen fuel to fly across the Atlantic, only to explode while docking at Naval Air Station Lakehurst in New Jersey, killing 36 people. In the late 1960s, hydrogen fuel cells helped power NASA’s Apollo missions to the moon.
After the oil price shocks of the 1970s, the possibility of hydrogen replacing fossil fuels came to be considered seriously. Three carmakers — Japan’s Honda and Toyota, and South Korea’s Hyundai — have since moved decisively in the direction of commercialising the technology, albeit on a limited scale.
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. 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.
This is what the government’s Hydrogen Energy Mission, to be launched in 2021-22, aims for. 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 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.
How hydrogen fuel cells work
South Korea and Japan especially, are focussed on moving their automotive markets to hydrogen, and the potential of the fuel cell. What is a fuel cell?
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.
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.
FCEVs and other EVs
Electric vehicles (EVs) are typically bracketed into four broad categories:
* Conventional hybrid electric vehicles or HEVs such as Toyota Camry combine a conventional internal combustion engine system with an electric propulsion system, resulting in a hybrid vehicle drivetrain that substantially lowers fuel usage. The onboard battery in a conventional hybrid is charged when the IC engine is powering the drivetrain.
* Plug-in hybrid vehicles or PHEVs such as the Chevrolet Volt too have a hybrid drivetrain that uses an IC engine and electric power for motive power, backed by rechargeable batteries which can be plugged into a power source.
* Battery powered electric vehicles or BEVs such as Nissan Leaf or Tesla Model S have no IC engine or fuel tank, and run on a fully electric drivetrain powered by rechargeable batteries.
* Fuel cell electric vehicles or FCEVs such as Toyota’s Mirai, Honda’s Clarity and Hyundai’s Nexo use hydrogen gas to power an on-board electric motor. FCEVs combine hydrogen and oxygen to produce electricity, which runs the motor. Since they’re powered entirely by electricity, FCEVs are considered EVs, but unlike BEVs, their range and refuelling processes are comparable to conventional cars and trucks.
The major difference between a BEV and a hydrogen FCEV is that the latter enables a refuelling time of just five minutes, compared to 30-45 minutes charging for a BEV. Also, consumers get about five times better energy storage per unit volume and weight, which frees up a lot of space for other things, while allowing the rider to go farther.
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”.
Globally, there were under 25,000 hydrogen fuel cell vehicles on the road at the end of 2020; by comparison, the number of electric cars was 8 million.
A big barrier to the adoption of hydrogen fuel cell vehicles has been a lack of fuelling station infrastructure — fuel cell cars refuel in a similar way to conventional cars, but can’t use the same station. There are fewer than 500 operational hydrogen stations in the world today, mostly in Europe, followed by Japan and South Korea. There are some in North America.
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. Hyundai and Toyota say safety and reliability of hydrogen fuel tanks is similar to that of standard CNG engines.
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.
Toyota's revamped Mirai hydrogen fuel cell car, showing the engineering under the hood, on display at its launch event in Tokyo in December 2020. (Photo: Reuters) 
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