Science and Technology

Green hydrogen spawns new industry

M Ramesh | Updated on September 13, 2021

MSMEs can ride the opportunity that electrolyser manufacturing presents, provided they keep pace with technology

It is ancient wisdom that ‘the old order changeth, yielding to new’ and we are seeing that in the economy today. Carbonaceous industries such as coal and oil are on the way out, yielding place to newer industries such as electric vehicles.

One such newcomer industry has the potential to become very big in India, enabling the country to leapfrog to a vanguard position in this technology.

We are talking of the ‘electrolyser industry’. Today, the accent is on green hydrogen (g-hydrogen), which is hydrogen produced without carbon footprint. The most favoured process for producing g-hydrogen is using electricity to split water into hydrogen and oxygen. The machine that does this is the ‘electrolyser’.

The manufacture of electrolysers is a huge emerging business opportunity — but one that requires the industrialist to keep a sharp eye on the technology.

In India, according to a recent study by Delhi-based energy think tank Council for Energy, Environment and Water (CEEW), the current consumption of hydrogen is about 5.6 million tonnes (mt), but almost all of it comes from the ‘steam methane reforming’ process, which emits the dreaded greenhouse gas carbon dioxide. Another 1.9 mt of hydrogen is embedded in the methanol and fertilisers that the country imports. So, today, if the country were to replace all the hydrogen in use with green hydrogen, the demand would be 7.5 mt per annum. To produce this much, you would need electrolyser capacity of 130-140 GW. Roughly, the production of 1 mtpa of green hydrogen requires 18 GW of electrolyser capacity married to 26 GW of solar power. Today’s electrolysers sell at $250-300 a kW, but the prices are expected to fall by about 40 per cent over the next five years, according to CEEW.

However, it is unrealistic to think that all the hydrogen in demand could be switched over to green hydrogen. We don’t know what the Indian demand for green hydrogen will be, because much depends on what the government does in terms of mandating its use (‘green hydrogen purchase obligation’). But we do know that the government is serious about this and, consequently, the demand will be large.

If the government mandates ‘10 per cent obligation’, that is demand for 0.56 mtpa of green hydrogen straightaway. But not only would the government raise the obligation level, with an increase in economic activity the base on which the obligation is applied would also go up.

The industry is taking note of this. A US company, Ohmium, has announced that it would begin manufacturing electrolysers in Bengaluru. Reliance, Tata Steel and L&T are also interested; Quantum learns that these companies are in talks with the government-owned research body National Chemical Laboratories (NCL), Pune, for technology. As the CEO and co-founder of Ohmium Arne Ballantine pointed out to Quantum, the manufacture of electrolysers presents a big opportunity to MSMEs to participate in the supply chain.

Picking the right technology

As the industry dives into electrolyser manufacturing, it faces the ticklish question of the choice of technology. Today, there isn’t much to choose from — the age-old ‘alkaline’ technology is vacating the space in favour of the safer and more energy-efficient ‘proton exchange membrane’ (PEM). However, PEM, which requires highly acidic membranes (pH 1), calls for electrodes made of expensive metals (iridium, platinum, rubidium, rhodium); if cheap metals as electrodes are used, they will corrode in no time. Also, PEM slaps a bigger maintenance bill on the user.

An emerging technology, anode exchange membrane (AEM), holds promise to overcome PEM’s challenges.

In a PEM, water fed into the anode (positive) side is split into hydrogen ions (protons), electrons and oxygen. The protons pass through the membrane to the cathode side, where they join with electrons from the supplied electricity to become hydrogen. In an AEM, water splits into a negatively charged hydroxyl ion and hydrogen. The hydroxyl ion passes through the membrane, where it becomes water and oxygen. The membrane doesn’t have to be acidic. As such, while AEM too consumes roughly the same energy as PEM — 50-55 kWhr per kg — it can use electrodes made of cheaper metals such as nickel.

NCL has achieved success in AEMs. “In our lab, transition metals (such as nickel, cobalt, iron) are working better than precious metals,” says Dr Kaliaperumal Selvaraj, who heads the research. However, AEM is a yet-to-mature technology. “There are lots of unknowns,” notes Pashupathy Gopalan, an investor of Ohmium. For example, in a PEM you can compress hydrogen, which is a very light gas, into a high-pressure chamber electro-chemically — the electricity ‘pulls’ hydrogen through the membrane into the high-pressure chamber. But in an AEM you would need mechanical compression, which means more energy and moving parts. Also, AEM is yet to be proven on a large scale.

So, should one wait for AEM to mature or go with PEM? Experts say there is no need to wait for AEM, as one can always switch over to it from PEM. “The science is different, but the design is similar,” says Selvaraj.

He believes that NCL has designed a good AEM contrivance. AEM presents India an opportunity to become a global leader in this area, as research here is not lagging behind any other country.

Published on September 12, 2021

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