Science and Technology

Hydrogen mission: Thrice as nice

M Ramesh | Updated on February 14, 2021

All aboard: The long-awaited National Mission on Hydrogen looks imminent, given its mention in the Budget speech   -  ISTOCK.COM

To power its economy with pocket-friendly green hydrogen, India need look no further than its farmlands

Biezel Green Energy (BGE) is not a known name, except perhaps in the vicinity of Varanasi, where the company has a production unit. But what the company is doing may be a good indicator of the shape of things to come, in the hydrogenisation of the Indian economy.

BGE was set up three years ago by two scientists from Indian Institute of Science, Bengaluru — Preetam Singh and Konda Shiva; both had done their post-doctoral work under Prof John Goodenough of University of Texas, Austin, the 2019 chemistry Nobel laureate. BGE produces hydrogen and other fuels from biomass, using a technology invented by Singh and Shiva. They call it ‘thermally accelerated anaerobic digestion’, or TAD.

Singh tells Quantum that the TAD reactors can process 1,500–2,000 kg of biomass over 36 hours to produce hydrogen, methane, bio-coal and liquefied natural gas. One kg of biomass splits into 35-40 grams of hydrogen, 140-170 grams of methane, 280-300 grams of bio-coal — of a high calorific value of 6,500–8,000 kCal/kg, depending on the biomass used.

But, notably, the process can produce hydrogen at less than $5 a kg — a globally targeted cost.

Singh, who also teaches at IIT-BHU, Varanasi, is convinced that the biomass route of hydrogen production is the way to go.

This resonates well with the views of Dr SSV Ramakumar, Director – R&D, Indian Oil Corporation (IOC), as the company is angling for a big role in hydrogen. Ramakumar, too, has told Quantum that biomass gasification is “the only way” to produce green hydrogen for $4-5 a kg.

Even as the long-awaited National Mission on Hydrogen looks imminent, given its mention in the finance minister’s budget speech, there is a hot debate over whether or not hydrogen can compete with batteries, as battery costs are plummeting. (Missing in the debate is the point that the battery is not as green as green hydrogen, unless its electricity comes from renewable sources — the world is still a long way from renewable energy becoming the premier supplier of electricity.)

Grey hydrogen, which comes from the steam methane reforming (SMR) route, costs $2-3 a kg (not counting costs of purification and transportation). But that is not quite what the world wants, because SMR also produces carbon dioxide. (Carbon in natural gas and oxygen in water combine to form carbon dioxide, giving off hydrogen.) VK Saraswat, Member, Niti Aayog, the Indian government’s think-tank, sees “no long-term role for SMR”.

Still, the debate is between battery and green hydrogen, and the market broadly favours the former.

There are other ways of making hydrogen — by splitting water (electrolysis), reforming methanol and ammonia, and using microbes to convert biomass into the gas. As things stand today, these technologies are neither mature nor cheap. Electrolysis, for example, is an inefficient route — it takes much energy to break the tight bond between hydrogen and oxygen atoms. Pulling hydrogen atoms out of carbon-hydrogen compounds of natural gas or biogas needs lesser energy. Admittedly, a lot of research is on in electrolysis and a winner could emerge. For example, scientists are researching electrocatalysts to improve the process. Researchers at the Centre for Nano and Soft Matter Sciences, Bengaluru, have recently synthesised a ‘coordinated polymer’ (cage-like structure) catalyst made with palladium and benzene tetramine [Pd(BTA)]. Then, there are photoelectrochemical methods of splitting water in light and photobiological water splitting using mircobes, to produce hydrogen. But these technologies are a good distance away. In any case, electrolysis is a bit roundabout because it is ‘electricity-hydrogen-fuel cell-vehicle’; on the other hand, ‘electricity-battery-vehicle’ is a step less.

BGE’s experience shows that the biomass gasification route is the cheapest. At ₹5 a kg for 1,500 kg of biomass (that BGE pays) and ₹7 a kWhr for 900 kWhr of electricity, the raw material cost per kg of hydrogen for a 60-kg batch yield works out to ₹230 ($3); add other variable costs and overheads, you still end up around $5 — even without counting the value of by-products. This appears too fantastic, when the market price of ultra-high pure ‘five-nine’ (99.999 per cent) hydrogen is around ₹2,000 a kg; but Singh insists this costing is actual, not theoretical. BGE is already selling hydrogen to NTPC, where it is used as a coolant.

Ramakumar says IOC is “betting heavily on biomass gasification”. Incidentally, IOC is in talks with BGE for joint work on hydrogen. “If you want to marry the hydrogen economy with the agrarian economy, biomass-based hydrogen pathways hold a greater promise,” says Ramakumar, pointing to the potential of raising farmers’ income.

It is sensible to have well distributed production of hydrogen — imagine transporting the inflammable fuel across the country! Hydrogen is a tough brat to store (see ‘Tough cylinder’). You must make the gas where you can quickly use. Hence, again, the biomass pathway.

So, by the looks of it, India’s hydrogen will come out of its vast agricultural fields. If this happens, it will resolve three problems with one solution. First, it can raise farm incomes. Singh says a farmer will get ₹10,000 per acre by selling his agri-residue. Second, it can be the solution to stubble burning. Finally, you can have green hydrogen at pocket-easy prices.

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Published on February 14, 2021

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