Green RIL. Reliance’s green gambit more directional, less concrete

Reliance Industries’ ₹75,000 crore green pivot sounds like a risky bet, at least to some.

Of the four elements of Chairman Mukesh Ambani’s announcement, only ‘solar PV’ is an idea whose time has come; the others—green hydrogen, advanced energy storage and fuel cells—are still some distance away.

Manufacturing PV modules is an obvious choice, given the government’s push for the local manufacture of the product in terms of duty barriers against imports and subsidies. Likewise, large solar power generating units, even if as large as 100GW, are also the order of the day.

However, the other three make the eyebrow go up.

Take green hydrogen, for instance. ‘Green hydrogen’ refers to producing the gas from renewable sources. Ambani has spoken of building an electrolyzer—a machine in which electrolysis of water happens. It is basic science that electricity splits water into hydrogen and oxygen. Yet, the world has not rushed into this route to produce hydrogen, simply because it is not economical.

“Electrolysis of water is the worst way of producing hydrogen,” says Prof Preetam Singh of IIT BHU, who has worked extensively on hydrogen. (This was a general comment, not about Reliance’s plans.)

The bonds between hydrogen and oxygen atoms are very tight and it takes a lot of energy to break them. Roughly, it takes 39 kWhr of electricity to produce one kg of water, in a 100 per cent efficient electrolyzer. In practical terms, you would need 50 units of electricity to produce a kg of hydrogen, not counting the energy consumed by the plant, such as for pumps.

It is argued that cheap hydrogen can be produced using solar energy. This argument presupposes access to solar energy for as low as ₹2 - 2.50. Solar prices are set to go up because there is going to be a 40 per cent duty on imported modules; locally produced modules will not come cheap either. Besides, solar electricity prices depend on the location of the plant—you don’t get it cheap everywhere. Nor do you get it all the time, so you would need a backup. Furthermore, if you already have electricity, why convert it into hydrogen at all, unless you know what to do with it? And then, there are costs of storing and transporting hydrogen. However, it might make sense if the gas is used to produce methanol, which can be mixed with petrol or made into di-methyl ether (DME) and used in diesel engines.

Putting money behind electrolysers might mean missing out on other, emerging technologies for producing hydrogen, such as coal or biomass gasification (both coal and biomass are abundantly available in India); or using metals to produce the gas. Prof Vivek Polshettiwar of TIFR has developed a process of producing hydrogen economically by reacting Magnesium with water in the presence of carbon dioxide. Prof Satya Chakravarthy of IIT Madras has developed another method that gives out hydrogen when aluminium is reacted sea water. (There are many aspects of the process, such as recovery of the metal, that make it viable.) These are promising technologies.

Ambani has also spoken about building a fuel cell factory for converting hydrogen into motive and stationary power. Now, a fuel cell converts hydrogen into electricity. It is not clear why one would start with electricity to produce hydrogen and then use the hydrogen to produce electricity, in a stationary situation. As for fuel cells in transportation, it is clearly not economical. Fuel cells, known for a long time, are still a long way from maturing as a transport fuel.

Advanced storage batteries

Electrochemical storing of energy has made rapid progress in the last decade, with storage costs coming down. What used to be $1,100 per kWhr in 2010 was $140 in 2020. But the technology is changing so fast that the peril of obsolescence is real. The world is moving towards technologies such as solid electrolytes and cathode-less batteries; air batteries (lithium-air, sodium-air etc.) are lurking on the horizon. These promise to be really low cost.

Reliance has not revealed the details of its plans. It is most probably assessing the various horses to bet on the right one. At the moment therefore, one must assume that Ambani’s announcement of Thursday was more directional, less concrete.

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