Green hydrogen seems to be the centre of action as the clean fuel for enabling net zero emission. As hydrogen has a much higher energy density than alternative fuel choices like propane or gasoline, it can serve as a valuable energy source in industry and the transport sector. Also, as it has a zero-carbon footprint post combustion, it is an ideal choice for adopting low carbon pathways.
Similar hype existed for biofuel in India a decade-and-a-half back. We are still struggling to meet the 20 per cent blending target and the goal posts are being shifted time and again. It is worthwhile to recapitulate the mistakes India made in its biofuel transition.
Most countries which have been successful in promoting biofuel have banked on some crops as feedstock. Most also have undertaken genetic engineering on the crops so that the yield is maximised. Take the case of Brazil. Most of its ethanol is produced from sugarcane directly for efficient extraction. By contrast, India uses by-products (molasses) from sugar production or damaged food crops to produce ethanol. This is not an efficient process. Of course, the sugar producers get better price for their by-products.
It is best India identifies feedstock, and undertakes genetic engineering on the plants concerned if it plans to use biofuel in a big way in the transportation sector. The use of used oil and crop residue can at best supplement biofuel production, but can never fulfil the scale target India needs if it wants to replicate Brazilian experiment with biofuel. Also, India lacks R&D investment in fourth generation biofuel (algae based). A laissez faire approach without R&D interventions has not yield much in respect of maturing of the sector.
Hydrogen transition
The development of green hydrogen currently rests crucially on availability of green power and access to clean water. Like other countries, India is banking on green power like solar or wind for production of hydrogen by electrolysis of water. However, only a few western and northern States are making significant progress in the development of renewable energy. The biggest problem is that the States which are production centres of green electricity are the very States which are water-stressed.
India’s groundwater use is estimated at roughly one-quarter of the global usage, surpassing that of China and the US combined. With farmers provided with electricity subsidies for groundwater pumping, the water table has seen a drop of up to four meters in some parts of the country.
This unfettered draining of groundwater sources has accelerated over the past two decades. The Ministry of Jal Shakti (MoJS) has identified 255 out of total 788 districts as water stressed districts. Supporting 16 per cent of the world’s inhabitants is daunting enough, but it is even more so when one recognises that India only possesses 4 per cent of the world’s fresh water. Clearly, India has to adopt water efficient agricultural practices to free the scarce resource and augment capacity of green hydrogen. Saving of water from agriculture won’t happen without strong policy intervention and incentives. Should government have a policy to decide whether a hydrogen plant will be built in water stressed blocks?
Seawater is an abundant resource, therefore producing green hydrogen from it via electrolysis can help meet India’s energy challenge. Some of the States are building off-shore wind/solar farms. So, use of seawater for producing hydrogen is a natural choice. Moreover, solar power capacity is fast getting developed in States like Rajasthan and Gujarat where getting cheap freshwater is a dream. Hence, seawater can be the key ingredient for producing hydrogen.
Controlling corrosion
However, corrosion of electrodes from saltwater hampers the mass production of green hydrogen. Therefore, there is a critical need for strong and effective electrocatalyst technology that can avoid or withstand chloride corrosion and precipitate formation on the electrodes. Worldwide, considerable R&D activities are going on to develop coatings for electrodes, to employ semi-permeable membranes, to create novel platinum catalysts to address corrosion or to develop alkaline base electrode to withstand corrosion and enhance efficiency in salt water electrolysis. Similar zeal is missing in the Indian context. As a result, we may have to depend on imported technologies for fulfilling the hydrogen mission.
The writer is a professor at NCAER. View are personal