Mukesh Ambani’s call to bring down green hydrogen costs to less than a fifth of present levels has brightened the spotlight on this clean fuel. Speak-ing earlier this month, the Reliance Indus-tries top boss said he sees green hydrogen costs coming down to a dollar per kg in a decade.

       But Ambani’s clarion call will not be enough to reach those levels; a mix of financial and technological interventions will be needed. Much like any other fuel, hydrogen, when burnt, can be used for industrial purposes. But the by-product of burning hydrogen is water, making it the ...