Gone are the days of rooftop solar. In the near future, we are going to see rooftop hydrogen, if we are to believe what the scientific community and industry experts are saying. Storing solar electricity in batteries has been an expensive proposition, though the sharp fall in battery costs is promising. Since the world is moving swiftly into hydrogen, there is an alternative for the batteries. One could make use of the electricity from the rooftop solar plant to split water right on the roof to produce hydrogen. There are emergent technologies that are making possible photolysis – splitting water directly using sunlight, without the interface of electricity – using photoelectrochemical cells (PEC). Prof Aravind Kumar Chandiran, who heads the Solar Energy Research Group at IIT Madras, has said that they have developed “a new material” that can be used to split water under sunlight. Prof Mohammed Qureshi of IIT Guwahati has said recently that his team developed a catalyst that, when used as a ‘photoanode’, can split water into hydrogen and oxygen. Prof Qureshi feels that it would be too early to comment whether this could be downsized for a rooftop plant, but many others in the academia and industry feel small-sized hydrogen generators will be ubiquitous in the future. Even if you want to keep aside technologies for splitting water directly from sunlight and look only at conventional electrolysis, there is plenty of evidence to indicate that small-scale hydrogen plants are arriving. “Fundamental physics says that these are technologies where size does not matter,” says Arne Ballantine, CEO and co-founder of Ohmium, a US-headquartered company that has started producing electrolysers from Bengaluru. “Yes, the idea of ‘rooftop hydrogen’ becomes very, very real,” Ballantine said, adding, “We are moving past the world of chemical plants where the most efficient way to make hydrogen was with a huge installation.”
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The idea of ‘rooftop hydrogen’ becomes very, very real
