India to bring back reactors for green hydrogen

By resurrecting a long-forgotten technology that can help with hydrogen production, we can achieve net-zero emissions by the year 2070.

Now that hydrogen’s importance in India’s (or any country) climate action has been recognized, the focus has shifted to finding low-cost means to create the gas.

In this case, a long-forgotten nuclear technology can be quite beneficial. Indeed, India’s obligations at the last COP26 summit — that half of its energy consumption come from non-fossil fuels — cannot be accomplished without nuclear power, as noted by Anil Kakodkar, a well-known nuclear physicist and former chairman of the Atomic Energy Commission.

According to Kakodkar, many additional nuclear plants will be required to raise capacity from 15,000 MW now to 22,480 MW by 2031 if India is to attain “net-zero” emissions by 2070. But that’s an other story.

The more urgent goal is to manufacture green hydrogen for a dollar per kilogram within ten years. For this to happen with current technologies, solar energy prices would have to plummet, which is implausible. For the ‘$1/kg’ aim, you’ll require 55 kWhr of electricity; given the cost of electrolysers and maintenance, electricity should be available for no more than $2 per kWhr.

If you heat the water, you can reduce your electricity consumption, according to Kakodkar. When you heat water to a high temperature, it takes less energy to split it into hydrogen and oxygen. Heating water now necessitates the use of energy. However, ‘high-temperature reactors,’ which the Bhabha Atomic Research Centre experimented with decades ago, may provide this heat at a low cost.

According to Kakodkar, prices might be reduced by heating water with HTRs and then splitting the water into hydrogen and oxygen in an electrolyser.

What exactly is the HTR? A suitable explanation can be found in a presentation given by BARC scientists IV Dulera and RK Sinha during an international symposium on non-electric nuclear power applications held in Oarai, Japan, from April 16-19, 2007. (Sinha later rose to the position of Chairman of the Atomic Commission.) The presentation focused on hydrogen and desalination in particular.

It mentioned an Indian HTR development program that included two components: a 100 kW (thermal), 1,000°C portable ‘compact high-temperature reactor’ (CHTR) for technology demonstration, and a 600 MW (thermal), 1,000°C ‘Indian high-temperature reactor-hydrogen,’ or IHTR-H. The fuel for these two reactors would be TRISO-coated particle fuel. TRISO, or ‘tristructural isotropic,’ is made up of uranium, carbon, and oxygen, all of which India is capable of producing.

The IHTR-H is capable of producing 7,000 kg of hydrogen per hour, 18 MWhr (thermal) of energy per hour, and 9 million litres of water per day.

It’s evident from the presentation that this isn’t just a theory. Both the CHTR and the IHTR-H reactors have detailed designs. These reactors can operate for many years without human intervention.

“Nuclear energy-assisted hydrogen production is expected to play a significant role in the future Indian energy scenario; development of technologies related to high-temperature nuclear reactors is an important step in that direction,” Dulera and Sinha say in the presentation, adding that R&D for the majority of the work has already begun.

BARC has clearly considered hydrogen production since 2007, when hydrogen was not the buzzword it is now.

What happened to the show, though? “It has not been shelved; it is on,” a senior Department of Energy official told Business Line, but declined to elaborate. IHTRs, according to Kakodkar, are the way forward for low-cost green hydrogen production.

Meanwhile, another development in the nuclear sector has the potential to assist India in achieving its net-zero goal: small modular reactors, or SMRs, which might be installed in the spaces left vacant by decommissioned coal-fired power plants.

India has a long history with compact reactors, having operated 220 MW reactors that are not available for export. An 83 MW pressurised light water reactor powers India’s nuclear submarine, INS Arihant.

The SMRs that have gotten the world’s attention, on the other hand, are not designed like traditional small-scale reactors. Over 70 SMR designs are being developed in 18 nations, according to the International Atomic Energy Agency.

According to Kakodkar, India might have a small-scale reactor program running alongside the large-scale projects.