IIT Madras study: PEM electrolysers can cut power use in green hydrogen

IIT Madras researchers say proton exchange membrane electrolysers can improve efficiency versus alkaline systems and that design choices can reshape lifecycle emissions and material needs for scale-up

As India moves ahead with its ambitious Green Hydrogen Mission, targeting annual production of 5 million tonnes (mt) by 2030, researchers at the Indian Institute of Technology Madras (IIT Madras) have found that the choice of electrolyser technology will be critical to scaling up green hydrogen production efficiently. The study indicates that Proton-Exchange Membrane (PEM) electrolysers offer higher efficiency than the alkaline systems widely used in the country.

 

PEM electrolysers typically reduce specific electricity consumption by nearly 10-15 per cent compared with conventional alkaline units operating under similar conditions. This corresponds to a relative efficiency improvement of about 8-12 percentage points on a lower heating value (LHV) basis. 

   

“In practical system terms, this often translates to about 5-8 kilowatt-hours less electricity per kilogram of hydrogen produced using PEM systems compared with standard industrial alkaline plants,” said Satyanarayanan Seshadri, head of The Energy Consortium at IIT Madras.

 

Launched in January 2023, the Green Hydrogen Mission also aims to scale up domestic manufacturing of electrolysers — a goal that aligns with the IIT Madras study’s emphasis on more efficient and advanced electrolyser technologies.

 

The key findings of the IIT Madras study indicate that different configurations of PEM electrolysers result in significantly varying environmental impacts. For instance, coating bipolar plates with electrocatalysts increases the lifetime and operational efficiency of the electrolyser. While this raises emissions during manufacturing, the hydrogen produced is significantly cleaner over the system’s lifetime, demonstrating that careful technology selection is critical for sustainable scale-up.

 

“Our research focuses on a type of electrolyser called the PEM system. PEM electrolysers are more efficient than traditional alkaline systems and are well-suited for producing large quantities of hydrogen, making them ideal for India’s plans to scale up clean energy production,” said Peter Waiyaki, a research scholar at IIT Madras.

 

India is committed to achieving net-zero carbon emissions by 2070 and aims to generate 50 per cent of its electricity from non-fossil fuel sources by 2030. Green hydrogen — a clean fuel produced from renewable energy — can play a central role in reducing emissions from hard-to-abate sectors such as industry, transport and buildings.

 

By providing a low-emission and versatile energy carrier, green hydrogen can strengthen energy security, reduce dependence on fossil fuels and support the country’s sustainable development goals.

 

“Our research provides a comprehensive roadmap for expanding green hydrogen production in India. By understanding the environmental and material implications of different technologies, we can make informed choices that ensure both efficiency and sustainability,” Seshadri said. “This study highlights the critical link between technology selection and environmental outcomes, which will be essential for policymakers and industry as India scales up its hydrogen sector.”

 

The study also emphasises the importance of standardising green hydrogen classification. Variations in technology result in hydrogen with differing emission footprints, even when all hydrogen is produced from renewable energy. The research proposes a tiered classification system — platinum, gold, silver and bronze — to clearly communicate the environmental quality of hydrogen to policymakers, investors and industry stakeholders.

 

The study further provides guidance on securing critical raw materials required for PEM electrolysers, helping mitigate supply risks and ensure that India’s green hydrogen infrastructure can grow reliably. The research lays the foundation for future studies, including improved life-cycle data, more detailed assessments of production pathways and robust analyses of material availability.