india

Updated: Nov 14, 2019 04:31 IST

As Delhi’s air pollution levels shot through the roof on Wednesday, the second severe pollution spike this month, the Supreme Court asked the Centre to explore two emergency solutions: hydrogen-based fuel for the city’s transport system and setting up giant smog towers to help purify the air in a 10-km radius.

Experts, however, said these are “futuristic” and “emergency” measures and will not holistically address the problem of air pollution from a multitude of sources.

The Supreme Court had asked the Environment Pollution Control Authority (EPCA) last June to look into the use of hydrogen-fuelled buses to reduce air pollution in Delhi.

The EPCA had held consultations with experts, including Indian Oil Corporation Limited (IOCL)’s R&D Centre and Tata Motors, which had deployed the first hydrogen fuel cell. The EPCA in its report no 88 for SC had highlighted that hydrogen cell buses were in a nascent stage, with Tata Motors developing two prototypes for Delhi and Faridabad.

No permits from the ministry of transport, BIS specifications and Petroleum and Explosives Safety Organisation (PESO) regulations exist for hydrogen fuel in India.

The cost of production of hydrogen (as of 2018) using naphtha fuel from the Panipat refinery in India is $ 4-5/kg, but the delivered cost including infrastructure is expected to be around $12/kg, comparable to global costs that range from $14 in US to $12 in Europe, and $8 in Japan.

“Hydrogen is not competitive with conventional fuels (1 kg of hydrogen is equal to roughly 3.8 litres of petrol)”, the report had stressed, pitching for H-CNG instead.

In H-CNG, hydrogen is blended (20-30%) with natural gas and then compressed to dispense into vehicles. US, Brazil, Canada, and South Korea have all conducted trials and found emission reductions.

“We have two projects. The hydrogen fuel cell project is still in an experimental stage. We are still working on cell structure and hydrogen production pathways. We have another project on hydrogen-CNG, which will be used in 50 buses in Delhi soon. We are soon going to commission an H-CNG plant also,” said SSV Ramakumar, director, R&D, IOCL.

“I am not sure about the effectiveness of such purifiers because they have not been tried in Delhi. The first step will be to develop a prototype. It is an emergency measure and I can understand why SC has recommended it. Air pollution is in critical stages in Delhi. But we have to understand it will be a short-term solution. The research on hydrogen-based fuel in India is in very nascent stage and we are not yet in a position to scale it up. We shouldn’t lose time and energy on immediate measures alone,” said Sagnik Dey, associate professor, Centre for Atmospheric Sciences.

“We do not have a prototype as of now but can definitely develop it when needed. The one in Beijing hasn’t been very successful in curbing ambient air pollution but it definitely reduces concentrations. Prototype will depend on what kind of range we are expecting. These towers can run on electrical power as solar isn’t very effective in winter. Depending on the amount of air it sucks in, such towers could cost anywhere between Rs 2 and Rs 5 crore,” said Rakesh Kumar, director, CSIR-National Environmental Engineering Research Institute. “They are effective in a limited area. We have documented some benefits,” said VK Shukla, in-charge of air quality management, Central Pollution Control Board.

NEERI has deployed over 50 Wayu air purifiers for Delhi’s traffic junctions but a study on the effectiveness is yet to be published. These filters work like vacuum cleaners and cause some turbulence to disperse pollutants. They are effective only in a 20-30m radius.

“Every scientist I know has repeatedly pointed out that outdoor air purifiers will achieve very little. There is no alternative to tackling each of the emission sources systematically year round,” said Santosh Harish, fellow at Centre for Policy Research.