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Rajya Sabha TV In Depth – HCNG: Fuel of the Future

Rajya Sabha TV In Depth – HCNG: Fuel of the Future

(Topic covered: General Studies III – Science and Technology, Environmental Pollution)

Rising levels of pollution have been a major cause of concern in the National Capital Delhi, which has been put in the list of 20 most polluted cities of the world by World Health Organization. The rise in air pollution is already causing harm to health of its residents. Taking action as per recent orders of the Supreme Court of India to check it, Delhi Government is planning to push Hydrogen-enriched CNG buses on its roads.


CNG bus in Delhi

  • Compressed Natural Gas (CNG) is methane (CH4) stored at high pressure. CNG as a fuel can be used in place of gasoline, diesel fuel and propane (C3H8) / LPG and its combustion produces fewer undesirable gases then the other mentioned fuels. Combustion is a high temperature exothermic chemical reaction between a fuel and an oxidant that produces oxidized products.
  • HCNG is a mixture of compressed natural gas (CNG) and some % Hydrogen by energy.

       HCNG = CNG + H2.

  • HCNG which may be used as a fuel of Internal Combustion Engine (ICE) is considered a cleaner source of fuel, more powerful and offers more mileage then even CNG.
  • Trials of HNCG have been held in countries like US, Brazil and South Korea.
  • Delhi Government has tied up with Indian Oil Corporation Limited to study the technology and infrastructure needs to induct 50 HCNG buses on a trial basis. IOCL has plans to mix (18-20) % Hydrogen in these buses.
  • The shift to HCNG buses in future will be the second big step in Delhi for public transport buses towards a cleaner fuel after the shift to CNG buses in 2002.
  • Delhi Government was earlier planning to shift towards electric buses to curb pollution. But, following the Supreme Court’s order to explore new cleaner fuels, it has made plans to run HCNG buses.
  • There has been a constant stress on reducing the Carbon footprints and stopping the effects of climate change. This has forced the research towards alternative fuels.


Advantages of HCNG:

  • HCNG reduces emissions of CO up to 70%.
  • Enables up to 5 % savings in fuel.
  • First step towards future Hydrogen economy.
  • Engines can be calibrated to release lower amounts of NO.
  • Engines need minimum modification to run on HCNG.
  • Ideal fuel for high load applications and heavy-duty vehicles.
  • Better performance due to higher Octane rating of H2.


Disadvantages of using HCNG:

  • Determining the most optimized H2/ NG (Natural Gas) ratio.
  • It requires new infrastructures for preparing HCNG.
  • Many steps need to be taken for commercializing it at a large scale.
  • Current cost of H2 is more than the cost of Natural Gas. So, HCNG’s cost is more than CNG.


  • Crude oil is a non-renewable source of energy and causes pollution. So, alternative and cleaner fuels like HCNG, CNG, LPG, Alcohol fuels, electricity and biofuels are being explored. Electricity can be generated by sources like nuclear energy, wind power, solar energy, etc as cleaner options.


Due to issues like climate change and estimations that non-renewable fuels like crude oil will get exhausted in near future, exploring new fuels like HCNG is a welcome step. Thus the Government shall now take steps so that alternative fuels can be commercialized by putting required efforts.