Q. In the context of proposals to the use of hydrogen-enriched CNG (H-CNG) as fuel for buses in public transport, consider the following statements : - The main advantage of the use of H-CNG is the elimination of carbon monoxide emissions.
- H-CNG as fuel reduces carbon dioxide and hydrocarbon emissions.
- Hydrogen up to one-fifth by volume can be blended with CNG as fuel for buses.
- H-CNG makes the fuel less expensive than CNG.
Which of the statements given above is/are correct? (UPSC Prelims 2019)
Answer:
2 and 3 only
Notes: The correct answer is
[B] 2 and 3 only. Hydrogen-enriched CNG (H-CNG) is a blend of hydrogen and compressed natural gas, typically used to enhance the combustion properties of conventional CNG.
- Statement 1 (Incorrect): While H-CNG significantly reduces carbon monoxide (CO) emissions (by about 70%), it does not eliminate them entirely. Complete elimination of CO is chemically improbable in internal combustion engines.
- Statement 2 (Correct): The addition of hydrogen improves the fuel-to-air ratio and combustion efficiency, which leads to a reduction in carbon dioxide (CO2) and unburnt hydrocarbon emissions compared to traditional CNG.
- Statement 3 (Correct): In various pilot projects, including those by Indian Oil Corporation Limited (IOCL), hydrogen is typically blended up to 18% to 20% (approximately one-fifth) by volume with CNG for use in public transport buses without requiring major engine modifications.
- Statement 4 (Incorrect): H-CNG is currently more expensive than conventional CNG. The costs associated with hydrogen production, compression, and the blending process make it a pricier alternative at this stage of technological adoption.
- H-CNG is viewed as a "bridge" technology toward a pure hydrogen economy, offering better fuel efficiency and lower emissions than standard fossil fuels.