UPSC CSE Prelims
Clean Energy Previous Year Questions (PYQs)
Practice solved questions for Clean Energy with detailed step-by-step solutions, key insights, and trend analysis for UPSC CSE PRELIMS.
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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?
Detailed Explanation:
Answer: Option 2 — 2 and 3 only
H-CNG (Hydrogen-enriched Compressed Natural Gas) is a blend of hydrogen and CNG that improves combustion efficiency and reduces emissions. While it significantly reduces carbon monoxide, carbon dioxide, and hydrocarbon emissions, it does not completely eliminate CO emissions since the blend still contains CNG. Additionally, hydrogen production and blending infrastructure make H-CNG more expensive than conventional CNG.
❌ Statement 1 – Incorrect: H-CNG significantly reduces but does not eliminate carbon monoxide emissions entirely, as the blend still contains CNG which produces some CO during combustion.
✅ Statement 2 – Correct: H-CNG reduces carbon dioxide and hydrocarbon emissions compared to conventional CNG due to improved combustion efficiency from hydrogen addition.
✅ Statement 3 – Correct: According to Indian government guidelines, hydrogen can be blended up to 18% by volume with CNG (approximately one-fifth), making this statement correct.
❌ Statement 4 – Incorrect: H-CNG is more expensive than CNG due to the costs associated with hydrogen production, storage infrastructure, and blending technology.
📝 Short Notes: Hydrogen-Enriched CNG (H-CNG)
- Composition: H-CNG is a blend of hydrogen (up to 18% by volume) with Compressed Natural Gas (CNG).
- Emission Benefits: Reduces CO, CO₂, HC, NOₓ and particulate matter emissions; improves air quality in urban areas.
- Combustion Efficiency: Hydrogen's high flame speed and wide flammability range improve combustion efficiency and reduce fuel consumption.
- Pilot Projects in India: H-CNG buses have been tested in Delhi as part of government initiatives to reduce vehicular pollution.
- Cost Factor: More expensive than CNG due to hydrogen production (electrolysis or steam methane reforming), storage, and distribution infrastructure requirements.
- Environmental Impact: Not zero-emission fuel (unlike pure hydrogen) but serves as a transitional cleaner alternative to conventional CNG.
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