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:
1. The main advantage of the use of H-CNG is the elimination of carbon monoxide emissions.
2. H-CNG as fuel reduces carbon dioxide and hydrocarbon emissions.
3. Hydrogen up to one-fifth by volume can be blended with CNG as fuel for buses.
4. H-CNG makes the fuel less expensive than CNG.
Which of the statements given above is/are correct?
Explanation
Statement 1 is incorrect: Utilizing H-CNG significantly reduces carbon monoxide (CO) emissions (by up to 70%), but it does not completely eliminate carbon monoxide emissions.
Statement 2 is correct: The addition of hydrogen promotes more complete combustion at higher flame speeds, which measurably decreases emissions of carbon dioxide (CO2) and unburnt hydrocarbons (HC).
Statement 3 is correct: Standard pilot trials and technological guidelines recommend blending hydrogen up to 18% to 20% by volume (up to one-fifth) with compressed natural gas without requiring major engine re-engineering.
Statement 4 is incorrect: Hydrogen production, high-pressure blending, and specialized storage logistics make H-CNG more expensive to produce than conventional CNG.
Therefore, statements 2 and 3 are correct — Option B.