Previous Year Question

Hydrogen (H₂) is important as a Clean Fuel because its complete combustion primarily produces Water (H₂O). Hydrogen contains no carbon; therefore, its combustion does not generate Carbon Dioxide (CO₂), Carbon Monoxide (CO), or Soot from fuel-bound carbon. The reaction between hydrogen and oxygen is represented as 2H₂ + O₂ → 2H₂O + Energy. This characteristic makes hydrogen a fuel that generally produces less pollution at the point of use compared with Diesel, Kerosene, and Coal.

In a Hydrogen Fuel Cell, electrical energy is generated directly through an Electrochemical Reaction between hydrogen and oxygen. This process does not involve combustion, and when pure hydrogen is used, the main by-products are water and heat. Therefore, fuel cells do not directly emit pollutants such as CO₂, Sulfur Dioxide (SO₂), or Particulate Matter during operation. However, burning hydrogen in air at high temperatures can produce Nitrogen Oxides (NOₓ) because atmospheric nitrogen and oxygen may react at elevated temperatures.

Diesel, Kerosene, and Coal are carbon-containing fossil fuels. Their combustion releases CO₂, while CO, NOₓ, SO₂, and fine particles may also be emitted depending on combustion conditions and fuel composition. Diesel engines are important sources of Nitrogen Oxides and soot particles. Kerosene, particularly when used in older or inefficient stoves and lamps, can cause household air pollution. Coal combustion may release Fly Ash, sulfur oxides, and other pollutants in addition to CO₂. These emissions are associated with respiratory diseases, Acid Rain, and Climate Change.

The overall environmental impact of hydrogen also depends on its production method. Producing hydrogen from natural gas through Steam Methane Reforming or from coal can generate substantial CO₂ emissions. In contrast, Green Hydrogen, produced through water Electrolysis using renewable energy sources such as solar or wind power, can have significantly lower life-cycle greenhouse gas emissions. Therefore, hydrogen can be a low-pollution fuel, but it should not be regarded as completely pollution-free under every production and application pathway.