UPSC Prelims 2012 Q12: Environment & Ecology – Renewable Energy & Green Technologies
Biomass gasification is considered to be one of the sustainable solutions to the power crisis
in India. In this context, which of the following statements is/are correct?
1. Coconut shells, groundnut shells and rice husk can be used in biomass gasification.
2. The combustible gases generated from biomass gasification consist of hydrogen and
carbon - dioxide only.
3. The combustible gases generated from biomass gasification can be used for direct heat
generation but not in internal combustion engines.
Select the correct answer using the codes given below :
- (a) 1 only
- (b) 2 and 3 only
- (c) 1 and 3 only
- (d) 1, 2 and 3
Answer: (a) 1 only
Explanation
Biomass gasification
Gasification heats biomass with a limited supply of air, turning it into a burnable gas called producer gas.
| Statement | Verdict | Fact |
|---|---|---|
| 1. Coconut shells, groundnut shells and rice husk can be used in biomass gasification | Correct | Any dry farm residue will do |
| 2. The combustible gases consist of hydrogen and carbon dioxide only | Incorrect | Producer gas has carbon monoxide, hydrogen and methane; carbon dioxide does not burn |
| 3. The combustible gases can be used for direct heat generation but not in internal combustion engines | Incorrect | Producer gas can run engines to generate electricity |
Producer gas, roughly:
| Gas | Burns? |
|---|---|
| Carbon monoxide | Yes |
| Hydrogen | Yes |
| Methane | Yes |
| Carbon dioxide, nitrogen | No |
Uses: village power plants, rice mills, irrigation pumps.
Answer: (a) 1 only.
Why each option is right or wrong
- (a) CORRECT. Only statement 1 is true: shells and husk can be gasified.
- (b) Incorrect. Statements 2 and 3 are both false.
- (c) Incorrect. Statement 3 is false; the gas can run engines.
- (d) Incorrect. Statements 2 and 3 are false.
Key point
Biomass gasification: farm residues burnt in limited air give producer gas (CO, hydrogen, methane); usable for heat and in engines for power.
Remember
Producer gas = CO + hydrogen + methane; runs engines.
Common mistakes
- Accepting 'only' in statement 2.
- Thinking carbon dioxide is a fuel gas.
- Confusing gasification (producer gas) with biogas from digestion.
Exam tip
Carbon dioxide never burns. Any list of fuel gases with only hydrogen and carbon dioxide is wrong.
Sources
- Ministry of New and Renewable Energy — Biomass Gasifier Programme
- The Energy and Resources Institute — Biomass gasification technology