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:

Only statement 1 is correct, so the answer is A. This is a question on producer gas, the product of biomass gasification, in which partial combustion of biomass at high temperature with limited air yields a mixture of combustible and non-combustible gases.

• Statement 1 (correct): Agro-residues such as coconut shells, groundnut shells and rice husk are standard feedstocks for gasifiers in India. Their low bulk density and high carbon content suit this process.
• Statement 2 (wrong): Producer gas is not just hydrogen and carbon dioxide. Its combustible constituents are carbon monoxide, hydrogen and methane, along with non-combustible carbon dioxide and nitrogen. Carbon monoxide is the main combustible component, and it is often left out of such options.
• Statement 3 (wrong): Producer gas is used in internal combustion engines, both dual-fuel and spark-ignition gas engines, for captive and decentralised power generation. It is also used for direct heating, so the 'but not' part of the statement is false.

Mains angle: gasifier-based systems support decentralised power in villages where grid extension is costly, and they use crop residue that would otherwise be burnt. This ties into energy security and rural electrification themes.

Trap: aspirants who recall that producer gas is 'mostly hydrogen' or 'mostly CO2' pick option B or D. Remember CO, H2 and CH4 are the combustible components.