UPSC Prelims 2010 Q63: Environment & Ecology – Renewable Energy & Green Technologies
Given below are the names of four energy crops. Which one of them can be cultivated for
ethanol ?
- (a) Jatropha
- (b) Maize
- (c) Pongamia
- (d) Sunflower
Answer: (b) Maize
Explanation
Which energy crop can be cultivated for ethanol
Among the four listed energy crops, only one is suited to ethanol production rather than bio-diesel.
| Option | Verdict | Reason |
|---|---|---|
| (a) Jatropha | Incorrect | Jatropha is a bio-diesel feedstock (oil-seed crop), not an ethanol source |
| (b) Maize | Correct | Maize (corn) is a classic starch/sugar-rich crop used for ethanol production via fermentation |
| (c) Pongamia | Incorrect | Like Jatropha, Pongamia is an oil-seed crop for bio-diesel, not ethanol |
| (d) Sunflower | Incorrect | Sunflower is primarily an oil-seed crop, used for cooking oil/bio-diesel, not ethanol |
Bio-diesel vs ethanol feedstocks:
| Type | Crops |
|---|---|
| Bio-diesel (oil-seed crops) | Jatropha, Pongamia, Sunflower |
| Ethanol (starch/sugar crops) | Maize, sugarcane, etc. |
Answer: (b) Maize.
Why each option is right or wrong
- (a) Incorrect. Jatropha is an oil-seed crop for bio-diesel, not ethanol.
- (b) CORRECT. Maize, being starch-rich, is fermented to produce ethanol.
- (c) Incorrect. Pongamia is also an oil-seed, bio-diesel crop, not for ethanol.
- (d) Incorrect. Sunflower is primarily an oil-seed crop, not an ethanol source.
Key point
Among Jatropha, Maize, Pongamia, and Sunflower, only MAIZE (a starch-rich crop) is suited to ethanol production via fermentation — the other three are oil-seed crops for bio-diesel.
Remember
Maize: the energy crop among these four suited to ethanol production, unlike the oil-seed bio-diesel crops (Jatropha, Pongamia, Sunflower).
Common mistakes
- Confusing oil-seed crops (bio-diesel feedstocks) with starch/sugar crops (ethanol feedstocks).
- Assuming all 'energy crops' serve the same bio-fuel pathway.
- Not knowing maize's role in ethanol fermentation, distinct from oil extraction.
Exam tip
Oil-seed crops (Jatropha, Pongamia, Sunflower) → bio-diesel. Starch/sugar crops (Maize) → ethanol. Two distinct bio-fuel pathways.
Sources
- Ministry of New and Renewable Energy, Government of India — National Policy on Biofuels (2009)
- Planning Commission, Government of India — Report of the Committee on Development of Bio-Fuel (2003)