Question 63→ 2025 IAS Prelims GS I : Genius Classroom Explanation
📘 IAS Prelims 2025 — GS-III Q.63 | Classroom Explanation
(Ethanol Production | Feedstock Geography | Energy–Environment Interface)
📌 Question Recap
Statement I:
Of the two major ethanol producers in the world, Brazil and the United States of America, the former produces more ethanol than the latter.
Statement II:
Unlike in the United States of America where corn is the principal feedstock for ethanol production, sugarcane is the principal feedstock for ethanol production in Brazil.
✅ Correct Answer: (d)
Statement I is not correct but Statement II is correct
🧑🏫 Core Explanation (Step-by-Step)
🔹 Statement I ❌ Incorrect
- The United States is the world’s largest ethanol producer, not Brazil.
- Recent global production data shows:
- USA: ~16 billion gallons/year
- Brazil: ~8–9 billion gallons/year
- Together, USA + Brazil ≈ 80% of global ethanol output, but the USA clearly leads.
👉 Hence, Statement I is factually incorrect.
🔹 Statement II ✅ Correct
- USA: Ethanol is produced mainly from corn (maize)
- Brazil: Ethanol is produced mainly from sugarcane
👉 This distinction is fundamental, well-established, and frequently tested by UPSC.
🌱 High-Value Enrichment Points (Very Important for Prelims)
🔸 1. Energy Efficiency Difference (Why Sugarcane Matters)
- Sugarcane ethanol (Brazil):
- Much higher energy return on energy invested (EROI)
- Lower lifecycle greenhouse gas emissions
- Corn ethanol (USA):
- Energy-intensive cultivation
- Higher fertilizer, water, and fossil-fuel input
👉 This explains why Brazilian ethanol is considered more climate-efficient, even though total volume is lower.
🔸 2. Environmental Footprint Comparison
| Aspect | USA (Corn Ethanol) | Brazil (Sugarcane Ethanol) |
|---|---|---|
| Feedstock | Corn (food crop) | Sugarcane (energy crop) |
| Water use | High | Moderate |
| GHG reduction | ~20–30% | ~80–90% |
| Co-products | DDGS (animal feed) | Bagasse (bio-power) |
🔸 3. Co-product Advantage in Brazil (Exam Favourite)
- Bagasse (fibrous residue of sugarcane):
- Used to generate bio-electricity
- Makes sugar mills energy self-sufficient
- USA corn ethanol does not have such strong energy co-generation advantage.
🔸 4. India Connection (Prelims Relevance)
- India’s Ethanol Blended Petrol (EBP) Programme:
- Initially grain-based (maize, rice)
- Gradually shifting towards sugarcane-based ethanol
- Brazil is often cited as a model for India’s ethanol economy.
🔸 5. UPSC Trap Alert 🚨
- UPSC often tests:
- “Who produces more?” vs “Who is more efficient?”
- Brazil is more efficient per unit,
but USA produces more in absolute terms.
🎯 Final Answer Recap
- ❌ Statement I — Incorrect
- ✅ Statement II — Correct
✅ Correct Answer: (d)
Statement I is not correct but Statement II is correct