Final Questions — All-Book

All chapters together · Total: 70 marks

A. Fill in the blanks (8 × 1 = 8 marks)

1. Annual energy = capacity × 8,760 × factor.
2. The maximum efficiency of a single-junction solar cell is about %.
3. Grid frequency in India is held near Hz.
4. Energy out divided by energy in for a store is the efficiency.
5. In hydrogen direct reduction of iron, the by-product is .
6. About % of cement’s CO₂ comes from limestone decomposing.
7. Fusion energy out divided by heating energy in is called .
8. Lifetime cost divided by lifetime units generated is called .

B. True or False (8 × 1 = 8 marks)

1. A 1 MW solar plant and a 1 MW nuclear plant generate the same annual energy. ( ___ )
2. Tandem solar cells can exceed the single-junction limit. ( ___ )
3. Batteries are the cheapest way to store energy for several months. ( ___ )
4. Electric drivetrains are more efficient than petrol engines. ( ___ )
5. Clean electricity alone can decarbonise cement. ( ___ )
6. A fusion power plant currently supplies electricity in India. ( ___ )
7. A lower capacity factor raises the levelised cost per unit. ( ___ )
8. Indian Railways has electrified almost all of its broad-gauge network. ( ___ )

C. Choose the correct option (8 × 1 = 8 marks)

1. A 2 MW turbine generating 5,256 MWh a year has a capacity factor of (a) 20% (b) 30% (c) 50%
2. Grid inertia comes mainly from (a) spinning generators (b) solar inverters (c) transmission lines
3. India’s grid batteries mostly use (a) LFP (b) NMC (c) lead-acid
4. An EV using 0.15 kWh/km over 100 km at ₹8/unit costs (a) ₹120 (b) ₹700 (c) ₹1,200
5. Green hydrogen costs are dominated by (a) electricity price (b) water cost (c) pipeline length
6. The D–T fusion reaction releases about (a) 1.6 MeV (b) 17.6 MeV (c) 176 MeV
7. Most of the cost of a solar plant’s electricity is (a) fuel (b) capital (c) staff
8. A just transition is mainly about (a) workers and communities (b) panel efficiency (c) grid frequency

D. Match the columns (6 × 1 = 6 marks)

E. Short answers with working (7 × 2 = 14 marks)

1. A 150 MW wind farm generates 394 GWh a year. Find its capacity factor.
2. Explain why grid frequency falls when demand exceeds supply, and what operators do about it.
3. Why can a tandem cell beat 33%, when silicon alone cannot?
4. A 50 MWh battery charges with 55 MWh. State its round-trip efficiency and where the rest went.
5. Compare the yearly CO₂ of a petrol car and an EV driven 15,000 km, stating your assumptions.
6. Write the two iron-reduction reactions and explain why one is climate-friendly.
7. What would it take for fusion to move from Q > 1 to a working power plant?

F. Long answers — any TWO (2 × 13 = 26 marks)

1. You advise a state government with a 40 GW evening peak. Design a 2035 electricity mix. Justify each choice with capacity factors, storage duration and cost, and state the trade-offs you accept.
2. Write a reasoned essay: “India should electrify transport before it cleans up industry.” Argue one side, then answer the strongest objection.
3. A coal district of 3 lakh people faces the closure of its mines over fifteen years. Write a just-transition plan with timelines, jobs, retraining and finance.
4. Compare fusion, small modular reactors and grid batteries as answers to the evening-peak problem, in terms of timeline, cost and risk.