Primary General Studies: Renewable Energy (Paper 2 (intermediate))

2026-11-13

Tutor Prep Guide · Renewable energy sources, how they generate power and capacity sums

Paper two compares renewable sources and introduces capacity factor, efficiency and the cube law for wind, with percentage work and decimals.

Direct answers　For questions about how many times larger, write the proportional or cube relation first, then take the power, then scale the original value.

01　Paper details (check answers afterwards)

Item	Detail
Questions	10
Suggested time	20
Difficulty mix	Foundation 3 · Intermediate 3 · Challenge 3 · Error redo 1
Chapter	Chapter: Primary General Studies: Renewable Energy
Level	parts of a closed circuit, conductors against insulators, series against parallel, adding up battery voltage, and electrical safety

02　Questions (10 items)

FoundationWhich of these is non-renewable: solar, wind or coal?
FoundationWhich kind of energy does a hydroelectric plant mainly use?
FoundationWhat is biomass energy mainly obtained from?
IntermediateIf wind speed rises from 5 m/s to 10 m/s, by what factor does the available wind power change?
IntermediateA small hydro plant passes 3 600 m³ of water an hour and each cubic metre yields 0.2 kWh. What is the hourly output?
IntermediateA city uses 45 000 GWh a year and 0.5 per cent of it is renewable. How many GWh is that?
ChallengeSunlight is 1 000 W/m² and a panel is 18 per cent efficient. What power does 1 m² give?
ChallengeA 2.5 kW solar system gets 5 effective sun hours a day. What does it produce in 30 days?
ChallengeA wind farm has six 2 MW turbines with a 30 per cent capacity factor. What does it generate in a year of 8 760 hours?
Error redoA classmate says solar panels work at night, so storage is unnecessary. What is wrong?

03　Answers and one-line notes

#	Answer	One-line note
1	Coal.	Coal is a fossil fuel with limited reserves, while solar and wind are continually replaced by nature.
2	The potential energy released as water flows from a high level to a low level.	A reservoir stores water high up, and the falling water drives turbines so potential energy becomes electrical energy.
3	Biological material such as plants, crop residues and organic waste.	Burning or breaking down biomass gives heat and electricity, and because plants absorb carbon dioxide as they grow the carbon footprint is lower than fossil fuels.
4	About 8 times.	Wind power varies with the cube of wind speed, and 2 cubed is 8.
5	720 kWh.	3 600 times 0.2 is 720 kWh, and a larger flow gives more electricity.
6	225 GWh.	45 000 times 0.005 is 225 GWh, so the renewable share is still small.
7	180 W.	1 000 times 0.18 is 180 W, and a higher efficiency means more power from the same panel.
8	375 kWh in total.	2.5 times 5 times 30 is 375 kWh.
9	About 31.5 GWh.	Capacity is 6 times 2, that is 12 MW, and 12 times 0.3 times 8 760 is 31 536 MWh, about 31.5 GWh.
10	Panels only generate when there is sunlight, so nights and cloudy days need storage or another source.	Supply and demand do not always coincide, and batteries or pumped storage keep daytime electricity for the night.

04　What to do after marking

After marking, redo only the wrong items and write down which step went wrong (formula, unit, or misread number).
Repeat the same item two days later; move to the next paper only when both attempts are correct.
Parents only need the answer and note columns; there is no need to explain every item.

Then try paper three, using voltage and current to work out power and resistance.Tutor Registration →

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