Year 9 Science · Unit 3 · Lesson 21
Challenge Worksheet
Learning Goals
1. (a) Describe how grey, blue and green hydrogen are each made. (b) Give two reasons why no fusion power station is making electricity yet.
Investigation: two rooftop solar panels
In full sunlight, 1,000 W of light falls on each square metre. A class models two possible panels, each with an area of 1.7 m², in full sunlight. Panel B is a hypothetical future tandem panel.
| Panel | Light power falling on it (W) | Electrical power out (W) |
|---|---|---|
| A: silicon | 374 | |
| B: perovskite–silicon tandem | 527 |
Source: illustrative model values, not measured panel results. Panel A is representative of commercial silicon modules; Panel B is hypothetical, informed by research-cell efficiencies above 30% (Fraunhofer ISE). Cell results do not establish the same efficiency for a rooftop-size module.
2. (a) Complete Table 1, then find each panel’s efficiency. (b) A roof has space for 12 panels. On a day equal to 5 hours of full sunlight, how much electrical energy would 12 panels of each type produce?
(a) Panel A %
(a) Panel B %
(b) 12 of A kWh
(b) 12 of B kWh
3. A news story says: “Perovskite panels are 40% better than silicon, so a house will need 40% fewer panels.” Use Table 1 to test both parts of the claim, and show the number of B panels that would match the output of 12 A panels.
B panels
Find the mistake: shipping sunshine to Japan
A student worked out how much of 1,000 MWh of Pilbara solar electricity would reach a factory in Japan as electricity. The hydrogen is shipped as ammonia.
| Stage | Efficiency |
|---|---|
| Electrolyser makes hydrogen | 65% |
| Hydrogen made into ammonia and shipped | 80% |
| Ammonia turned back into hydrogen | 85% |
| Fuel cell makes electricity | 55% |
Student’s working: “Energy lost = 35% + 20% + 15% + 45% = 115%. More than 100% of the energy is lost, so this chain cannot work and no electricity reaches Japan.”
4. Explain the student’s mistake. Then calculate the efficiency of the whole chain, to one decimal place, and the electricity that reaches the factory.
Overall efficiency %
Delivered MWh
What if…? Fusion goes commercial
Imagine it is 2060. The ITER project and several private companies have succeeded, and fusion power stations are being built around the world. They make electricity from deuterium, which can be extracted from seawater, with no CO₂ emissions and no long-lived radioactive waste, and their cost is falling. Australia is one of the world’s largest exporters of coal and liquefied natural gas (LNG).
5. Predict what commercial fusion would mean for Australia’s coal and gas exports. Decide whether solar and wind farms built in the 2020s would still have been worth building. Then give one ethical argument for, and one against, waiting for fusion instead of switching to renewables now.