Year 10 Science · Unit 4 · Lesson 6
Challenge Worksheet
Learning Goals
Read the graph
Study the bar chart comparing the levelised cost of energy (LCOE) for new electricity sources in Australia. LCOE is the average cost per unit of electricity (per MWh) over a plant's whole lifetime. Lower is cheaper. Answer the questions below using the data shown.
Indicative LCOE of New Electricity Sources, Australia
Indicative figures based on the trends in CSIRO GenCost reporting. Exact values vary year to year; use the relative comparison.
(a) Using the graph, rank the five options from cheapest to most expensive. Which is the single cheapest source of new electricity?
(b) Adding several hours of storage roughly doubles the cost of solar or wind (from about $50-60 to about $100/MWh). Even so, solar/wind plus storage is still cheaper than new nuclear. What does this tell you about the most cost-effective way to build a reliable low-carbon grid?
(c) The cost of utility solar has fallen by over 90% since 2010. Explain why this economic shift, on its own, has done more to drive the renewable transition than environmental policy alone. Refer to the idea of LCOE.
Evaluate the claim
Someone claims...
"Nuclear power is the obvious answer to climate change. It is low-carbon, it runs 24/7 unlike unreliable solar and wind, and Australia has the world's biggest uranium reserves. We should cancel the renewable rollout and build nuclear plants instead, that is the fastest path to net zero by 2050."
(a) Identify the parts of this claim that are factually correct. (At least two.)
(b) Explain why the claim that nuclear is "the fastest path to net zero" is misleading. Use the construction-time argument and at least one other limitation of nuclear.
(c) Write a balanced one-paragraph judgement: should Australia rely mainly on nuclear, mainly on renewables plus storage, or a mix? Justify your position using cost, time and reliability evidence from this lesson.
Wrap Up
In one sentence, what was the main idea of this lesson?
Teacher use, Read the graph
(a) Cheapest to most expensive: utility solar ($50) < onshore wind ($60) < solar/wind + storage ($100) < new gas ($120) < new nuclear ($220). The single cheapest new source is utility-scale solar.
(b) Even with storage added, solar/wind ($100) is far cheaper than nuclear ($220) and cheaper than new gas ($120). So the most cost-effective reliable low-carbon grid is built mainly from solar and wind backed by storage (batteries and pumped hydro), rather than from high-cost nuclear. Reward students who note storage is the integration cost, not a flaw in the generation itself.
(c) Because LCOE is the lifetime cost per unit of electricity, once solar's LCOE fell below that of new coal and gas, building solar became the cheapest choice for new generation on purely financial grounds. Companies and grids then choose it to save money, so the transition is driven by economics, not only by environmental policy or subsidies.
Teacher use, Evaluate the claim
(a) Correct parts (any two): nuclear has near-zero operational emissions (low-carbon); it provides reliable, dispatchable 24/7 power regardless of weather; Australia does hold the world's largest uranium reserves (about 28% of global reserves).
(b) Why "fastest path" is misleading: new nuclear plants take about 10-20 years to build, so a plant announced now would not generate before about 2040-2045, too slow for urgent 2020s-2030s emissions cuts, whereas a utility solar farm can be operating in 12-18 months. Plus at least one other limitation: very high capital cost (most expensive option on the graph); long-lived radioactive waste needing safe storage; large cooling-water use; Australia has no commercial nuclear experience and a federal moratorium; and nuclear is not renewable. Cancelling the renewable rollout would also remove the cheapest, fastest-to-deploy option.
(c) Balanced judgement (model answer): Australia should build mainly renewables plus storage, because solar and wind are the cheapest new sources and can be deployed within 1-2 years, addressing the urgent need to cut emissions this decade; storage (batteries and pumped hydro such as Snowy 2.0) handles intermittency at a cost still below nuclear. Nuclear could play a limited longer-term role for firm baseload, but its 10-20 year build time, very high LCOE and waste issues make it unsuitable as the primary near-term strategy. Award full marks for a clear position justified with cost, time and reliability evidence; accept a well-argued "mix" answer.