Year 9 Science Unit 3 — Energy Block 4: Future Energy SC5-EGY-01 ⏱ ~35 min Lesson 21 of 24

Future Energy and Alternative Sources

By 2050, the world's population will reach nearly 10 billion people, and global energy demand could double. Australia, with its vast renewable resources and export partnerships with Asia, is positioning itself as a clean energy superpower. But the path to net-zero emissions requires technologies that do not yet exist at scale — from hydrogen export hubs to next-generation nuclear reactors. In this lesson, you will explore the emerging energy technologies that could power the second half of this century.

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Think First

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Before you begin, estimate:

By 2050, global electricity demand is projected to roughly double from today's levels. If solar and wind can only supply 60% of that demand reliably, what other energy sources might fill the gap? List three possibilities, then check your predictions against the technologies covered in this lesson.

Core Concepts

Core Concept

Global Energy Trends and Future Needs

The world is in the middle of the largest energy transition in history. Three forces are driving change:

Climate targets: 195 countries signed the Paris Agreement, committing to limit warming to 1.5–2°C. This requires net-zero CO₂ emissions by 2050.
Energy access: 750 million people still lack electricity. Developing nations need affordable, scalable energy.
Technology cost: Solar and battery costs have dropped 90% since 2010, making renewables the cheapest electricity source in most countries.

Data: IEA World Energy Outlook 2023 (simplified projections)

Emerging Technologies

Beyond Wind and Solar

While solar and wind will dominate the next decade, several emerging technologies could become critical for a fully decarbonised grid:

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Green Hydrogen

Hydrogen produced by splitting water using renewable electricity (electrolysis). Burns cleanly to produce only water. Best for: heavy industry, shipping, aviation, and seasonal energy storage. Australia: The Pilbara and Gladstone are earmarked for massive hydrogen export hubs to supply Japan and Korea. The Hydrogen Energy Supply Chain (HESC) pilot in Victoria shipped the world's first liquid hydrogen cargo to Japan in 2022.

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Tidal and Wave Energy

Harnesses the kinetic energy of ocean tides and waves. Tidal barrages trap water at high tide and release it through turbines; wave converters bob on the surface. Predictable unlike wind/solar. Australia: The Australian Maritime College in Tasmania tests wave energy converters. The King Island renewable energy project combines wave, wind and solar with battery storage.

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Geothermal Energy

Uses heat from Earth's interior. Hot rock or steam reservoirs drive turbines. Baseload capable (runs 24/7). Australia: Geodynamics demonstrated Australia's first enhanced geothermal system in the Cooper Basin (SA/QLD), where granite at 4 km depth reaches 240°C. While not yet commercial, the potential is vast — Australia's geothermal resources could theoretically supply the nation's electricity needs 100× over.

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Advanced Nuclear (SMRs)

Small Modular Reactors (SMRs) are factory-built nuclear reactors producing 50–300 MW — much smaller than traditional 1,000 MW plants. They can be deployed remotely and refuelled every 3–7 years. Controversial in Australia due to waste and proliferation concerns, but the CSIRO and Australian Nuclear Science and Technology Organisation (ANSTO) monitor global developments. No nuclear power stations currently operate in Australia.

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Advanced Biofuels and Algae

Next-generation biofuels from algae, agricultural waste, and purpose-grown crops. Algae can produce 10× more oil per hectare than palm oil without competing for farmland. Australia: The Queensland Micro- and Nanotechnology Centre researches algae biofuel production using CO₂ from power stations. Qantas has flown test flights using biofuel blends.

Evaluation

Evaluating Future Energy: An Ethical Framework

SC5-EGY-01 requires you to evaluate energy sources using ethical and sustainability considerations. When assessing any future energy technology, consider these four dimensions:

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Environmental Impact

Lifecycle emissions, land use, water consumption, habitat disruption, waste products.

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Economic Viability

Capital cost, operating cost, levelised cost of energy (LCOE), jobs created, export potential.

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Social Equity

Who benefits? Who bears risks? Indigenous land rights, community consultation, energy access for remote regions.

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Security & Risk

Supply chain vulnerabilities, geopolitical dependence, accident risk, waste management, proliferation concerns.

Key insight: No single energy source scores perfectly on all four dimensions. Solar is clean and cheap but intermittent and land-intensive. Nuclear is low-carbon and reliable but expensive and politically contentious. Hydrogen is versatile but currently energy-inefficient to produce. The "best" energy mix depends on local resources, existing infrastructure, and societal values.

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Australian Context

Australia's Future Energy Advantage

Australia possesses unique advantages for the future energy economy:

Solar resources: The highest average solar irradiance of any continent. The Desert Bloom Hydrogen project plans to use NT sunlight to produce hydrogen for export.
Wind resources: The "Roaring Forties" westerlies provide exceptional wind speeds across southern Australia and Tasmania.
Critical minerals: Australia is the world's largest producer of lithium and a major producer of rare earth elements — essential for batteries, magnets, and electronics.
Geographic position: Proximity to major Asian energy markets (Japan, Korea, China, Singapore) positions Australia as a potential clean energy exporter.
Research capacity: CSIRO, ANU, and UNSW are world leaders in solar cell efficiency, battery chemistry, and hydrogen production research.

ARENA (Australian Renewable Energy Agency) has funded over 600 projects with $2.5 billion in grants, accelerating technologies from laboratory to commercial scale. The Clean Energy Finance Corporation (CEFC) has invested $15 billion in clean energy projects. Together, these agencies are transforming Australia's research leadership into industrial reality.

Think First

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Before you begin, estimate:

Green hydrogen production via electrolysis is currently about 70% efficient — meaning 30% of the electrical energy is lost. If Australia produces hydrogen using solar energy and ships it to Japan, where it is converted back to electricity in a fuel cell (50% efficient), what percentage of the original solar energy ends up as electricity in Japan? Think step by step: solar → hydrogen → transport → electricity.

Quick Questions

1. Which of the following is the main advantage of green hydrogen as an energy carrier?

AIt is more efficient than direct electricity transmission BIt can store and transport renewable energy for use when needed CIt produces no emissions during combustion DIt is cheaper to produce than solar electricity

2. Why is tidal energy considered more predictable than solar or wind energy?

ATides follow the gravitational pull of the moon and sun, which is precisely calculable BTidal energy produces a constant voltage regardless of conditions CTidal turbines are not affected by storms or ocean currents DTidal energy requires no maintenance and lasts forever

3. Australia is positioning itself as a potential "clean energy superpower" primarily because:

AIt has the world's largest coal reserves BIt has built more nuclear power stations than any other country CIts population is small and energy demand is declining DIt has exceptional solar/wind resources and proximity to Asian markets

4. When evaluating future energy technologies, which of the following is NOT one of the four key ethical dimensions?

AEnvironmental impact BEconomic viability CPolitical popularity DSocial equity

5. Geothermal energy in Australia is most promising in regions where:

AThere is high rainfall and many rivers BHot granite exists at accessible depths below the surface CThe coastline is exposed to strong prevailing winds DThere are large deposits of uranium ore

Short Answer Questions

1. Explain why green hydrogen is described as an "energy carrier" rather than an energy source. Describe one advantage and one disadvantage of using hydrogen for energy storage compared to lithium-ion batteries. (3 marks)

💡 Hint: Energy carrier = stores/transports energy made elsewhere (not naturally occurring like coal or sunlight). Advantage: hydrogen stores more energy per kg, good for long-duration/seasonal storage and transport. Disadvantage: lower round-trip efficiency (35% vs 85-95% for batteries), more complex infrastructure.

✏️ Answer in your exercise book.

2. Calculate the overall efficiency of a hydrogen energy chain: solar electricity (100%) → electrolysis (70%) → compression and shipping (90%) → fuel cell (50%). Show your working and explain what happens to the "lost" energy at each stage. (4 marks)

💡 Hint: Multiply efficiencies: 1.0 × 0.70 × 0.90 × 0.50 = 0.315 = 31.5%. Losses: electrolysis → heat; compression → heat/mechanical; fuel cell → heat. Only 31.5% of original solar energy becomes electricity.

✏️ Answer in your exercise book.

3. Evaluate the statement: "Australia should invest only in solar and wind and ignore all other energy technologies." Use the ethical framework from this lesson (environmental, economic, social, security) to construct a balanced argument for and against this position. (5 marks)

💡 Hint: For: solar/wind are cheapest, abundant in Australia, low emissions. Against: intermittency requires storage/backup; hydrogen export potential; geothermal baseload; nuclear for dense grids; diversification reduces risk. No single technology solves everything.

✏️ Answer in your exercise book.

📖 Model Answers

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MCQ Answers

1. B — Green hydrogen stores and transports renewable energy for use when needed.

2. A — Tides are predictable because they follow gravitational forces.

3. D — Australia's renewable resources and Asian market proximity create export potential.

4. C — Political popularity is not one of the four scientific evaluation dimensions.

5. B — Geothermal requires hot rock at accessible depths (e.g., Cooper Basin).

SAQ 1 — Hydrogen as Energy Carrier (3 marks)

Marking Criteria: 1 mark — explains why hydrogen is a carrier (not naturally occurring, must be manufactured using energy from another source). 1 mark — one valid advantage over batteries. 1 mark — one valid disadvantage over batteries.

Model answer: Green hydrogen is called an energy carrier rather than an energy source because hydrogen gas (H₂) does not exist in usable quantities in nature. It must be manufactured — typically by using electricity to split water into hydrogen and oxygen (electrolysis). The energy stored in hydrogen originally came from another source, such as solar or wind. This makes hydrogen a carrier, like a battery or a tank of petrol, rather than a primary source like sunlight or coal.

One advantage of hydrogen over lithium-ion batteries is energy density by mass. Hydrogen contains about 33 kWh per kg, while lithium-ion batteries store about 0.25 kWh per kg. This makes hydrogen far better for applications where weight matters, such as aviation and long-distance shipping. Hydrogen can also be stored indefinitely and transported through pipelines or as liquid, making it suitable for seasonal energy storage.

One disadvantage is round-trip efficiency. The full chain — electrolysis (70%), transport (90%), fuel cell (50%) — results in only about 31.5% of the original electrical energy being recovered. Lithium-ion batteries achieve 85–95% round-trip efficiency. This means hydrogen wastes more than twice as much energy as batteries for the same storage task, making it less efficient for short-term cycling.

SAQ 2 — Hydrogen Chain Efficiency (4 marks)

Marking Criteria: 1 mark — multiplies efficiencies correctly. 1 mark — states final percentage (31.5%). 1 mark — identifies at least two stages where energy is lost. 1 mark — explains the form of lost energy (heat, mechanical).

Model answer: To find the overall efficiency, multiply the efficiency of each stage:

Overall efficiency = 100% × 70% × 90% × 50%
= 1.0 × 0.70 × 0.90 × 0.50
= 0.315 = 31.5%

Only 31.5% of the original solar energy ends up as electricity after the complete hydrogen chain.

The "lost" energy becomes heat at each stage:

• Electrolysis: About 30% of electrical energy becomes heat rather than chemical energy in hydrogen bonds. The electrolyser and surrounding water warm up.

• Compression and shipping: Compressing hydrogen gas requires mechanical work, and some energy is lost as heat in compressors and during cooling to cryogenic temperatures (-253°C) for liquid transport.

• Fuel cell: The chemical reaction converting hydrogen and oxygen back to water is only 50% efficient in converting chemical energy to electricity. The remaining 50% is released as heat warming the fuel cell stack.

SAQ 3 — Evaluating "Solar and Wind Only" (5 marks)

Marking Criteria: 1 mark — presents a clear evaluation stance. 1 mark — uses environmental dimension with evidence. 1 mark — uses economic dimension with evidence. 1 mark — uses social/security dimension with evidence. 1 mark — balanced conclusion acknowledging complexity.

Model answer: The statement "Australia should invest only in solar and wind and ignore all other energy technologies" is an oversimplification that ignores the complexity of energy system design. While solar and wind are essential, a diversified portfolio is necessary for reliability, economic resilience, and global competitiveness.

Environmental: Solar and wind produce near-zero emissions during operation and are environmentally superior to fossil fuels. However, both are intermittent — they do not produce electricity on demand. Relying solely on them would require massive overbuilding or storage, which has its own environmental footprint (lithium mining, land use for pumped hydro reservoirs).

Economic: Solar and wind are now the cheapest sources of new electricity in Australia. However, ignoring hydrogen export would forfeit a potential $100 billion+ industry supplying clean fuel to Japan and Korea. Ignoring geothermal would leave Australia's vast hot-rock resource untapped. Economic diversification reduces exposure to any single technology's cost fluctuations.

Social/Security: A solar-and-wind-only grid could face supply security risks during extended wind lulls or cloudy weeks. The 2021 Texas blackout demonstrated how over-reliance on one source type creates vulnerability. Furthermore, remote mining communities and Indigenous settlements may benefit from small modular nuclear or geothermal where renewable + battery combinations are impractical.

In conclusion, solar and wind should dominate Australia's energy future, but diversification into hydrogen, storage, and potentially geothermal or nuclear creates a more resilient, export-capable, and reliable energy system. The ethical framework demands we evaluate all options rather than committing to a single technology.

Game: Doodle Jump

🔄 Revisit These Concepts

L17: Circuit Basics L18: Series & Parallel L19: Ohm's Law L20: Checkpoint 3

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Australian Fun Fact

The World's Largest Battery Is in Victoria

The Victorian Big Battery near Geelong, completed in 2021, was the largest lithium-ion battery in the southern hemisphere at the time — 450 MW / 450 MWh. It uses Tesla Megapacks and charges during the day using surplus solar power, then discharges during evening peak demand. In its first year of operation, it saved Victorian electricity consumers an estimated $50 million by reducing the need for expensive gas peaker plants. The battery can power over 500,000 homes for one hour — or equivalently, provide grid-stabilising frequency response in milliseconds.

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Sports Science

Solar-Powered Cricket Venues

The Melbourne Cricket Ground (MCG) — the world's 10th largest stadium — installed a 1,000-panel solar array on its roof in 2018, generating enough electricity to power the stadium's lighting and operations on sunny match days. During the Boxing Day Test, when 90,000 fans attend, the MCG consumes up to 5 MW of power for lighting, broadcasting, catering, and refrigeration. The solar system reduces grid demand by approximately 10% during daytime events. The MCG also uses a battery system to store excess solar energy for evening matches, demonstrating how large entertainment venues can integrate renewable generation, storage, and grid connectivity — the same principles you have studied in this unit.

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