Future Energy and Sustainable Development
AdvancedFossil fuels are finite and emit greenhouse gases; future energy relies on renewables such as solar and wind, backed by storage, hydrogen and smart grids, while Hong Kong pledges carbon neutrality before 2050. Judging energy options means weighing safety, cost and environment together, and saving energy at home is a contribution everyone can make.
- Fossil fuels are finite and emit greenhouse gases; energy decisions balance security, affordability and sustainability.
- Solar, wind and hydro generate with almost no emissions but face intermittency.
- Storage, hydrogen, smart grids and fusion research complete the future-energy puzzle.
文體小知識：能源科技說明文比較各種能源的發電原理、優點和限制，幫助讀者評估未來能源的選擇。
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1Modern life runs on energy: power, transport, manufacturing and cooking all depend on it. Yet the world still leans on fossil fuels, whose underground reserves are finite and whose burning releases great amounts of carbon dioxide. Energy decisions face a 'trilemma': secure supply, affordable price and a sustainable environment. Over the coming decades the world must balance all three and transform step by step.
2Renewable energy is the main trend. Solar panels use the photovoltaic effect in semiconductors to turn sunlight directly into electricity; wind turbines use moving blades to drive generators; hydro power uses flowing water to spin turbines; geothermal and biomass energy join the list. Their shared merits: almost no greenhouse gas while generating, and no exhaustion. Their limit is intermittency — no power at night or in still air — so batteries or backup are needed. Short of land, Hong Kong is installing floating solar systems on reservoirs and studying offshore wind.
3Nuclear and new technologies are options too. Nuclear plants split atoms to make heat for electricity: low emissions, but with debates over waste and safety. Hydrogen burns into water only and can be stored and shipped — the hope for hard-to-decarbonise sectors. Storage batteries keep surplus solar and wind power for later, and smart grids balance supply and demand with data. Scientists are also studying nuclear fusion, mimicking the Sun; once achieved, fuel would be almost endless.
4Sustainable development means meeting today's needs without damaging the ability of future generations to meet theirs. UN Sustainable Development Goal 7 is affordable clean energy, Goal 13 climate action, and Hong Kong pledges carbon neutrality before 2050. Home energy saving is within everyone's reach: replacing incandescent bulbs with LEDs saves over eighty per cent, choosing Grade 1 energy-label appliances, setting air-conditioning at 25–26°C, and switching off standby power. Critical thinking: no energy source is flawless — citizens should debate trade-offs from data, not feeling alone.
1Summary 重點摘要
Fossil fuels are finite and emit greenhouse gases; future energy relies on renewables such as solar and wind, backed by storage, hydrogen and smart grids, while Hong Kong pledges carbon neutrality before 2050. Judging energy options means weighing safety, cost and environment together, and saving energy at home is a contribution everyone can make.
2Vocabulary cards Vocabulary
Energy such as solar, wind and hydro that does not run out with use.
Technology turning sunlight directly into electricity through the photovoltaic effect.
Electricity made when wind turns blades that drive a generator.
Power from splitting atoms for heat; low emission but waste must be handled.
Energy from burning hydrogen or fuel cells, producing only water.
Keeping surplus electricity in batteries for use when needed.
A modern power network balancing supply and demand with sensors and data.
The trait of solar and wind power depending on weather and time, unable to generate steadily all day.
Balancing emitted greenhouse gases with absorbed or offset amounts to zero.
The grading label showing an appliance's energy efficiency; Grade 1 saves most.
3Step by step Steps
- Step 1: Know the energy trilemmaEnergy choices must balance steady supply, fair price and environmental protection at once, and no source is perfect in all three — hence the energy trilemma. Example: coal is cheap and steady but pollutes; solar is clean but silent at night and costly to install; judge energy on supply, price and environment together. When comparing two energy sources in an exam, draw a table, list the merits and drawbacks under steady supply, price and environment item by item, then conclude which is better overall — the answer then stays organised.
- Step 2: Understand solar powerSunlight can be turned directly into electricity without any exhaust, making solar one of the easiest renewables to use in cities. Example: sunlight excites electrons in a panel's semiconductor and current flows; a south-facing tilted panel peaks in strong summer sun. Output changes with the weather, so solar usually has to work alongside other sources. Hong Kong is promoting solar power too: panels are common on village-house and school roofs, and under the power companies' feed-in tariff scheme households can sell the electricity they generate back to the grid.
- Step 3: Understand wind and hydroWind and hydro both turn movement into electricity; the principle is simple and the equipment lasts long. Example: wind spins three blades that drive the generator in the nacelle; a dam releases water to spin turbines — kinetic energy turning into electricity in both. Neither burns fuel nor emits greenhouse gases, but both need the right site to pay off. Exams may ask about siting: wind turbines need open, steadily windy areas or the sea, while dams need rivers with ample flow and a big drop; with little land, Hong Kong is relatively suited to offshore wind.
- Step 4: Analyse renewables' limitsRenewables depend on the weather and the seasons, so their supply is not steady — a limit that must be faced honestly. Example: after a typhoon, days of cloud cut solar output sharply, so storage batteries discharge to fill in, or backup units take over. Understanding intermittency explains why storage technology matters so much. Picture a storage battery as a giant battery for the whole city: it charges when generation is high and discharges when low; a common mistake is to think solar power can be switched on at will — in reality storage must be solved first.
- Step 5: Learn hydrogen and smart gridsHydrogen and smart grids are two new technologies for taming uneven supply. Example: demand is lowest late at night, so the grid can use surplus wind to split water into hydrogen, and fuel cells turn it back to power by day; a smart meter shows hourly use, helping utilities schedule and users save. Technology makes energy use far more flexible. Note that hydrogen made by electrolysis with renewable electricity is called green hydrogen: using it yields only water and no carbon dioxide, which is why it is seen as a promising clean fuel.
- Step 6: Read Hong Kong's energy goalsHong Kong plans carbon neutrality before 2050 — emissions balanced by what is absorbed. Example: the path includes more renewables, switching to cleaner natural gas and promoting electric cars; the yearly fuel mix statistics can be tracked to check progress. Policy goals need data to monitor them, or they remain slogans. The blueprint also sets an interim target: cut total greenhouse gas emissions by half against the 2005 level before 2035; interim milestones make the long-term goal easier to check and achieve.
- Step 7: Save energy at homeSaving energy is the most direct low-carbon action, open to everyone, and it cuts bills too. Example: swapping five 50-watt bulbs for five 8-watt LEDs lit five hours daily saves about 360 units a year; with a Grade 1 air-conditioner the bill drops clearly. Small changes add up to a remarkable effect. Here is one more comparison: an incandescent bulb lasts about a thousand hours while an LED can run for about twenty-five thousand, saving power, sparing replacements and cutting the waste of discarded bulbs.
4Diagrams Diagrams
5Worked example Example
Example: the student union wants solar panels on the school roof, but some argue 'no sun means no power — not worth installing'. List two benefits and two limits, and answer the doubt.
- Benefit one: solar generates without greenhouse gases, cutting part of the school's power emissions each year, in step with the 2050 carbon-neutrality goal.
- Benefit two: daytime power goes straight to the school, and output peaks in summer when air-conditioning use peaks — saving money, repaying the cost over years.
- Limit one: intermittency — cloudy, rainy days and nights cut output sharply, and the grid is still needed.
- Limit two: cost and maintenance — installation is expensive, and panels must be checked and cleaned after typhoons.
- Answering the doubt: solar need not power the school all day to be worth it; school days' daytime is exactly when use and output both peak, so even partial daytime supply cuts carbon and costs — and the data can become science teaching material.
- Answer: Benefits: no greenhouse gases and savings in the high-use daytime; limits: intermittency, cost and upkeep. Reply: full-day supply is unnecessary — daytime supply already brings real carbon and money savings, plus teaching value.
6Common mistakes Mistakes
7Quick check Quick check
Q1Name two renewable energies and how they generate power.
Q2What is the main limit of renewable energy?
Q3What is carbon neutrality?
Q4Give two ways to save energy at home.
Q5Why must energy choices weigh the 'trilemma'?
8Recap Recap
- Fossil fuels are finite and emit greenhouse gases; energy decisions balance security, affordability and sustainability.
- Solar, wind and hydro generate with almost no emissions but face intermittency.
- Storage, hydrogen, smart grids and fusion research complete the future-energy puzzle.
- Hong Kong pledges carbon neutrality before 2050; UN Goals 7 and 13 point to clean energy and climate action.
- Home saving is for everyone: LED bulbs, Grade 1 labels, 25–26°C air-conditioning, standby off.