📚 Topic 466: Energy Resources and Electricity Generation | 专题466：能源资源与发电
Energy can neither be created nor destroyed. It can only be transferred from one store to another. In this revision article, we explore how different energy resources are used to generate electricity, how to describe energy transfers accurately, and how to evaluate the advantages and disadvantages of each resource.
能量既不能凭空产生，也不能凭空消失，只能从一种能量储库转化为另一种能量储库。本文系统梳理如何利用不同能源发电、如何准确描述能量转化，以及如何评价各种能源的优缺点，帮助你在爱德思IGCSE科学考试中掌握关键考点。
1. Renewable and Non-renewable Resources | 可再生与不可再生能源
A renewable energy resource is one that is naturally replenished at a rate equal to, or faster than, the rate at which it is used. Examples include solar, wind, hydroelectric, wave, tidal, geothermal and biomass energy.
可再生能源是指其自然补充速度等于或快于消耗速度的能源。常见例子包括太阳能、风能、水能、波浪能、潮汐能、地热能和生物质能。
A non-renewable energy resource is one that is used faster than it can be replaced over a useful human timescale. Examples include coal, oil, natural gas and nuclear fuels such as uranium.
不可再生能源是指其消耗速度远快于自然补充速度的能源。常见例子包括煤、石油、天然气以及铀等核燃料。
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Non-renewable resources are finite; they will eventually run out.
不可再生资源是有限的，最终会耗尽。
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Renewable resources are usually cleaner, but they may be unreliable or expensive to install.
可再生能源通常更清洁，但可能不稳定或安装成本较高。
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In the exam, you must be able to classify a resource and justify your answer.
考试中，你需要能够对能源进行分类，并说明理由。
2. Fossil Fuels | 化石燃料
Coal, oil and natural gas are fossil fuels. They were formed from the remains of ancient plants and small marine organisms over millions of years. When burned, they release chemical energy as thermal energy.
煤、石油和天然气是化石燃料。它们由古代植物和海洋微生物的遗骸经过数百万年形成。燃烧时，储存的化学能以热能形式释放出来。
In a fossil-fuel power station, the fuel is burned to heat water in a boiler. This produces high-pressure steam, which turns a turbine. The rotating turbine turns a generator, producing electrical energy.
在化石燃料发电站中，燃料燃烧加热锅炉中的水，产生高压蒸汽，蒸汽带动涡轮机旋转，涡轮机再带动发电机转动，从而产生电能。
The main advantage of fossil fuels is reliability. Power stations can generate electricity on demand. However, burning fossil fuels produces carbon dioxide, a greenhouse gas, and sulfur dioxide, which can cause acid rain.
化石燃料的主要优点是稳定可靠，可以按需发电。但燃烧化石燃料会产生温室气体二氧化碳，以及可能导致酸雨的二氧化硫。
3. Nuclear Energy | 核能
Nuclear energy comes from the nucleus of an atom. In nuclear fission, a large and unstable nucleus, such as uranium-235, splits after absorbing a neutron. This releases a very large amount of thermal energy.
核能来自原子核内部。在核裂变中，铀-235等大型不稳定原子核在吸收一个中子后发生分裂，释放出巨大的热能。
The heat from nuclear fission is used to produce steam. The steam turns a turbine and generator in a similar way to a fossil-fuel power station. During operation, nuclear power stations do not release carbon dioxide.
核裂变产生的热量用于产生蒸汽，蒸汽驱动涡轮机和发电机，工作方式和化石燃料发电站类似。核电站在运行过程中不会排放二氧化碳。
Nuclear power is a non-renewable energy resource because uranium is limited. It also produces radioactive waste, which must be stored safely for thousands of years. In the Sun, energy is released by nuclear fusion, where small nuclei join together; this is not yet a practical method of electricity generation on Earth.
核能属于不可再生能源，因为铀资源有限。核电站还会产生放射性废物，必须安全储存数千年。太阳释放能量靠的是核聚变，即小原子核聚合在一起；但核聚变目前在地球上还不是实用的发电方式。
4. Solar Energy | 太阳能
Solar cells, also called photovoltaic cells, convert light energy directly into electrical energy. They can be used in remote locations where there is no mains electricity supply.
太阳能电池，也叫光伏电池，将光能直接转化为电能。它可以用在远离主电网的地区。
Solar thermal panels are different. They use sunlight to heat water, often for household use. Solar energy is renewable and clean, but the amount of electrical energy produced depends on the time of day, the weather and the season.
太阳能集热板与太阳能电池不同，它利用阳光加热水，通常用于家庭生活热水。太阳能是可再生且清洁的，但发电量取决于一天中的时间、天气和季节。
In the exam, be careful to distinguish between solar cells and solar panels. One produces electricity; the other transfers energy to heat water.
在考试中，要注意区分太阳能电池和太阳能集热板。前者用来发电，后者用来加热水。
5. Wind and Hydroelectric Power | 风能与水力发电
Wind turbines use the kinetic energy of moving air to turn blades. The blades rotate a shaft connected to a generator. Wind power is clean and renewable, but it is intermittent because the wind does not blow constantly.
风力发电机利用流动空气的动能推动叶片旋转，叶片带动转轴和发电机。风能清洁可再生，但风不是一直存在的，所以发电不稳定。
Hydroelectric power stations use the gravitational potential energy of water stored in a reservoir. When the water is released, it flows downhill through pipes and turns a turbine connected to a generator.
水力发电站利用水库中水的重力势能。放水时，水沿管道流下，冲击涡轮机旋转，涡轮机带动发电机发电。
Hydroelectric power can respond quickly to changes in electricity demand. However, building a reservoir floods large areas of land and can damage habitats.
水力发电能迅速响应电力需求变化。但建造水库会淹没大片土地，破坏栖息地。
6. Wave and Tidal Energy | 波浪能与潮汐能
Wave energy uses the up-and-down motion of waves to drive a generator. It is renewable and has low running costs, but wave intensity varies and the equipment must survive harsh ocean conditions.
波浪能利用波浪上下运动驱动发电机。它可再生、运行成本低，但波浪强度变化大，设备还要承受恶劣的海上环境。
Tidal energy uses the movement of water caused by tides. A tidal barrage can hold water at high tide and release it through turbines at low tide. Tides are very predictable, which makes tidal energy more reliable than wind or wave energy.
潮汐能利用潮汐引起的水流运动。潮汐坝可以在涨潮时蓄水，退潮时放水冲击涡轮机。潮汐非常规律，因此潮汐能比风能和波浪能更可靠。
In the exam, tidal energy is sometimes confused with wave energy. Remember that tides are caused mainly by the gravitational pull of the Moon, while waves are caused by wind moving over the ocean surface.
考试中，潮汐能常与波浪能混淆。请记住：潮汐主要由月球引力引起，而波浪主要由风吹过海面引起。
7. Geothermal and Biomass Energy | 地热能与生物质能
Geothermal energy comes from heat stored deep inside the Earth. Cold water can be pumped down into hot rocks, and the water returns as steam or hot water. This heat can be used to generate electricity or to warm buildings directly.
地热能来自地球内部储存的热量。冷水被泵入深层高温岩层后，以蒸汽或热水形式返回地面。这些热量可用于发电，也可直接给建筑物供暖。
Geothermal energy is renewable and releases very little carbon dioxide. However, it is only practical in areas where hot rocks are close to the surface.
地热能可再生，二氧化碳排放极少。但只有在高温岩层接近地表的地方才适合开发。
Biomass energy comes from plant or animal material. Biofuels such as bioethanol and biogas can be produced from crops, wood or food waste. Burning biomass releases carbon dioxide, but the plants took in carbon dioxide as they grew, so biomass can be described as approximately carbon neutral if it is produced sustainably.
生物质能来自植物或动物材料。生物乙醇和沼气等生物燃料可由农作物、木材或食物废料制成。燃烧生物质会释放二氧化碳，但植物生长时也吸收了二氧化碳，因此如果以可持续方式生产，生物质能可大致视为碳中和能源。
8. Energy Transfers in Power Stations | 发电站中的能量转化
In most large power stations, the energy resource is used to create high-pressure steam. The steam carries thermal energy and is then used to turn a turbine. The turbine has kinetic energy and turns the generator. The generator transfers kinetic energy into electrical energy in the cables.
在大多数大型发电站中，能源被用来产生高压蒸汽。蒸汽携带热能，然后推动涡轮机旋转。涡轮机具有动能，带动发电机转动，发电机再将动能转化为电能输送到电网中。
For a fossil-fuel or biomass power station, the energy transfer can be written as:
对于化石燃料或生物质发电站，能量转化可以写成：
chemical energy → thermal energy → kinetic energy → electrical energy
化学能 → 热能 → 动能 → 电能
For a nuclear power station, replace chemical energy with nuclear energy. For hydroelectric, wind and tidal power, the first store is kinetic or gravitational potential energy. The final step is always the same: kinetic energy of the turbine is transferred to electrical energy by the generator.
对于核电站，把化学能换成核能即可。对于水力、风力和潮汐发电，初始能量是动能或重力势能。但最后一步都一样：涡轮机的动能通过发电机转化为电能。
9. Efficiency and Sankey Diagrams | 效率与能流图
No energy transfer is perfectly efficient. Energy is usually transferred to wasteful stores, such as thermal energy in the surroundings and sound energy from moving parts.
任何能量转化都不是完全高效的。能量通常会转移到无用的储库中，例如环境中的热能以及机械运动产生的声能。
Efficiency can be calculated using the equation:
效率可以用下列公式计算：
efficiency = useful output energy ÷ total input energy × 100%
效率 = 有用输出能量 ÷ 总输入能量 × 100%
For example, if a bulb receives 100 J of electrical energy each second and produces 10 J of useful light, then its efficiency is (10 ÷ 100) × 100% = 10%.
例如，一盏灯每秒输入100焦耳电能，产生10焦耳有用光能，那么它的效率是（10 ÷ 100）× 100% = 10%。
A Sankey diagram shows energy transfers as arrows. The width of each arrow is drawn proportional to the amount of energy. The input arrow is drawn from the left, the useful output arrow points to the right, and the wasted energy arrow points downwards.
能流图用不同宽度的箭头表示能量转化。箭头的宽度与能量大小成正比。输入箭头从左方进入，有用输出箭头指向右方，浪费的能量箭头指向下方。
10. Environmental Impact | 环境影响
Each energy resource has a different environmental impact. In extended answer questions, you should compare at least one advantage and one disadvantage, and link your comment to the specific resource named in the question.
每种能源对环境的影响都不同。在长答题中，你需要至少比较一个优点和一个缺点，并将观点与题目中提到的具体能源联系起来。
| Resource | 能源 | Carbon
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