Chapter 9 — Energy Resources

Energy is the ability to do work or to cause change. We use energy to cook food, light our homes, move from place to place and run machines. Energy is part of many daily activities: when you walk, eat, study with a lamp, or play a radio. There are many sources of energy and they can be natural or made by people.

People get energy in different forms: heat, light, motion and electricity. Heat energy warms our houses and cooks food. Light energy helps us see. Motion energy moves vehicles and machines. Electricity is a very useful form that can be changed into light, heat or motion.

Energy resources are important because they make life comfortable and support industry, farming and transport. But not all resources are the same. Some can be used again and again without running out in our lifetimes; these are called renewable. Others take millions of years to form and can be used up; these are called non-renewable. How we use energy affects the environment. Burning some fuels makes smoke and pollution, which can harm plants, animals and people.

As students you will learn to recognise the energy around you and to think about using it carefully. Simple habits like switching off lights when not needed or walking instead of using a vehicle can save energy. Understanding energy helps in making good choices that protect nature and save money.

Energy resources are grouped by how quickly they are replaced in nature and how long they last. Non-renewable resources

Renewable resources

Both groups have advantages and limits. Non-renewable fuels often give a lot of energy in a small amount and are easy to transport and use. But they pollute the air, contribute to climate change and will finish someday. Renewable sources are usually cleaner and more sustainable, but many depend on weather (sun and wind) or require space and equipment such as dams, solar panels or wind turbines. They may need storage solutions because sunlight and wind are not always constant.

Think about the things around you: the petrol used in a school bus is from oil, a wood stove uses biomass, and a hydroelectric dam uses river water. Different places choose different energy mixes: a coastal village may use wind and fishers’ diesel engines; a sunny region may favour solar panels. Local availability, cost and technology decide which resources are practical.

Students can carry out simple activities: list the energy sources used at home, sort them into renewable and non-renewable, and discuss why each is used. Classroom charts and local maps help show which resources are nearby. Understanding the difference helps children make wise choices like planting trees, saving fuel and supporting clean energy projects that protect the environment for future generations.

Coal is a dark, combustible rock used as a fuel and energy source. It began as plants growing in ancient swamps and forests millions of years ago. When these plants died, their remains collected in waterlogged places where they were partly protected from decay. Layers of mud and sand covered the plant material. Over very long periods, heat and pressure from the earth transformed these layers into peat and finally into different kinds of coal. This slow change is called coalification.

There are several types of coal which differ by how much the plant matter has changed and how much carbon they contain. Peat is partly changed plant material and is lowest in energy. Lignite, often called brown coal, contains more carbon. Bituminous coal is darker and a common fuel for power plants and industry. Anthracite is the hardest and richest in carbon and gives more heat when burned.

Coal has many uses. The largest use is to produce heat in power stations to make electricity. In factories it is used to produce steam and high temperatures needed for industrial processes such as making steel and cement. Coke, a product made by heating coal in the absence of air, is used in iron and steel production. In some rural areas, coal is still burned in small furnaces for heating and cooking.

Burning coal releases energy but also produces smoke and gases such as carbon dioxide and sulphur dioxide which cause air pollution, health problems and acid rain. Coal mining changes the landscape and can harm plants and animals; underground mining may cause subsidence. To reduce harm, modern power stations use filters and scrubbers, and people look for cleaner energy or ways to use coal more efficiently. Students should learn both the usefulness and the environmental costs of coal so they understand why conserving energy and seeking cleaner options is important.

Petroleum, commonly called crude oil, is a thick liquid found under the ground and under the sea bed. It started long ago from tiny sea plants and animals that died and sank to the sea floor. Buried under layers of sand and mud, their remains were changed by pressure and heat over millions of years into oil and natural gas trapped in rock pockets. People find oil by drilling wells into these rock layers.

Crude oil itself is not a single product. At an oil refinery, crude oil is heated and separated into many useful materials by a process called fractional distillation. Lighter parts become petrol (gasoline) used in cars and scooters. Heavier parts become diesel for trucks and buses, kerosene for lamps and cooking in some areas, and lubricating oils for machines. Other parts are raw materials for making plastics, paints, medicines and many chemical products.

Oil is very important for modern life because it powers transport, factories and agriculture. It is easy to move in liquid form and to use in engines. But oil has problems: burning petrol and diesel produces smoke and gases that pollute the air and add to global warming. Oil spills in the sea damage fish, birds and coastal communities. Because crude oil is a non-renewable resource, its supply may become limited in the future and prices can rise when demand is high.

To protect the environment, people work to reduce oil use by promoting public transport, fuel-efficient vehicles, and alternatives like electric vehicles and biofuels. At the household level, fixing leaks, avoiding unnecessary idling of vehicles, and safe storage of oil products help reduce risk. Students should know how petrol and diesel reach daily life and why careful use and handling of oil matter. Learning about oil helps children understand choices about travel, waste and protecting water bodies from spills.

Natural gas is a gas formed under the earth, usually in the same places where oil is found. It is mostly methane and is lighter than air in its pure form. Natural gas is taken from underground by drilling wells and is often transported through long pipelines to homes, industries and power plants. It can also be compressed and stored in tanks for vehicles as CNG (compressed natural gas).

Natural gas burns more cleanly than coal and oil. When burned it produces a lot of heat but much less smoke and fewer impurities. For this reason it is a preferred fuel for cooking in many cities, and it is used to heat water, for industrial heating processes and to generate electricity in power stations. Gas-based power plants can be started and stopped easily to meet changing electricity needs, which helps balance the electricity grid.

Although natural gas is cleaner than other fossil fuels, it is still non-renewable and adds carbon dioxide to the air when burned. Methane, the main component, is itself a potent greenhouse gas if released into the atmosphere without burning. Leaks in pipelines or storage can be dangerous because natural gas is flammable. Therefore, safety, regular maintenance and careful handling are essential. In cities, gas supply is often controlled through metered pipelines with safety valves and trained technicians to prevent accidents.

For students, practical ideas include learning to turn off the gas stove after use, recognising the smell added to gas for safety, and understanding that CNG vehicles produce less smoke than petrol or diesel vehicles. Communities use natural gas because it gives good energy and lower pollution, but long-term planning must include finding renewable clean alternatives and preventing leaks to protect people and the climate.

Biomass is organic matter from plants and animals used as fuel. It includes wood, crop residues like straw and husk, animal dung and specially grown energy plants. Biomass stores the Sun's energy because plants use sunlight to grow. People have used biomass for cooking and heating since ancient times. In rural areas it remains a key source of fuel for many families.

Modern methods turn biomass into cleaner forms of energy. When organic waste or dung is placed in an airtight tank called a biogas digester, bacteria break it down and produce biogas, a mixture containing methane. Biogas can be piped to a kitchen as a clean cooking fuel and the leftover material (slurry) can be used as good fertilizer. Other ways include making briquettes from agricultural waste, producing biofuels like ethanol from crops, and using improved cookstoves that burn biomass more completely with less smoke.

Biomass is renewable if plants are regrown and waste is managed carefully. However, cutting too many trees for fuel causes deforestation, soil erosion and loss of wildlife habitat. Open burning of crop residue or dung produces smoke that can harm health, especially for women and children who cook indoors. Improved technologies such as smokeless stoves, efficient biogas plants and sustainable planting reduce these problems. Local choices matter: planting fast-growing trees, using farm waste for briquettes, and recycling kitchen waste into compost or biogas both provide energy and protect soil and water.

Students can learn simple actions: collect dry leaves for composting, support tree planting at school and home, and understand how a biogas plant works. Small household and community steps add up, making biomass a useful part of a cleaner, renewable energy mix when managed well.

Solar energy comes from the Sun and reaches the Earth as light and heat every day. It is a vast and renewable source of energy that people can use directly for many purposes. Because sunlight is available in most places, solar energy is especially useful in regions with clear skies and long sunny days. It is clean and does not produce smoke or gases when used.

There are several ways to use solar energy. Solar water heaters use dark surfaces and pipes to absorb sunlight and warm water for bathing and washing. Solar cookers concentrate sunlight to cook food without fuel, which is useful for outdoor cooking and demonstration projects. Solar panels, or photovoltaic (PV) cells, convert sunlight directly into electricity; the electricity can run lights, fans and small appliances. Many homes and schools install small solar panels to charge batteries for use at night. Solar lanterns and streetlights are popular in places with weak or no grid electricity.

Solar devices require correct placement and care. Panels should face the Sun and be kept clean for best performance. Solar electricity depends on sunshine, so batteries or other storage methods are needed to give power at night. Initial cost can be higher than some other options, but solar devices save money over time because sunlight is free. For students, simple experiments show how dark coloured objects heat faster in the sun and how solar panels produce a small voltage in sunlight. Learning about solar energy helps children appreciate a clean power source and think about using sunlight in everyday life, such as drying clothes, heating water, or powering study lamps when there is no electricity.

Wind energy uses the movement of air to produce power. When wind blows, it pushes on the blades of a windmill or a modern wind turbine causing them to turn. The rotating blades turn a shaft connected to a generator that makes electricity. Wind farms are groups of turbines often placed on coasts, hilltops or open plains where wind speeds are higher and more reliable.

Wind energy is renewable and produces no air pollution during operation. Large wind farms can produce electricity for many homes, while small wind machines provide power to single villages, farms or schools. Besides electricity, windmills have traditionally been used to pump water for irrigation and to grind grain. Modern wind turbines are designed to be efficient at different wind speeds and include systems to turn the blades out of strong winds to avoid damage.

There are important considerations when using wind energy. Wind does not blow the same everywhere or all the time; a site must be surveyed for good wind speed before installing turbines. Building wind turbines needs roads, strong foundations and maintenance. Turbines may cause noise and their tall structures change the visual landscape; some bird species can be affected if turbines are not placed carefully. Despite these issues, wind energy has low running costs and can be combined with solar power and batteries to give a more stable electricity supply. For students, making simple pinwheels helps to understand how blade size and shape affect rotation and power. Learning about wind energy shows how natural movement of air can be transformed into useful, clean electricity for communities.

Hydropower uses the energy of moving or falling water to make electricity. When water flows in a river or falls from a height, it has energy that can turn a wheel or turbine. In a typical hydropower system, a dam may be built to store water in a reservoir. Water released from the reservoir flows through pipes called penstocks and strikes turbine blades, causing them to spin. The turbine is connected to a generator which converts the motion into electricity.

Hydropower is renewable because rain and melting snow refill rivers and lakes. It can produce large amounts of electricity and is often used to supply whole regions or cities. One advantage is that the amount of electricity can be changed quickly by opening or closing water gates, so hydropower helps balance the electricity grid when demand rises or falls. Small hydropower projects use the natural drop of a stream without large dams and can provide local power with less environmental change.

However, building large dams can have serious effects. Reservoirs may flood forests and farmland, displacing people and wildlife. Fish migration and river ecosystems can be altered, and downstream water supplies can change. Siltation in reservoirs reduces their life and can affect soil fertility downstream. Therefore, planning and environmental study are important before building large dams. Students should learn the main parts of a hydropower plant — reservoir, dam, penstock, turbine and generator — and understand that smaller-scale hydropower and good planning can give many benefits with lower harm. Classroom models using flowing water to turn a small wheel connected to a bulb help make the concept clear and show how water energy becomes electrical energy.

Nuclear energy is produced by changing the structure of atoms to release large amounts of heat. In many nuclear power plants the process used is called fission, where a heavy atom such as uranium is split into smaller parts. When the nucleus of an atom breaks, it releases energy as heat. That heat is used to boil water and make steam. The steam turns turbines that drive generators, just as in other thermal power stations, to produce electricity.

Nuclear power plants can produce very large amounts of electricity from a small quantity of fuel. They do not burn fossil fuels, so they do not produce smoke or many of the gases that cause air pollution while operating. Because of this, nuclear energy has been used in some countries to reduce the amount of carbon dioxide emitted by electricity generation.

There are important safety and environmental concerns with nuclear energy. The radioactive materials used and produced in the process are dangerous to people and the environment if not managed properly. Nuclear waste remains hazardous for a very long time and must be stored safely. A serious accident can release radiation over a wide area, harming people, plants and animals. For these reasons, nuclear power plants are built with many safety systems, strict rules and trained staff. Building and running a nuclear plant is costly and requires long-term planning for waste disposal and decommissioning. Students should understand the basic idea — heat from atom splitting makes steam to turn turbines — and recognise why strong safety measures and careful long-term planning are necessary when using nuclear energy.

Electricity is produced in many different ways but the basic idea is similar: some form of energy makes a machine turn, and that turning motion drives a generator to produce electric current. In thermal power stations (coal, oil, gas and nuclear), fuel heat produces steam to spin turbines. Hydropower uses falling water to turn turbines directly. Wind turbines use moving air and solar panels produce electricity directly from sunlight without moving parts. Each method converts natural energy into electrical energy that is easy to send and use.

Once electricity is produced, it must travel from the power plant to homes, schools and factories. This is done through a network of wires and stations called the electricity grid. Generators produce electricity at a certain voltage that is increased (stepped up) by transformers for safe long-distance transmission. High-voltage electricity travels through transmission lines with less loss. Near towns, transformers step the voltage down to a safe level before electricity enters houses through distribution lines.

The grid must keep a careful balance between how much electricity is being generated and how much people are using at any moment. If too little power is produced, lights and machines can fail; if too much is produced without demand, equipment can be damaged. Renewable sources like wind and solar change with weather and sunlight, so grids use a mix of power sources, energy storage (batteries) and flexible plants that can quickly increase or decrease output. Simple classroom demonstrations such as a hand-crank dynamo lighting a bulb can show how turning motion creates electricity. Students should also learn safety rules: never touch broken wires, keep water away from electrical fittings and never attempt repairs on mains equipment. Understanding generation and the grid helps students see how many different energy sources work together to give the lights and power we use every day.

Using energy affects the environment in many ways. Burning fossil fuels such as coal, oil and gas releases gases and particles into the air. Carbon dioxide is a greenhouse gas that traps heat in the atmosphere and contributes to global warming. Sulphur dioxide and other pollutants cause smog and can lead to acid rain that harms crops, buildings and water bodies. Smoke from open fires and inefficient stoves causes health problems such as coughing and eye irritation, especially for people who cook indoors.

Other energy activities also change land and water. Mining for coal and drilling for oil can damage habitats, remove topsoil and change landscapes. Oil spills at sea harm fish, birds and coastal communities. Building large dams for hydropower floods areas of land and may displace people and wildlife, while changing river flow patterns and fish migration. Wind turbines and solar farms need land and can change the visual landscape; poorly placed turbines may harm birds. Even renewable projects must be planned carefully to reduce local harm.

There are ways to reduce environmental effects. Cleaner technologies and filters reduce smoke and harmful emissions from plants. Using renewable energy more often reduces greenhouse gas emissions. Energy conservation, recycling and planting trees help protect soil, water and air. Policies such as careful environmental studies before building big projects, better waste management, and protection of forests and wetlands are important. Students can help locally by avoiding open burning of waste, using efficient stoves, conserving electricity at home and supporting tree planting. Understanding these links between energy use and environment helps young learners see why choices about energy have consequences beyond today and why thinking about clean and careful use matters for the future.

Energy conservation means using less energy to do the same job and avoiding waste. It is an important habit that saves money, reduces demand on power stations and lowers pollution. Many small actions by families, schools and communities add up to large savings. For children, learning simple routines now helps build a lifetime habit of careful energy use.

There are easy and effective ways to save energy at home and at school. Turning off lights and fans when leaving a room, closing doors and windows when the air-conditioner or fan is on, and using natural daylight during the day reduce electricity use. Replacing old bulbs with energy-saving bulbs or LEDs uses much less power for the same light. In the kitchen, covering cooking pots with lids, using pressure cookers to shorten cooking time, and preparing several dishes together save fuel. Maintaining appliances so they work efficiently — for example keeping a refrigerator clean and not leaving its door open — also reduces energy waste.

Transport choices can save fuel: walking or cycling for short trips, using school buses or carpooling, and avoiding unnecessary rides. At school, planting trees around buildings provides shade and reduces cooling needs, while using fans instead of air-conditioning when possible saves energy. Recycling waste and composting organic material reduces the need to burn or transport waste. Communities can support energy-saving by choosing efficient street lighting and encouraging public transport.

Students can make simple plans: check that lights are off before leaving the classroom, make posters to remind others, and measure electricity use by noting when devices are on or off. These small efforts show how individuals can help preserve resources and protect the environment while saving money for their families. Energy conservation is a practical and powerful part of caring for the planet.