- In the sea tiny plants sink, and a layer of dead plants build up on the seabed. The sea plants are buried in the mud.
- On land too, mud covers dead plants and trees. Slowly the mud hardens into rock. More layers of rock from above and press down on the plants, burying them deeper and heating them up.
- The pressure and heat slowly change the sea plants into oil and then into gas. Land plants turn first to coal before turning into oil and gas. A layer of rock now traps the gas in a deep deposit. Earth movements may have raised the rocks containing the gas above sea level, so that the gas now lies under the land.
- Gas flows up the well to the production platform, and a pipeline takes it to a terminal on land. Gas from inland wells flows straight to the terminal.
- Raw gas has to be cleaned and dried before it could be used. The gas terminal removes impurities and water.
- Gas flows from terminals to large tanks, where it may be frozen and stored as a liquid. The gas can also be stored in huge underground caverns. Pumps push gas along pipes to the place where it is needed.
Useful Gases
Gas wells produce several different sorts of gas. Methane is the main component, but other fuel gases, called propane and butane, also come from gas deposits. The gas terminal stores these gases in metal cylinders for use in house that the gas pipe does not reach. Gas deposits are also a source of helium. Helium is used to fill balloons because it is very light and does not burn. Air is another source of useful gases. Carbon dioxide, the gas that makes the bubbles in fizzy drinks, comes from air. Air also contains a little neon gas. Some advertising signs are glass tubes filled with neon. The gas glows when electricity passes through it.
OIL
Without oil, modern life would grind to a halt. Oil is needed to make the fuel that drives cars, lorries, diesel trains, ships, and aircraft. Power stations burn oil to produce much of the world’s electricity, and many homes use oil-burning boilers for heating. Oil is also very important because it’s needed to make plastics, textiles, and other useful products. Oil is a dark, thick liquid, which lies deep underground and beneath the seabed. Oil wells are bored to obtain oil, which is also called crude oil or petroleum. Crude oil contains a mixture of chemicals and many different types of oil. Lubricating oil is made from crude oil. It helps machine parts slide easily so that the machine works well.
Where oil is found
Oil is found in many places, from the Middle East to the Arctic. But all these places were once covered by the sea. Tiny sea plants sank to the seabed and were buried in mud. The mud turned into layers of rock. Heat from the rocks warmed the plants over millions of years and changed them into oil and natural gas. The crude oil that comes from a deposit is a mixture of chemicals and many kinds of oil. Crude oil is taken to an oil refinery, where it is heated. This makes the oil break down, or separate, into petrol and other fuels, lubricating oils, chemicals, and bitumen for making roads. Some things you might find near an oil refinery are:
- Several wells are drilled to an oil deposit
- Pipeline
- Oil well
- Nodding donkey
- Oil terminal and refinery
- Hugh oil tankers carry oil from offshore platforms to refineries on land
- Divers check and repair platform from below
- Oil workers are ferried to production platform by helicopter
- Some gas from the oil is burned off as a safety precaution
- Oil workers live in quarters on the platform
- A platform may stand on legs and be as tall as a skyscraper. Some platforms do not have legs but rest on huge floats called pontoons
- PIPELINE
Along pipe carries oil from the platform to an oil terminal or tanker port. From there the oil is sent to a refinery
Rigs drill wells down to oil deposits, and oil production platforms bring the oil to the surface. The platforms either float on the sea or stand on the seabed.
Petrol is one of the most important of all oil products. Diesel fuel is another kind of motor fuel made from oil.
Chemicals from oil
An oil refinery produces many chemicals from crude oil, which are called petrochemicals. Factories use these chemicals to make plastics, textiles and other products. Polythene, for example, is made from a gas that comes from oil. Chemicals from oil are also used to make drugs, fertilisers, detergents and dyes and paints in all colours. Plants and vegetables such as olives, peanuts, sunflower and corn, provide valuable oils. Crushing ripe olives makes olive oil; sunflower oils come from sunflower seeds. These oils are used in cooking, and sunflower oil is used to make margarine. Factories treat plant and vegetable oils to make other products, such as soap and paints.
ENGINES
When prehistoric people discovered fire, they found a way of obtaining energy, because burning release heat and light. About one million years later the steam engine was invented, and for the first time people could harness that energy and turn it into movement. Today there are many different kinds of engines, which drive the world’s transport and industry. All engines serve one function-too use the energy stored in a fuel such as oil or coal and change it into motion to drive machines. Before engines were invented, tasks such as building and lifting depended on the strength of people and their animals. Today engines can produce enough power to lift the heaviest weights and drive the largest machines. The most powerful engine is the rocket engine; it can blast a spacecraft away from the pull of the Earth’s gravity and out into space.
Internal Combustion Engine
The engine that powers almost all the world’s cars is the internal-combustion engine. It uses the power of gases created by exploding fuel to produce movement. A mixture of air and tiny droplets of petrol enters the engine’s cylinders, each of which contains a piston. An electrical spark ignites (sets alight) the fuel mixture, producing gases which thrust each piston down.
Diesel Engine
Many trains and lorries have powerful diesel engines that burn diesel fuel instead of petrol. The engine works in the same way as a petrol-fuel engine, but does not have spark plugs. Instead, each cylinder has an injector that squirts diesel fuel into the cylinder. The piston compresses the air, making it very hot. The hot air makes the diesel fuel explode.
Four-stroke engine
Most car engines are four-stroke engines, which means that each piston makes a set of four movements. These are things you might fin on a four- stroke engine:
- Piston 4 rises and pushes waste gases out through exhaust valve.
- Piston 3: mixture explodes, and expanding gases push piston down.
- Piston 2 rises and compresses (squeezes) fuel-air mixture.
- Piston 1 moves down and suck fuel-air mixture in through inlet valve.
- Valves open and close to admit and expel the fuel-air mixture.
- Spark plug produces electrical spark that ignites fuel-air mixture.
- The piston moves up and down inside the cylinder.
- Engines have between four and eight cylinders. These work in sequences to produce continuous movement.
- Crankshaft changes the up-and-down movement of the pistons into circular movement, which drives the wheel.
Electric Motors
Petrol and diesel engines produce waste gases that pollute the air and contribute to the greenhouse effect (which causes the Earth’s temperature to rise). Electric motors are clean quite and produce no pollution. Several car manufacturers are developing cars powered by electric motors. Most electric cars are still experimental; one remaining problem is that sufficiently light, efficient batteries have not yet been developed.
Jet Engine
The jet, or gas turbine, engine now powers most high-speed aircraft. The engine blasts a jet of hot, fast-moving air backward out of its exhaust; this pushes the engine forward. Fan at the front of the engine spin and suck air into the engine and squeeze it at high pressure into several combustion chambers. There, flames of burning kerosene heat the air, which expands and rushes towards the exhaust. As the air streams out, it spins the turbine, which drives the fan at the front of the engine. Some things you may find in a jet engine are:
- Some of the air that enters the engine flows through the bypass duct.
- Large fan spins, sucking air into the engine.
- Compressors-fast-spinning fans- increases the pressure of the air and pushes it into the combustion chambers.
- Hot air and exhaust gases rush out of the engine, spinning the turbine as they go.
- Burning kerosene fuel inside the combustion chambers heats the air and makes it expands violently.
Frank Whittle
In 1928, English pilot and engineer Frank Whittle (1907-) suggested the idea of the jet engine. Whittle’s engine powered an experimental aircraft for the first time in 1941. However, the first jet-powered flight was made during the 1930s in Germany, where engineer Hans Von Ohain had developed his own engine.
Steam Engine
The steam engine was developed during the 18th century and greatly changed people’s lives. It led to the development of industry and transport. People left the land to work in the new factories which contained steam powered machines, and steam railways allowed people to travel further and faster than ever before. Some things you may find in a steam engine:
- Boiler burns wood or coal, producing heat.
- Hot air and smoke pass through pipes that run through the water tank. The heat turns the water into steam.
- Steam and smoke escape through a valve and pour out smokestack.
- The movement of the piston drives the wheels of the train.
- Hot air and smoke pass through pipes that run through the water tank. The heat turns the water into steam.
James Watt
The first engine was a simple steam engine invented by the Greek scientist Hero in the 1st century A.D., but it was little more than a toy. In 1712, the British engineer Thomas Newcomen built the first real engine. It was a huge steam engine used to pump water out of mines. In 1769, another British engineer, James Watt, greatly improved the steam engine. The unit of power, the watt, is named after him.
NUCLEAR ENERGY
The atoms that make up everything in the universe are the source of a huge amount of energy called nuclear energy. Nuclear energy produces the searing heat and light of the sun, the deadly explosions of nuclear weapons, and vast amounts of electricity in nuclear power station. Nuclear energy is based on the fact that matter and energy are different forms of the same thing, and one can be converted into the other. In a nuclear reaction, a tiny amount of matter changes into an enormous amount of energy. The nuclear reaction occurs in the nuclei (centres) of atoms. This can happen in two ways: when the nucleus of a heavy atom splits, in a process called fission, and when two light weight nuclei joined together, in a process called fusion. In nuclear weapons, fission, or fusion occurs in a split second. By contrast, nuclear power stations produce electricity from fission reactions that work at a controlled rate. These are some things you might see:
- Reactor core contains pallets of uranium oxide fuel held in fuel rods. Two thimble-sized pallets would produce enough electricity for a person for one year.
- Pump for high-pressure water system.
- The high-pressure water flows through pipes in a steam generator, which transfers its heat to a separate water system. The water in this second system boils to form steam.
- Water is pumped around the reactor core at high pressure in a sealed circuit. The nuclear reactions heat the water to more than 330 C (500 F) but the high pressure keeps it from turning into steam.
- A third water circuit acts as a coolant, changing the steam back into water, which returns to the steam generator once again.
- Pressurised water reactor (PWR).
- Steam spins turbines that drive generators, producing electricity.
- Metal control rods absorb neutrons and slow down the nuclear reaction, in an emergency, the control rods drop into the reactor core and shut off the nuclear reaction.
- If neutrons travel too rapidly, they bounce off uranium atoms without producing fission. The fuel is surrounded by water, which shows the neutrons down so they produce fission. A material that slows neutrons in a reactor is called a moderator.
Nuclear Fusion
Scientists are trying to build reactors that use nuclear fusion, a process that produces less dangerous waste than nuclear fission. Nuclear fission occurs when hydrogen atoms smash together and join to form heavier atoms of helium. However, nuclear fission is extremely difficult to achieve. Hydrogen atoms must be squeezed by a magnetic field and held at a temperature higher than that in the sun’s centre for fusion to occur.
Nuclear Fission
Nuclear power stations produce energy from the fission of atoms of uranium metal. The impact of a particle called a neutron makes an atom of uranium split. This releases heat energy and two or three neutrons. The neutrons strike other uranium atoms and make them divide. Soon many atoms begin to split, producing a huge amount of energy.
Nuclear power station
Efficient reactions become continuous only if there is a certain amount of fuel present, call the critical mass. In a nuclear reactor, rods contain uranium fuel. The fuel rods are placed close together to provide the critical mass that starts the reaction.
Biomass
On a global scale, biomass – vegetable matter used as a source of energy – meets a significant proportion of our energy needs. In Ethiopia, Tanzania and Nepal, for instance, it accounts for over 90%. In most other developing countries, wood, crop residues and animal dung provide over 40% of the fuel burnt. Such fuel is the only source of energy for cooking and heating for some 2000 million people. In many developing countries, the wood used as fuel comes mainly from unmanaged forestry, in which trees are felled but not replanted. There are developments under way, however, that will make both the production and the combustion of biomass more efficient. Crop residues, such as straw, which were once left to rot or burnt on the field, can now form the fuel for compact boilers used to heat farms or factories, to generate power, or to fuel industrial processes. Farmers particularly in the Third World are beginning to plant fast growing tree spices in forests or between rows of crops to provide a regular supply of firewood. Many tractors are being converted to be run on sunflower oil instead of diesel. Crops rich in starch and sugar can ferment to produce alcohol, which is added to petrol in many countries, notably Brazil to form what is known as ‘gasohol’.
RUBBISH
Domestic and commercial waste is expensive to dispose of in dumps, yet it could form a valuable fuel. A dry weight of 100 million tonnes (tons) of rubbish-perhaps a tenth of the total collected in USA each year-could replace about 15 million tonnes of coal. In Sweden there is already a scheme in operation known as ‘district heating’. Twenty-three refuse incinerators burn roughly half the country’s domestic refuse, and the energy produced rather than being used to generate electricity-is used to heat nearby homes and offices. Where waste is dumped into the ground, it can still yield useful energy. As rubbish decomposes, it produces methane (the principal component of natural gas). More than 30 large sites in the USA already extract gas from buried refuse dumps, and the technology is being introduced elsewhere. Even sewage can be used a source of energy. Millions of rural homes developing world have biogas plants. At there simplest, these consist of cement lined tanks buried in the ground, which, receive human waste or animal manure. Bacterial action produces methane, or ‘biogas’. An estimated 20 million people in China use it for cooking and heating.
SUNSHINE
Direct solar energy is one of the simplest sources of power. Building designs, old and new, take advantage of it for heating and lighting. Today, more active designs are becoming widespread. Each square meter (11 ¾ sq. ft) of a solar collector in Northern Europe receives roughly 1000 kilowatt-hours of solar energy in the course of the year, and can use about half of this energy to heat water. A similar collector in California receives twice as much energy as this. Solar (or ‘photovoltaic’) cells, which use the Sun’s radiation to generate electrical energy, are also becoming cheaper and more efficient. Earlier cells, made from large slices of crystalline silicon, were very expensive, but new materials amorphous silicon and gallium arsenidle, are bringing the price down toward the goal of about $1 per watt. The latest experimental solar cells are able to convert about the third of the energy from sunlight into electricity. Solar cells are already providing the best option for producing electricity reliably in remote locations.
WIND
The traditional windmill has tapped the energy of the winds for centuries. Its modern counterpart is far more sophisticated. The biggest ones have blades resembling giant aircraft propellers upto 60m (200 ft) across, and can generate 30 MW of electricity. Two such machines provide much of the electricity for Orkney Islands, and several large ‘windfarms’ have been built at coastal sites both in Europe and the USA. Another approach, pioneered in Britain, is a wind turbine with blades like a giant letter H, which rotate around a vertical axis. The mechanism tilts the blade tips inwards in high winds, thus regulating the supply.
WATER POWER
The average waves washing the North Atlantic coast of Europe is 50 kW per metre of wave front. Many ingenious techniques have been devised to harness this power, ranging from systems of rafts or floats known as ‘ducks’, rings of air bags known as ‘clams’, or columns in which water is forced up or down. Much effort has gone into the development of such techniques, but it has proved difficult to design structures capable of withstanding the force of the waves without excessive maintenance. It has become clear that wave power will not easily produce the hoped-for quantities of cheap energy. The power of running water has long been exploited by water mills-one of the most ancient means of harnessing the power of elements. In some countries, hydroelectric power, or ‘hydropower’ is the most important source of energy. Hydropower provides 8% of Western Europe’s energy, and worldwide it provides roughly as much energy as nuclear power. Major projects can be controversial as they may involve flooding environmentally sensitive areas. However, the latest design of low-head water turbines has reduced the necessary height difference (the ‘head’) between the turbine and the surface of the reservoir, so making it possible to build smaller barrages or even to place turbines directly into river beds. Tidal movements – ultimately derived from the Earth’s rotation are potentially a vast source of energy. Where tidal currents are funnelled into the river estuaries, there is an opportunity to harness this energy. There are currently six tidal power stations in the world, the biggest of them at Rance Estuary in Brittany, France. Proposed tidal power schemes across the Severn Estuary in Britain and the Bay of Fundy in Canada would be much bigger.
GEOTHERMAL POWER
Just 30 km (19 mi) beneath our feet, the rock has a temperature of around 900 C (1650 F). This heat comes primarily from the gradual radioactive decay of elements within the Earth. Strictly speaking, this source of power is not renewable, but it is immense. There is enough heat in the top 10 km (6mi) of the Earth’s crust, at depths accessible with current drilling techniques; to supply all our energy needs for hundreds of years. In some parts of the world, including Iceland, the amount of geothermal heat reaching the surface is distinctly greater than elsewhere, and can be used directly as means of domestic heating. In other countries, blocks of flats are heated by hot water from wells 2 to 3 km (1to 2miles) deep. The biggest reserve of geothermal heat, however are to be found deeper still, at 6km (4 miles) or so. As the rocks at this depth are dry, it is harder and more costly to get the heat out, because it is necessary to pump down water in order to bring the heat up. In an experimental project in Cornwall, England, three boreholes drilled to the depth of 2km (1 ¼ miles) have been interconnected with a system of cracks, allowing water to pump from borehole to another. There are plans to drill holes three times this depth, but even at current depths water returns to the surface hot enough to produce steam to drive turbines. Some estimates suggest that in Cornwall and other areas where the rocks are hotter and shallower depths, schemes of the kind could ultimately yield energy for Britain equivalent to 10 billion tonnes (tons) of coal.
HYDROELECTRIC POWER
Ina typical hydroelectric power plant, a river is dammed to create a reservoir that can provide a steady and controllable supply of running water. Water from the reservoir is channelled downstream to the powerplant, where it causes a turbine to rotate, which in turn drives an electric generator. Transformers at a substation then step up the electricity generated to the high voltage suitable for transmission. In areas where there are considered fluctuation in electricity demand, pumped- storage plant may be installed. The surplus power available at off-peak periods is used to pump water to a separate reservoir. At peak times, the stored water is released to generate extra electrical power.
TIDAL POWER
The tidal power station at La Rance in Brittany, France, opened in 1966, consists of a barrage blocking the 750-m (2460-ft) wide estuary of the River Rance. The tidal waters are channelled through 24 tunnels in the barrage. Each tunnel houses a reversible turbine generator that can operate efficiently both on the flood side (when the water flow is from the sea to the basin) and on the ebb tide (from basin to sea). At high, the sluices are closed, trapping the water in the tidal basin. The water can then be released to turn the turbines when the tide is low but when demand for power is high. Each of the 24 turbines can generate upto 10MW-the total output of the plant being sufficient to satisfy the needs of around a million consumers.
ENERGY IN THE FUTURE
No single form of renewable energy is likely to be as dominant in the future as oil and coal have been in the past. Taken together, however such sources could answer most of the world'’ needs, replacing fossil fuels as they run out or become environmentally unacceptable. If fuel saving measures such as improved insulation and waste-heat recovery are also widely implemented; it may that our energy needs will fall even as our prosperity grows.
SUMMARY
Overall fuel is a very important thing. Our lifestyles will be totally different without fuels because we would not have any electricity, gas etc. There are lots of people in this world who are suffering without fuels. I think in the future people would not realise the importance of fuel as we do now.
