S6 UNIT 10
Overview
this unit 10 aims to equip learners with ability to evaluate the success of sustainable development projects in power and energy production in different parts of the world.
UNIT 10: POWER AND ENERGY PRODUCTION IN THE WORLD
UNIT 10: POWER AND ENERGY PRODUCTION IN THE WORLD
Power refers to the capacity to do work or make things much easier.
Energy refers to any source of usable power such as solar, hydroelectric power, wind, petrol and others.
10.1. Sources and forms of energy used in the world
Classification of energy resources
- Renewable energy resources: these are natural resources which ae not exhausted when they are used. They are continuously replaced by nature. These are land, soil, water, animals and wildlife, sunshine.
- Non-renewable resources: these are resources which diminish and get exhausted when used or exploited. For example, Crude oil and natural gas
10.1.2. Non-renewable energy sources
Non-renewable energy resources are available in limited supplies. This is usually due to the long time it takes for them to be replenished.
a) Nuclear energy (Uranium)
Nuclear energy is energy obtained from uranium through a chain reaction. When it was realized that when the nucleus of an atom is bombarded by electron it disintegrates and releases enormous quantity of energy, two thoughts came in the mind of rational man:
- to build an atomic weapon, and;
- to generate electricity.
Thus, mankind has developed the art of both. The release of energy by this process is known as fission. Based on this process scientists build reactors in which controlled fission went on to produce energy (heat) and this heat generated electricity.
b) Coal
Coal is a sedimentary deposit formed by the slow action of heat and pressure on plant remain buried in the long past. It is a mechanical mixture of carbon, hydrogen, nitrogen, Sulphur.
i)Types of coal
The amount of fixed carbon and hydrocarbons forms the basis of classification of coal into various types.
- Anthracite: It is a hard and dense coal which is relatively free from iron compounds and moisture. It is made by 95 % of carbon.
- Bituminous: The moisture content is relatively low. The fixed carbon content ranges from about 50 to over 80% and that volatile matter from 40 to 15%.
- Lignite: It is also known as brown coal. The higher grades vary from dark brown to almost black. It is characterized by high moisture content, generally about 40%. The fixed carbon content is also 40%. The structure is fibrous, and sometimes woody.
- Peat: It occurs in bogs(swamps), especially in areas of cool temperate climates. This is young coal which consists of partly decomposed vegetation.
ii. Uses of coal
- in thermal generators to produce thermal electricity.
- as a domestic fuel for heating and indirectly in the form of a gas and electricity.
- in iron smelting e.g. through use of metallurgical coke in blast furnaces.
- to provide a number of raw materials for the chemical industries like coal gas, coal tar, benzele and sulphate of ammonia.
c)Petroleum (oil)
Petroleum is an inflammable mixture of oil hydrocarbons with very complex properties. Petroleum literally means ‘rock oil.’ It exists underground in solid, liquid and gaseous form. Accumulations of petroleum are found in underground fields, pools or reservoirs of sedimentary rock formations.
Three grades of crude oil according to gasoline yields
- Paraffin: base oil has high percentage of methane (highest yields)
- Mixed-base: oil has high percentage of naphthene (intermediate yields)
- Asphalt - base oil has heavier hydrocarbons (lowest yield)
Uses of petroleum
- for heating homes and hearths;
- as industrial power to drive/move engines and for heating furnaces and producing thermal electricity;
- as transport power for driving railways, motorcars, ships and aeroplanes;
- as lubricants of machines especially high-speed machines;
- as a raw material in various petro-chemicals industries, such as synthetic rubber, synthetic fibres, fertilizers, medicines.
10.1.3. Renewable energy resources
Renewable energy is the energy which comes from natural resources that are naturally replenished such as sunlight, wind, water from rivers, biogas, geothermal heat and tides which naturally replenish themselves.
a) Hydroelectric power(water energy)
This is the energy produced from running water. Usually a dam is constructed across a river to store water. China is the largest producer of HEP, followed by Canada, Brazil and USA. The water is then made to fall over a steep gradient. It then passes through a turbine hence spinning the blades of the turbine. Rotation of th e blades cause the turbine to turn an electric generator that produces electricity.
Hydro-electrical power energy requires the following physical and economic conditions:
i. Physical conditions
- A seismological less sensitive area.
- High quantity of water supplied by fairly heavy rainfall distributed throughout the year.
- Great altitude with steep slope to enhance water velocity.
- Existence of rapids and falls favour the development of power by increasing the velocity of stream.
- Narrow steep-sided valley to facilitate dam construction.
- A hard rock for firm foundation.
- Existence of lakes or space for water reservoir.
- The absence of coal, petroleum, etc., expedites the development of waterpower.
ii. Economic Conditions
- Market: Large demand for hydroelectric power;
- Huge capital outlay;
- Technological knowledge and skill and
- Transport facility.
Advantages
-Once built, the supply of electricity is relatively cheap
-Large dams become tourist attractions
-The reservoirs (lakes) that form behind the dam can be used for water sports, leisure and pleasure activities,
-The water in the reservoir can be used for used for irrigation purpose and fishing.
-Power dams control flooding.
Disadvantages
-Dams are very expensive to build
-The buildings of large dams, floods large areas and destroys existing wild life and causes the damage to habitats of any creatures living in the area.
-Changing the flow of a river will affect the water supply to lands nearer the sea. The may cause problems of irrigation for crops.
-The fertile silt that usually flows down to the floodplains and deltas is blocked by the dams
-Damming destroys the beauty of rivers and affects tourism.
b) Solar energy: is a form of power tapped from direct rays of the sun using solar panels. A greenhouse uses panels of transparent glass to trap solar energy. Another way of tapping solar energy is by use of solar cells. This transforms sunlight directly into electricity.
c) Wind energy: wind energy is renewable form of energy generated from wind. This is widely used in Europe (Denmark, Portugal, Spain, Ireland and Germany), Asia, United States. the process of the production of energy from the wind is the following: usually a propeller blade is mounted on a tower. The blade is connected onto an electric generator. As wind blows, the blade spins and turns the generator which produces electricity by converting the kinetic energy of the wind into electric energy. A suitable site for a wind turbine depends on the local wind conditions.
d) Energy from biomass: is the oldest source of renewable energy, used since our ancestors learned the secret of fire. This is the energy produced from materials of living things. This could be plant material, animal material. The generation of energy starts through the process of photosynthesis. Through this process, chlorophyll in plants captures the sun’s energy by converting carbon dioxide from the air and water from the ground into carbohydrates—complex compounds composed of carbon, hydrogen, and oxygen. When these carbohydrates are burned, they turn back into carbon dioxide and water and release the energy they captured from the sun. Bio-mass energy includes: wood fuel, Bio-gas and Gasohol.
- Wood fuel: This is a very important source of energy in third world countries. The wood obtained from forests is either used directly or converted to charcoal.
- Waste products (Bio-gas): This is a flammable gas produced by microorganisms, when organic matter is fermented under specific temperatures, moisture content and acidity.
- Gasohol: Plant material may be converted to alcohol which is a fuel.
Wood, wood wastes and garbage can be heated to produce methanol. Most plants containing starch and sugar like sugarcane and cassava can be converted to ethanol. Corn, corn stalks, manure and sewerage can be fermented and distilled to give ethanol. Both methanol and ethanol are directly burned as a fuel.
e) Geothermal energy: Geothermal energy is produced when rocks lying deep below the earth’s surface are heated to high temperatures by energy from the decay of the radioactive elements in the earth and from magma. Geothermal energy can be considered as renewable source of energy if deep underground heat flows can be tapped.
Geothermal energy can either be used for heating water, directly and space heating needs in agriculture and for domestic purposes or it can be converted into electricity.
f) Tidal energy: is a form of hydropower that converts the energy obtained from tides into useful forms of power, mainly electricity. Although not yet widely used, tidal energy has potential for future electricity generation.
As the tide rises and falls water flows into and out of bays and estuaries. If the bays and the estuaries can be closed by a dam the energy in the tidal flow can be extracted four times a day and used to spin a turbine to produce electricity.
Although all coastal areas are subject to some tidal changes, only those few areas with a large enough tidal range of some four to five meters are potential sites for tidal power plants.
10.2. Factors favouring power and energy production in the world
There are:
- Availability of market
- Availability of capital
- A high degree of technical knowledge and skills
- The amount of energy to be produced
- Presence of waterfalls
- Natural environment area where the energy will be produced.
10.2.2. IMPORTANCE OF POWER IN THE DEVELOPMENT OF THE WORLD
- It is used in industries and settlements for lighting and heating purposes
- It is a source of income to the government/earn foreign exchange: it can be exported
- It is a source of employment opportunities to many people directly or indirectly
- There are tourist potentials as they attract different tourists and foreign investors
- They facilitate the growth and development of industries
- They facilitate the growth of towns and other urban centers
- They help in the development of trade and commerce.
- It improves the standard of people
10.3.1. Problems hindering power production and supply in the world
- There is high demand for power due to rapid growth of heavy industries and urbanization
- Many waterfalls are not yet exploited due to seasonal changes
- Inadequate capital to invest in power production and maintenance
- No feasibility study in accessibility, exploitation and marketing of power services
- Lack of technical knowledge
- Over dependence on oil and its products
- Economic and political embargoes fixed by the rich countries
- Increase in oil prices imposed by Oil Producing and Exporting Countries (OPEC)
- Wastage and misuse of energy
- Depletion of wood fuel due to over exploitation of forests
- Exhaustion and deepening of coal mines.
- Environmental pollution
- To seed alternative sources of energy
- Development of renewable sources of energy like solar power, wind energy, geothermal, biogas, water energy.
- The government may come in and improve on public transport efficiency so as to reduce the need to use personal vehicle to reduce the use of petroleum.
- Switching off electricity gadgets when not in use.