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Energy sources :explode: (We can classify energy sources in several ways…
Energy sources :explode:
Uses:
Household uses: the operating of electrical appliances, heating systems, hot water systems, heat for cooking and for means of transport, for example.
Industrial uses: the operating of factories and companies, construction, agriculture and so on.
Definition: Energy sources are natural resources from which we obtain different forms of energy that can be transformed for a specific use. For example:
Hydraulic, geothermal, nuclear, wind power, solar, petroleum and its derivatives, coal, natural gas, biomass, tidal power
We can classify energy sources in several ways
By availability in nature and capacity for regeneration:
Renewable
Non-renewable
Electricity
Electricity is the most widely used form of energy in industrialised societies for two reasons.
It can be easily transformed into other forms of energy, such as
light and heat.
It can be transported long distances inexpensively and with very
little energy being lost.
2.1 Electric power plants
Definition: electric power plants are facilities where primary or secondary energy is transformed into electricity. Once electricity is generated, it must be transported to towns, cities or industrial parks.
How an electric power plant works: Electrical power plants use an external source of energy to produce electricity. To do this, they rely on a turbine-alternator system.
• The turbine converts mechanical energy into the rotating movement of a shaft.
An alternator has a fixed part, called a stator, and a moving part,
called a rotor, connected to the turbine shaft
2.2
TRANSPORT AND DISTRIBUTION OF ELECTRICAL ENERGY
Electric power plants are usually located far away from the points where the energy is used — for safety reasons, space requirements or physical and geographical considerations.
By origin:
Primary: Obtained from nature, for example natural gas .
By use in each country
Non-conventionah
Conventional
By environmental impact
Clean or non-polluting
Pollutants
3.Conventional electric power plants
This type of power plant produces most of the electricity that we use.
3.1. Nuclear power plants: This type of plant includes a nuclear fission reactor that produces the pressurised steam needed to move the turbine rotor. Uranium is the main fuel used.
3.2. Fossil fuel thermal power plants: At this type of power plant, water is heated in a boiler by the heat generated from the combustion of a fossil fuel, usually natural gas or coal. The steam that's generated moves the turbine connected to the generator.
Combined cycle power plant: Electricity is generated as a result of two combined cycles, a cycle that uses air and gas, and a conventional thermal cycle. During the first cycle, a gas turbine is used that includes a compressor. Air is mixed with the gas and is burnt, which generates electricity in the turbine-alternator system. The combustion gases are tranported to a boiler, where their transfer their energy to the water during the second cycle. This type of power plant performs better than those with only one cycle-
3.3. Hydroelectric power plants : This type of power plant uses
the potential energy provided by the height of the stored water in a dam, converting it into kinetic energy. This energy moves the blades of the turbine. Depending on the destination of the water, hydraulic power plants are divided into two types , gravity or pump.
Gravity-driven hydraulic power plants: water used follows the course of a river and will not be reused.
Pump-dniven hydraulic power plants: water descends into a reservoir located at a lower height, then pumped to a higher reservoir to reuse it
4.Non-conventional electric power plants.
The environmental problems caused by conventional power plants have led to the creation and development of non conventional or alternative energy power plants.
The main disadvantage of these power plants is that they generate much less energy, since they use diffuse energy sources. Their advantages are that they contaminate much less than conventional power plants, they use renewable sources and they reduce the energy dependence of petroleum and natural gas.
4.1. Wind power plants and wind farms: These power plants use the kinetic energy of the wind to move the blades of a rotor at the top of a tower, this is referred to as the wind turbine. Wind farms are a clean form of generating electricity. However, they
can only be installed in places with appropiate wind conditions.
4.2. Solar power plants: These plants use the energy from the sun. There are two main types of installations: photo-thermal and photovoltaic power plants. Photo-thermal power plant:
In this type of power plant, the heat generated by solar radiation produces steam that is used to move the rotor in the generator. Photovoltaic power plants : In these power plants, solar radiation is transformed directly into electricity by panels of photovoltaic cells.These power plants consist of large areas of photovoltaic panels. There are also isolated power plants that are very small in size , which are used to supply electricity to home~ in rural areas.
4.3. Geothermal power plants: These plants use the heat found at deep levels in the earth. This heat may reach the surface in the form of steam, gases or hot water. Geothermal energy may be used directly — for hot water and heating, industnal use and so on — and indirectly — the heat generates steam , which
produces electricity.
4.4. Biomass thermal power plants: Biomass consists of all organic compounds that are produced through natural processes. They may come from the following sources: Forestry and agricultural waste, specific crops, such as sunflowers and sugar beet and waste from agri-food industries. Biomass is subjected to different physical and chemical processes in order to produce fuel such as charcoal, alcohol or biogas.
4.5. Ocean power plants: These power plants use the energy from the seas and the oceans. The concept is to use three types of energy from the sea: the mechanical energy from the tides, the mechanical energy from the waves and the energy from the ocean's thermal gradient.
5.Environmental impact
The building and operating of an electrical power plant results in an ecological change in that region. This is due both to the construction of the necessary infrastructure and the waste that this activity generates.
5.1. Environmental impact assessment: As part of a technical project, it's mandatory to carry out an environmental impact assessment to find out what changes it would
provoke in the environment.
Fossil fuel thermal power plant
Nuclear
Hydroelectric
Wind power
Solar
Biomass
Ocean power
5.2. Environmental impacts: Energy consumption is preceded by a long process, consisting of several
stages, each of which has an environmental cost.
Extraction of natural resources
Fuel transport
Electricity generation
Hydroelectric power plants
Conventional thermal power plants
Nuclear thermal power plants
Final energy use
5.3. Waste treatment: to reduce the waste generated by thermal power plants, as well as their effects, several measures can be taken. Waste from nuclear power plants is stored in drums with thick sides that do not let the nuclear radiation escape.
Install special filters on the pipes at the power plant to capture some of the gas pollutants, use coal with a low sulphur content, to reduce acid rain, maintain and increase the size of large forested areas, since they absorb carbon dioxide.
5.4. Some solutions
Energy diversification
Energy savings
Efficiency
