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Energy and its transformation, image, image, image, image, image, image,…
Energy and its
transformation
Energy source
The energy we consume has many different uses
Household uses
the operating of electncal appliances, heating systems, hot water systems, heat for cool.ing and for means of transport, for example.
Industnal uses
the operating of factones and companies, construction, agnculture and so on.
Energy sources are natural resources from which we obtain different forms of energy that can be transformed for a specific use
We can classify energy sources in several ways
By availability in nature and capacity for regeneration
Renewable
Abundant and inexhaustible
Non-renewable
May or may not be abundant
Depleted when we use them up
Cannot be renewed in a short period of time
By origin
Primary
Obtained directly from nature
Examples, crude oil, natural gas, coal, nuclear energy and renewable energies
Secondary
Resulting from transformation of pnmary sources
Examples; electricity, some petroleum denvatives
By use in each country
Conventional
Most commonly used in mdustrialised countnes
Example energy that comes from fossil fuels
Non-conventional
Alternauve energy sources
In early stages of their technological development
Solar and wind power belong to this group
By environmental impact
Clean or non-polluting
Low environmental impact
Don't generate by-products that pollute the environment
Pollutants
Sources that have negative effects on the environment,
for example, they might generate by-products that severely pollute the environment.
Below is the classification of the energy sources studied in this unit
Electricity
Electricity is the most widely used form of energy m industnalised socieues for two reasons
It can be easily transformed into other forms of energy
It can be transported long distances inexpensively and with very
httle energy being lost
Electric power plants
How an electric power plant works
Electncal power plants use an external source of energy to produce electncity 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
Electric power plants are facilities where pnmary or secondary energy is transformed into electnmty, Once electricity is generated, it must be transported to towns, cities or industrial parks.
. Transport and distribution of electrical energy
electric power plants are usually located far away from the points where the energy is used — fur safety reasons, space requirements or physical and geographical considerations
Electncity cannot be stored; therefore, it must be transported to
consumption centres This transport involves several processes:
Increasing the voltage to 220 000 V or 400 000 V to prevent signifcant energy loss, due to the Joule effect
Transporting it by high voltage cables attached to towers
Decreasing the voltage at the electncity substations to 3-30 kV
Distnbution to homes, offices, industnes and public faolities During this srage, the voltage is reduced to 230-400 V.
Conventional electric power plants
This type of power plant produces most ot the electnctty that we use
Nuclear power plants
This type of plant tm.ludes a nuclear fission reactor that produr.es the pressunsed steam needed to move the turbine rotor.
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
Efectricity ts generated as a result of two combined cycles, a cycle that uses air and gas, and a conventional thermal cycle Dunng the first cycle, a gas turbine is used that includes a compressor. Air is mixed with the gas and is burnt, which generates electncity in the turbine-alternator system.
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 mto kinetic energy. Tlus energy moves the blades of the turbine
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
The ir advantages are that they contaminate much less than
conventional power plants
Wind power plants and wind farms
These power plants use the kinetic energy uf the wind to move
the blades of a rotor at the top of a tower, this is referred to as the
Solar power plants
These plants use the energy from the sun There are
two main types of instaflations: 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 plant
In these power plants, solar radiation is transformed directly into electncity by panels of photovoltaic cells.
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.
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 cougar beet.
kyraste from agri-food industries
Biomass Is sublected to different physical and chemical processes morder to produce fuel such as charcoal, alcohol or biogas.
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.
The energy from the ocean's thermal gradient
Environmental impact
The building and operating of an ecological 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.
Environmental impact assessment
The main characteristics of each type of power plant and the impact
they have on the environment are shown below
Environmental impacts
Energy consumption is preceded by a long process, consisting of several stages, each ol which has an environmental cost.
Extraction of natural resources
The exploitation of fossil fuels and nuclear power means the depletion of resources, which makes it necessary to find new ones
Fuel transport
Oil is transported by means of oil pipelines and oil tankers.
Oil pipehnes can suffer accidents caused by nature or human error, which result in uncontrolled spills.
Electricity generation
Large hydroelectric power plants require water reservoirs covenng large areas, which protoundly change the natural cycle of overs, flood large land areas and destroy ecosystems, in addition to increasing the nsk of accidents.
Conventional thermal power plants can cause numerous problems and environmental hazards.
They produce air pollution — suspended particles, CO, heavy
metal molecules and so on.
They emit large amounts of COa which increases rhe greenhouse
effect.
They emit sulphur dioxide and nitrogen oxide that cause acid
rain, which is very harmful to the environment
The water used in the cooling system is returned to ihe environmem
while it's sull warm, which affects both animal and plant life
Nuclear thermal power plants are accompanied by the nsk of
nuclear accidents and the problem of nuclear waste, some of which remam dangerous for thousands of years
Final energy use
The fuels we use in vehicles and heating systems emit gases and particles similar to those generated by convenuonal thermal power plants.
Waste treatment
To reduce the waste generated by thermal power plants, as well as their effects, several measures can be taken
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.**
Waste from nuclear power plants is stored in drums with thick sides that do not let the nuclear radiation escape
Some solutions
Below is a summary of different possible solutions to alleviate some of the environmental problems descnbed
These power plants consist of large areas of photovoltaic panels
