Unit 2: Energy and the environment
2.1 Fossil fuels
The world population uses energy by direct combustion (burning) to produce heat and light.
Combustion requires a suitable fuel source w/ large amounts of carbon.
● There are sources that are “energy dense” producing a great amount of heat from a
unit of fuel (natural gas, coal, oil) called fossil fuels.
● Fossil fuels are produced from the decay of plants and animals that formed organic
matter that become covered in layers of sediment. The organic material was
subjected to great pressure and heat, the precise conditions and the type of animal
and plant material available, determined whether coal, oil or natural gas is produced.
● The dead remains from animals and plants are buried under layers of sediment, so
extracting involves digging or drilling underground.
● The length of time needed to create fossil fuels means that there’s a limited supply.
2.2 Energy sources
● The demand for fossil fuels increases because of increasing population size,
increasing industrialization and urbanisation or improvements in standard of living
and expectations.
● Energy sources can be described by whether they’re limited sources (non-
renewable) as they cannot be replaced, or unlimited sources (renewable) as they can
be used over and over again.
How energy sources are used
Most electricity is generated by electromagnetic induction, this transforms kinetic energy
(made from movement) into electrical energy, using loops of a conducting material such as
copper and a magnet. As the coils are rotated close to the magnet, electricity is generated. A
turbine connected to the generator is used to rotate the coils, they are designed to do the
rotary motions needed in the generator, this is typically done by passing a stream of gas or a
liquid over the turbine blades.
Geothermal power: Cold water is pumped under pressure into a layer of hot rocks, that
heat the water and. The now hot water returns to the surface under pressure and heats up a
second supply of water using a heat exchanger. The steam produced in the second supply
moves the turbine, which generates electricity in the generator. Water can be re-used in this
process.
Solar power: Electricity produced by this method uses photovoltaic cells, they all work on
the principle that certain materials produce small electric charge when exposed to the light.
A bank of cells organised into solar panels and organised into a solar array can produce a
significant amount of electricity.
Tidal power: Use natural rise and fall in the level of water in an area during a day. As the
level drops, water is held back by a tidal barrage that releases water back through a turbine
that generates the electricity, the amount of power depends on the charge in tide level
throughout the day.
Wave power: Uses a turbine and a generator to generate electricity. Power is produced by
channelling the energy of waves at sea. Water power is not limited to the regular pattern of
the tides, but electricity generation stops when there’s a calm weather condition (no wave
production).
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, Using the different energy sources
Deciding which energy source to use is not easy because you have to take in consideration
the economic, social and environmental impacts.
● Economic factors: Supply of energy is expensive, specially when demand is
increasing and the supply is limited. If a fuel is in high demand but short supply, the
price will rise. If a country has its own fuel supply, it can use this more cheaply than
importing other sources. Countries that have naturally occuring sources can take
advantage of high amounts of sunlight or geothermal energy.
For some countries there’s an economic barrier that prevents them from using certain
energy sources.
● Social factors: The mining of an area for coal or drilling for oil might mean the land
will no longer be available for agricultural use, but for the new industries might mean
greater local employment. The increase in industry locally might mean that other
businesses are needed to supply the needs of the energy business. The
development of large-scale projects could provide improvements to the local
infrastructure, but also energy business could cause the displacement of a whole
community. The development of new technologies could bring new manufacturing
opportunities but the working sector could start to decline. The investment of new
energy sources might also have health effects for the local population.
● Environmental factors: The spillage of fuel into the environment can cause damage
to wildlife, burning fossil fuels can produce toxic gases and waste products. Changes
to the ecosystem, the extraction of fossil fuels can destroy habitats. Renewable
sources can cause damage too, the damming of a river for hydroelectric power
generation can affect the ability of fish to breed. There’s also a visual impact on an
area’s natural beauty in large areas of solar panels or wind turbines.
Fuel type Advantages Disadvantages
Fossil Fuels - Plentiful supply in some - CO₂ and toxic gases when
locations burnt
- Provides jobs - Damages local area
- Available for most - Limited supply: prices rise
countries as supplies decrease
Nuclear power (using - Doesn’t produce CO₂ - Risk of radiation leakage
uranium) - Small amount of fuel = - Waste can’t be recycled
large amount of energy - Limited supply
Biofuels (bioethanol, biogas, - Renewable source: - CO₂ and toxic gases
wood) bioethanol and wood are produced when burnt
obtained from plants, biogas - Land is needed to grow
from the recycling of waste plants for fuel
- Growing more plants uses - Removal of natural
CO₂ ecosystems for plants to
- Potentially a plentiful grow
supply
Geothermal power - Doesn’t produce CO₂ - Expensive to install
- Unlimited supply - Only certain areas have
suitable conditions
Hydroelectric power - Doesn’t produce CO₂ - Building of dams impacts
- Water can be reused for the natural flow of water
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2.1 Fossil fuels
The world population uses energy by direct combustion (burning) to produce heat and light.
Combustion requires a suitable fuel source w/ large amounts of carbon.
● There are sources that are “energy dense” producing a great amount of heat from a
unit of fuel (natural gas, coal, oil) called fossil fuels.
● Fossil fuels are produced from the decay of plants and animals that formed organic
matter that become covered in layers of sediment. The organic material was
subjected to great pressure and heat, the precise conditions and the type of animal
and plant material available, determined whether coal, oil or natural gas is produced.
● The dead remains from animals and plants are buried under layers of sediment, so
extracting involves digging or drilling underground.
● The length of time needed to create fossil fuels means that there’s a limited supply.
2.2 Energy sources
● The demand for fossil fuels increases because of increasing population size,
increasing industrialization and urbanisation or improvements in standard of living
and expectations.
● Energy sources can be described by whether they’re limited sources (non-
renewable) as they cannot be replaced, or unlimited sources (renewable) as they can
be used over and over again.
How energy sources are used
Most electricity is generated by electromagnetic induction, this transforms kinetic energy
(made from movement) into electrical energy, using loops of a conducting material such as
copper and a magnet. As the coils are rotated close to the magnet, electricity is generated. A
turbine connected to the generator is used to rotate the coils, they are designed to do the
rotary motions needed in the generator, this is typically done by passing a stream of gas or a
liquid over the turbine blades.
Geothermal power: Cold water is pumped under pressure into a layer of hot rocks, that
heat the water and. The now hot water returns to the surface under pressure and heats up a
second supply of water using a heat exchanger. The steam produced in the second supply
moves the turbine, which generates electricity in the generator. Water can be re-used in this
process.
Solar power: Electricity produced by this method uses photovoltaic cells, they all work on
the principle that certain materials produce small electric charge when exposed to the light.
A bank of cells organised into solar panels and organised into a solar array can produce a
significant amount of electricity.
Tidal power: Use natural rise and fall in the level of water in an area during a day. As the
level drops, water is held back by a tidal barrage that releases water back through a turbine
that generates the electricity, the amount of power depends on the charge in tide level
throughout the day.
Wave power: Uses a turbine and a generator to generate electricity. Power is produced by
channelling the energy of waves at sea. Water power is not limited to the regular pattern of
the tides, but electricity generation stops when there’s a calm weather condition (no wave
production).
Página 1 | 7
, Using the different energy sources
Deciding which energy source to use is not easy because you have to take in consideration
the economic, social and environmental impacts.
● Economic factors: Supply of energy is expensive, specially when demand is
increasing and the supply is limited. If a fuel is in high demand but short supply, the
price will rise. If a country has its own fuel supply, it can use this more cheaply than
importing other sources. Countries that have naturally occuring sources can take
advantage of high amounts of sunlight or geothermal energy.
For some countries there’s an economic barrier that prevents them from using certain
energy sources.
● Social factors: The mining of an area for coal or drilling for oil might mean the land
will no longer be available for agricultural use, but for the new industries might mean
greater local employment. The increase in industry locally might mean that other
businesses are needed to supply the needs of the energy business. The
development of large-scale projects could provide improvements to the local
infrastructure, but also energy business could cause the displacement of a whole
community. The development of new technologies could bring new manufacturing
opportunities but the working sector could start to decline. The investment of new
energy sources might also have health effects for the local population.
● Environmental factors: The spillage of fuel into the environment can cause damage
to wildlife, burning fossil fuels can produce toxic gases and waste products. Changes
to the ecosystem, the extraction of fossil fuels can destroy habitats. Renewable
sources can cause damage too, the damming of a river for hydroelectric power
generation can affect the ability of fish to breed. There’s also a visual impact on an
area’s natural beauty in large areas of solar panels or wind turbines.
Fuel type Advantages Disadvantages
Fossil Fuels - Plentiful supply in some - CO₂ and toxic gases when
locations burnt
- Provides jobs - Damages local area
- Available for most - Limited supply: prices rise
countries as supplies decrease
Nuclear power (using - Doesn’t produce CO₂ - Risk of radiation leakage
uranium) - Small amount of fuel = - Waste can’t be recycled
large amount of energy - Limited supply
Biofuels (bioethanol, biogas, - Renewable source: - CO₂ and toxic gases
wood) bioethanol and wood are produced when burnt
obtained from plants, biogas - Land is needed to grow
from the recycling of waste plants for fuel
- Growing more plants uses - Removal of natural
CO₂ ecosystems for plants to
- Potentially a plentiful grow
supply
Geothermal power - Doesn’t produce CO₂ - Expensive to install
- Unlimited supply - Only certain areas have
suitable conditions
Hydroelectric power - Doesn’t produce CO₂ - Building of dams impacts
- Water can be reused for the natural flow of water
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