Geothermal Energy
– energy from the Earth
Deep underground, the Earth’s rocks are naturally very hot. We can
turn their heat energy into electrical energy to use in our homes –
we call this ‘geothermal energy’.
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Cold water is pumped below the ground.
Hot rocks heat the water, turning it into
steam.
The steam is used to generate electricity.
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Renewable
No pollution, because nothing gets burned
Doesn’t damage the environment
No fuel cost
Reliable
Very few places in the world where you
can do this
Costs a lot of money to drill deep into
the ground
Can sometimes releases harmful gases
Possible earthquake or surface cracking
when drilling.
Wave Energy
– energy from sea waves
The sea’s waves have kinetic energy. Using machines that bob up and
down in the waves, this energy can be turned into electrical energy
which we can use in our homes.
wave energy
machines bobbing
up and down in the
waves
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Renewable
No fuel cost
Reliable
No pollution, because
nothing gets burned
– Need lots of machines to get a
reasonable amount of energy
– The machines costs a lot of money
– The machines can look ugly
– The machines can be damaged by
storms
– Can affect marine life
Hydroelectric Energy
– energy from rivers
The water flowing in a river has kinetic energy. We can turn this into
electrical energy to use in our homes. We usually need to build a
dam, and let the water flow through it gradually.
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Renewable
No pollution, because nothing gets burned
We can store the water up high, and then whenever
we need the energy we can let the water out
No fuel cost
Reliable
Immediate response to change in electricity demand
Cheap
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Costs a lot of money to
build a dam
The dam can ruin the
local environment,
because it changes where
the water naturally
flows. Some animals and
plants may die.
Can only be located in
suitable places
Tidal Energy
– energy from sea tides
If you’ve ever been to the coast, you may have noticed that the sea
level goes up and down, because of tides. When the tide is high, the
water has lots of gravitational potential energy, which we can turn
into electrical energy to use in our homes.
1.
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At high tide, we trap the water behind a
dam.
At low tide, the water is released, and its
energy is used to generate electricity.
+ Renewable
+ No pollution, because nothing
gets burned
+ Reliable, because there are
always two tides every day
+ Cheap to run, once it’s built
– Costs a lot to build the dam
– The dam may cause local flooding
Solar Energy
– energy from the Sun
The Earth gets heat and light energy from the sun all the time. Can
we use it – yes we can! The Sun’s energy can either be:
1. changed into electrical energy to use in homes, using solar cells;
2. or used to heat water for homes, using solar panels.
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Renewable
No CO2 or other air pollutants
No fuel cost
Easy to install
Little environmental impact when
located on buildings
– Solar cells and solar panels are
expensive
– Only works if it’s sunny!
Wind Energy
– energy from the wind
Using wind turbines, we can turn the kinetic energy of the wind into
electrical energy which we can use in our homes. This is ‘wind
energy’.
+ Renewable
+ No pollution, because nothing
gets burned
+ Turbines are quite cheap and
easy to build, so they can be
used even in poor countries
– Turbines can be ugly and noisy
– Only works if it’s quite windy!
If the wind stops, you get no
energy.
– Can be a threat to birds and
bats.
– Can only be located in suitable
places
Biomass Energy
–
energy from plants (Biofuel)
The chemical potential energy stored in things that were once alive
(e.g. trees) can be turned into heat energy by burning them. (We can
also turn it into electrical energy to use in our homes.)
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Trees absorb the sun’s energy. The trees
change this energy into chemical energy,
which they store inside themselves.
When we burn wood, we turn this energy
into heat, which is useful for cooking and
heating.
Renewable – as long as we keep planting
trees to replace the ones we cut down
Doesn’t need any special equipment, so it
can be used very easily, even in poor
countries
Large areas of land are needed to grow
enough trees
Releases CO2
Loss of habitat and space to grow crops
due to large amount of land needed.
Nuclear Energy
The main nuclear fuels are uranium and plutonium. In a nuclear power
station nuclear fuel undergoes a controlled chain reaction in the reactor to
produce heat - nuclear to heat energy.
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heat is used to change water into steam in the
boiler.
the steam drives the turbine (heat to kinetic
energy)
this drives the generator to produce electricity kinetic to electrical energy.
No pollution, because nothing gets burned
Can produce large amounts of electricity
from a small amount of fuel
A good way to use up uranium and
plutonium, rather than in bombs!
Reliable
Very few places in the world where you
can do this, as no one wants it on heir
doorstep.
Can be very dangerous if things go wrong
Waste is radioactive for thousands of
years.
Fossil Fuel Energy
In a thermal power station fuel such as coal, oil or gas is burned in a
furnace to produce heat - chemical to heat energy.
1. this heat is used to change water into
steam in the boiler.
2. the steam drives the turbine - heat to
kinetic energy
3. this drives the generator to produce
electricity - kinetic to electrical energy.
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Industry set up already to process this
energy
Easy to use
Will run out someday – non renewable
Releases CO2 and other air pollutants
Prices are rapidly increasing.
New drilling by fracking can cause
environmental problems to water and
animals in surrounding area.