SOURCES OF ENERGY

ENERGY

CHAPTER 6

SOUCES OF ENERGY

SOURCES OF

ENERGY

Firewood

Fossils fuel

Hydroelectric energy

Wind energy

Wave energy

Biomass energy

Solar energy

Geothermal energy

Energy from radioactive substances

Hydroelectricity – electricity generated using water

Hydroelectric power – generated by forcing moving water to produce electricity.

Water flowing from a dam has potential energy.

This energy can be used to rotate turbines and dynamos to generate electric energy at a hydroelectric power station.

Water falling from a great height has a lot of potential energy that can be used to drive turbines that generate electricity.

Hydroelectric energy

Hydroelectric energy

Wind – moving air that contains kinetic energy. Windmills – for pumping water /grinding grains.

- used for centuries to convert wind energy into chemical energy; to drive machine.

Wind turbine – uses energy from the wind to generate electricity.

Wind has kinetic energy that is used to rotate windmills for the purpose of

a) Grinding wheat b) Pounding maizec) Pumping water for the use of animals and irrigation.

Wind energy

The sea rises and falls twice a day. Tide – the rising and falling of the sea level Wave have kinetic energy and potential energy used to

rotate turbines of dynamos in wave-generated power stations.

Not widely used because the electric energy produced is not constant but follows the condition of the sea.

The difference in height of the water at high tide and low tide is used in a tidal power station to generate electricity.

As the tide comes in, water flows through turbines to generate electricity .

When the tide goes out, water flows in opposite direction.

Wave energy (Tidal energy)

Used to describe energy that comes from biological materials such as animal faeces, plants and household wastes.

Decaying organic substances produce methane gas.

Ethanol is obtained from fermented plant materials.

Also can be obtained by burning rubbish; producing heat energy.

Used as fuel for producing heat, working machines and moving vehicles.

Biomass energy

Energy derived from the Sun. Heat and light are 2 forms of solar energy. Solar cells absorb light energy from the Sun

directly, change it into electrical energy. Solar cells are used to provide electricity for:

a) Calculators b) Satellites c) Watches d) Certain vehicles

Solar heater – change energy from the Sun into heat energy which then used for:

a) Heating up water b) Cooking purposes

Solar energy

Obtained from trunks, branches and twigs of trees.

Most firewood is used in rural area as fuel for cooking.

Produces a lot of soot that pollutes the environment.

Firewood

Combustible materials – they burns easily to release heat and light energy.

Supply almost 90% of fuel energy today – most widely used fuel.

Examples of fossil fuels: a) Oils (petroleum / crude oil)b)Natural gas c) Coal

Most fossil fuels used in power stations to generate electricity.

Fossil fuel

Comes from the very hot interior of the Earth in the form of heat energy.

Most geothermal areas are neara) volcanos b) hot spring c) geysers

Geothermal energy can bea) A tourist attraction b) A direct source of heating c) Used as an instant steam-generating facility to spin a

turbine. Water under the Earth is heated and then pumped out

to a) Heat buildings b) generate electricity

Geothermal energy

Geothermal energy

The uses of geothermal energy

Radioactive substances like uranium and plutonium can be used to produce nuclear energy.

Nuclear reactions generate lots of heat energy that can be used to generate electricity.

Splitting of atoms in radioactive substances release heat that can be used to produce steam.

Steam turns turbines and dynamos to generate electricity.

Energy from radioactive substance

Energy from radioactive substances can be used to generate electric energy fora) Ships b) Submarines c) Satellites d) Meteorological stationse) Lighthouses

Radioactive wastes are dangerous because they give out radioactive radiation that is hazardous.

Energy from radioactive substance

Sources of energy in the world can be classified into 2 groups:

Renewable energy sources – those that can be replenished or renewed when they have been used OR energy sources which cannot be depleted despite continuous use.

Non-renewable energy sources – those that cannot be replenished or renewed and will eventually be used up and exhausted OR energy sources which will be depleted one day and we will not be able to replace them.

RENEWABLE AND NON-RENEWABLE ENERGY

Nursyazwani binti Shawal

Sources of EnergyRenewable Non-renewable

•Hydroelectric (moving water)

•Fossil fuels (coal, petroleum, natural gas) – not last long

•Wind energy •Radioactive substances (nuclear energy) – last a long time

•Wave energy •Biomass energy •Solar energy •Firewood •Geothermal energy

Renewable and Non-renewable Energy

Renewable energy sourcesHydroelectric energy Advantages:

The electricity produced is cheap and does not pollute the environment.

Disadvantages: Dams and power stations are expensive to

build. Only suitable in mountains areas with good

rainfall. Large dams destroy habitats.

Renewable energy sourcesWind energy Advantages: Does not pollute the environment. Free

Disadvantages: Wind turbines stop working if there is no wind. Speed and direction of wind unrelieable Many wind turbines are needed to generate the

same amount of energy as one fossil fuel power station.

Renewable energy sourcesWave energy / Tidal energy Advantages:

Does not pollute the environment. Occur daily and always present

Disadvantages: Only generates electricity twice a day during

high and ebb tides. Waves vary in strength Expensive to build the power station

Renewable energy sourcesBiomass energy Advantages:

Reduce environmental burdens / waste organic matter

Cheap sources of energy

Disadvantages: Releases gases such as carbon dioxide and

sulphur dioxide that pollute the environment. Requires a large amount of biomass Takes up a large area

Renewable energy sourcesSolar energy Advantages:

Can be produced continuously. Does not pollute the environment.

Disadvantages: Expensive to install solar panels Depends on whether conditions

Renewable energy sourcesFirewoodAdvantages:

Can be used in areas that lack energy supply for cooking.

Disadvantages: Releases soot which pollutes the

environment.

Renewable energy sourcesGeothermal energy Advantages:

Does not pollute the environment. Plentiful supply of heat

Disadvantages: Only available where hot water is located close to

the Earth’s surface. Harmful substances present in the steam, e.g.

sulphur dioxide Expensive to build a power station

Non-renewable energy sourcesFossil fuelAdvantages:

High energy value / release a lot of energy Easy to burn

Disadvantages: Produces gases that are poisonous (like

sulphur dioxide) and form acid rain. Pollute the environment Coal produces a lot of soot

Non-renewable energy sourcesRadioactive substanceAdvantages:

Very high energy value / supplies plenty of heat energy

Disadvantages: Gives off harmful radiation that can cause cancer. Very expensive to build nuclear power stations. Danger of accidents Suitable radioactive elements not easily obtained

Sources of EnergyPollute the

environment Do not pollute the

environment•Fossil fuels (coal, petroleum, natural gases)

•Hydroelectric energy

•Radioactive substances (nuclear energy)

•Wind energy

•Biomass •Wave energy •Firewood •Solar energy

•Geothermal energy

Renewable and Non-renewable Energy

Solar cells Solar cells absorb sunlight and convert it into electrical energy to operate calculators

Solar heaters Solar panels are placed on the roofs of houses for absorbing heat from the sun. the heat is used for heating water in hot water systems

Solar cookers In hot countries, solar cookers concentrate the Sun’s rays to obtain heat for cooking

Solar power stations Solar panels are used to absorb the Sun’s heat for boiling water. The steam produced is used for turning turbines which drive generators for producing electricity

Uses of Solar Energy

Telephone in rural areas Some rural areas are installed with telephones which are operated by solar cells

Satellites Solar panels on satellites absorb sunlight and change it into electrical energy for operating the satellites

Photosynthesis Green plants absorb light energy from the sun and use it to make food by photosynthesis. In this way, solar light energy is converted into chemical energy

Uses of Solar Energy

To save non-renewable sources of energy such as fossil fuels (oil, gas, coal) from depletion as the supply is limited; but widely used all over the world.

To reduce the amount of money spent on electricity, gasoline (minyak petrol) and other forms of energy.

To protect our high standard of living which is due (in part) to our abundant energy sources.

To reduce the ‘side effects’ of energy use: pollution, damage to animal habitats and ruined landscapes.

Reasons we should conserving energy are:

More efficient equipment must be invented so that energy can be used more economically.

Develop the use of renewable energy sources to replace non-renewable energy sources.

Use non-renewable energy sources in an economical, efficient and smart way.

New fuels such as diesel and palm oil, and other renewable energy sources like hydroelectric energy, biomass energy, wind energy and wave energy should be widely used as alternative energies.

Ways to use energy efficiently

Since the Earth has limited amounts of non-renewable energy sources like fossil fuels, they must be conserved in order to avoid: Future energy crisis due to shortages or overuse

of fossil fuels. A growing exploitation of natural resources. Atmospheric contamination that causes global

warming and climatic changes, acid rain and smog. The resulting impact damages water sources e.g. groundwater, soil, crops, wildlife and wildlife habitats, building materials and human health.

Importance of Conserving Energy Sources

Recycle material Develop more efficient engines that use

less energy to operate.Put emphasis (penegasan/penekanan) on

the use of renewable energy sources such as solar energy.

Ways to use and manage energy sources efficiently: