Sources of Energy Blog 3

SOURCES OF ENERGY 

Lesson 3

 

Good Morning All !

Learning outcomes :

develop the concept of non conventional energy sources

• energy from the sea ,
• geo thermal energy ,
• nuclear energy 

list the significance of the above resources.

Energy From the Sea

The seas and oceans and other water bodies are a source of kinetic and potential energy due to the immense volume of water and the motion of waves.

Tidal energy

• Tides are variations in the level of water due to the gravitational pull of the moon.
• The phenomenon of rise and fall of water level or high and low tide gives tidal energy.
• Tidal energy is obtained by constructing dams near the narrow openings of the sea. When the tide sets in, it moves the turbine which directly produces electricity.
• It is limited to places near the sea.

Wave energy

• Waves possess a lot of kinetic energy that can be harnessed to produce electricity.
• Waves are produced by strong winds blowing over the sea.
• Limited to places with strong winds. Devices have been designed to capture this energy.

Ocean thermal energy

• The difference in surface temperatures of water and water at a certain depth in oceans is exploited to harness this form of energy.
• Temperature difference must be ${20}^{\circ }$ between the surface and water up to depths of 2 km.
• Warm water is used to boil volatile ammonia to form vapours that move the turbine. Cold water is used to condense the vapour back to liquid.

Geothermal energy

• There is a huge amount of heat trapped inside the earth. Molten rocks from Earth’s core sometimes come up due to geological changes and get trapped in hotspots. Harnessing this heat energy is called geothermal energy.
• Any underground water present gets heated due to the hotspots and gets converted to steam which escapes from the surface of the earth as hot springs.
• This steam is used to rotate turbines and generate electricity.

ADVANTAGES OF GEOTHERMAL ENERGY

    •  Renewable

    •  Inexpensive

DISADVANTAGES OF GEOTHERMAL ENERGY

    •  Only available in few sites

Nuclear Energy

• Nuclear energy can be used to generate electricity by means of nuclear fission.
• In a nuclear reactor, the nuclear fuel is used to carry out sustained fission chain reaction to produce electricity at a controlled rate.

Nuclear fission

Nuclear fission is the process where a heavy atom (uranium or plutonium) is bombarded with neutrons that split the atom to give lighter nuclei.
This process releases tremendous amounts of energy.
Fission of 1 atom of uranium gives 10 million times the energy of combustion of 1 atom of carbon from coal.

ADVANTAGES OF NUCLEAR ENERGY

    •  Alternative source due to depletion of fossil fuels

    •  From small amount of fuel large amount of energy is obtained

DISADVANTAGES OF NUCLEAR ENERGY

• Nuclear waste is hazardous as heavy atoms decay into harmful subatomic particles.
• High setup and maintenance cost
• Limited availability of uranium
• Can be used for destructive purposes

Nuclear fusion

• Fusion means combining lighter nuclei to produce a  heavier nucleus, usually hydrogen or hydrogen isotopes to create helium.

HOME ASSIGNMENT

PAGE 253 Q1,2

PAGE 255  Q3,5,6

Q9 AND Q10 TOMORROW  along with a link to a google form for assessment of this chapter