The frequently asked questions related to this topic are: what is renewable energy? the examples of Renewable and non-renewable energy and the advantages of using renewable energy.

Renewable energy sources are the energy sources which can be continuously replaced. Examples of renewable energy are:

1. Hydro energy
2. Solar energy
3. Wind energy
4. Geothermal energy
5. Biomass
6. Tidal energy

Advantages of Using Renewable Energy
1. Clean and do not pollute the environment.
2. Easily obtain.
3. Can be replenished once it has been used.
4. Can prevent energy crisis.

Hydroelectric

Advantages

1. It is a renewable energy.
2. Building a dam does not pollute the environment.
3. In a lot of country, water can be easily obtained and is free.
4. Building a hydroelectric plant does not involve very high technology as nuclear power plant.

Disadvantages

1. Building a dam will cause a large area flooded with water, and hence seriously destroys the ecosystem nearby.
2. The flooded area causes the loss of wild life habitat and agriculture land.
3. Dam failure happens will cause a disaster to the lower reaches area of the river.
4. The cost to build a dam is very high.

Fossil Fuel.

Advantages

1. It is relatively easy to be collected as they are present in large amount in one place.
2. It contains high energy capacity.

Disadvantages

1. It releases a lot carbon dioxide when it is burned. Large amount of carbon dioxide presence in the atmosphere will cause the increase of the temperature of the atmosphere, known as global warming. Global warming is the most serious environmental problem that we are facing now.
2. Fossil fuels are non-renewable energy.
3. Pollute the air. Burning of fossil fuel will release particles and some hazardous gases such as sulphur dioxide and nitrogen dioxide which will pollute the air.

Solar Power

Advantages

1. It is a renewable energy.
2. Sunlight is free and can be obtained easily.
3. It does not pollute the air.

Disadvantages

1. A large area is needed to install the solar plate.
2. The amount of sunlight at non-tropical area depends on the season.
3. The energy collected need to be store in a cell so that it can be used at the time sunlight is not present.
4. Its capacity is limited by the capacity of the cell. Normally a cell has relatively low capacity.

Nuclear Power

Advantages:

1. The nuclear fuel such as uranium and plutonium has high energy capacity. Small amount of uranium can produces huge amount of energy.
2. Nuclear energy does not pollute the air.

Disadvantages

1. Hazardous radioactive waste is produced during nuclear reaction.
2. The radioactive waste will cause pollution in a very large area if leakage happens in the nuclear power plan.
3. The cost to maintain a nuclear plant is very high.
4. Building a nuclear plant involving very high technology. Only a few countries own such technology.

Biomass

1. Biomass is biological material derived from living organisms such as wood and animal waste.
2. As a renewable energy source, biomass can either be used directly via combustion to produce heat, or indirectly after converting it to various forms of biofuel.
3. Heat energy produced from the burning of biomass can be used to generate electricity.

Advantages

Disadvantages

Wind Power

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Advantages

1. It is a renewable energy.
2. It does not pollute the environment.
3. It is suitable for mountain area because the wind speed in mountain area is relatively high.

Disadvantages

1. A large area is needed to build the windmills.
2. The windmills will produce high level of noise.
3. The power generated is inconsistent due to the inconsistent of the wind speed and wind direction.

 

A national Grid Network is a network of cable that connects all the power stations in a country to transmit electricity to the consumers throughout the nation.

The advantages of the National Grid Network

1. Reduces power lost during transmission. The potential difference is increased before transmission. This can reduce the current and hence reduces the energy lost during transmission.
2. Electricity supply is more stable and reliable. This ensures a continuous supply of electrical energy to the whole country.
3. Electric current can be distributed to different users according to the voltage requirement. Transformer is used to step down the voltage to certain level according to the needs of the consumers.
4. Maintenance and repair work can be done at anytime. This is because any power stations can be shut down without affecting users in other areas.

 

 

Problems Involving Electricity Transmission.

1. Power Loss During Transmission. 
2. The high voltage transmission cable is very dangerous. 
3. The cost of the cables are high. 
4. Charge leakage may happen between cables and earth. 
5. Pylons may be struck by lightning. 
6. Pylons and cables may be struck by light aircraft.

 

1. The heating effect of current in a coil.

Power is lost as heat I₂R whereby I is the current flowing through the coil and R is the resistance of the coil

Methods to increase the efficiency
Use thick copper wires of low resistance. Use coolant to decrease the temperature of the transformer.

2. Heating effect of induced eddy currents

In the iron core. When the magnetic field in the iron core fluctuates, eddy currents are generated in the iron core.

Methods to increase the efficiency
Use a laminated iron core whereby each layer is insulated with enamel paint to prevent the flow of eddy currents. The high resistance between layers of the iron core decrease the prevalence of eddy currents and heat.

3. Magnetization of the Iron Core.

The energy used in the magnetization and de-magnetization of the iron core each time current changes its direction is known as hysterisis. This energy is lost as heat which subsequently heats up the iron core.

Methods to increase the efficiency
Use a soft iron core that is easily magnetized and de-magnetized.

4. Flux leakage.

Some of the induced magnetic flux from the primary coil is not transmitted to the secondary coil, therefore the e.m.f in the secondary coil is decreased.
The secondary coil(windings) are intertwined tightly with the primary coils. The iron core should form a closed loop.

Methods to increase the efficiency
The secondary coil (windings) is intertwined tightly with the primary coils. The iron core should form a closed loop.

 

Calculation of Current Change

Ideal Transformer

Non-ideal transformer

V_p = input (primary) potential difference
V_s = output (secondary) potential difference
I_p = input (primary) current
I_s = output (secondary) current

 

 

There are 2 types of transformer, namely

1. the step up transformer
2. the step down transformer

Step-up Transformer

1. A step-up transformer is one where the e.m.f. in the secondary coil is greater than the e.m.f. in the primary coil. It is used to increases the potential difference.
2. The number of windings in the secondary winding is greater than the number of windings in the primary coil.
3. The current in the primary coil is greater than the current in the secondary coil.