1.2 Generating Electricity

What is a renewable energy resource?

An energy source which can be replenished as it is being used up.

Give 4 examples of renewable energy resources.

1.Wind Energy

2.Hydro-Electricity

3.Tidal Energy

4.Solar Energy

Give an example of non-renewable energy resources.

Fossil fuels

-Coal

-Oil

-Gas

What are the advantages of generating power using gas rather than coal?

1.Flexible generation

-Gas power stations have short start-up times and can be switched on/off readily.

2.Lower emissions of carbon dioxide.

State 2 disadvantages of using renewable energy resources to generate power.

1.Output is determined by external factors e.g. wind speed, so supply is uncertain

2.Generating power through other means is more efficient and economically beneficial.

Explain the environmental impacts of burning fossil fuels.

1.Carbon dioxide contributes to the greenhouse effect and causes global warming.

2.Sulphur dioxide leads to acid rain which causes damage to buildings and crops.

State 3 advantages of fossil fuels as an energy resource.

1.Reliable

2.Can produce large amounts of energy at a given quantity.

3.Cost-effective

State 3 advantages of nuclear power.

1.Very large quantity of energy for relatively small quantity of fuel.

2.Doesn't release greenhouse gases and contribute to climate change.

3.Low fuel costs.

State 3 disadvantages of nuclear power.

1.Produces nuclear waste which is harmful to humans and must be stored safely for centuries.

2.Non-renewable.

3.Risk of nuclear accidents.

Give an example of a social factor which may act as an deterrent for certain types of energy production.

Sound and visual pollution (these are some disadvantages of wind farms).

What is the National Grid?

The National Grid is a network of powerstations, powerlines and transformers that connects and supplies electricity to consumers.

State the two types of transformers.

1. Step-up transformers

2.Step-down transformers

How are step-up transformers used in the National Grid?

They are used when connecting power stations to transmission cables.

They increase voltage (decreasing current).

How are step-down transformers used in the National Grid?

They are used when connecting transmission cables to consumers.

The decrease voltage (increasing current).

Why do transmission lines transfer electricity at high voltages?

1.A high voltage results in a low current

2.The lower the current, the less energy is dissipated as heat.

3.Transport is more efficient this way.

Describe how The National Grid provides a reliable supply of electricity as efficiently as possible.

- Supply and demand is monitored.

- At times of power station failure electricity can be transferred from one part of the Grid to another.

- At times of peak demand, reserve generation can increase supply or electricity can be imported from abroad.

Transformers are used to step-up the voltage before transmission along power lines. This reduces current and power loss as heat in the cables.

State an equation to calculate efficiency.

(useful output energy/ total input energy) x 100

Why does voltage need to be decreased between transmission lines and houses?

1.Lower voltages are safer for domestic use.

2. Household appliances are designed for 230V.