National & Global Energy Resources (AQA GCSE Physics: Combined Science)

The UK is starting to use wind turbines to generate more of its electrical energy.

Some people think this is a good idea, other people do not.

Suggest reasons why people think that building more wind turbines is a good idea.

It is difficult to store electrical energy that is produced by any kind of power plant.

One solution is a pumped storage dam.

Figure 1 shows a diagram of a pumped storage system.

Figure 1

Read the following passage:

During times of low demand, water is pumped up into the upper reservoir. During times of high demand, sluice gates are opened and water flows down through the generator, producing electrical energy. Pumped storage stations are designed to meet sudden, high demand for electrical energy, such as when thousands of people put their kettle on at half time of a major football game at the same time.

A pumped storage station has a very short start-up time.

Why is it important for the pumped storage station to have a short start-up time?

Figure 2 shows some solar panels on the roof of a house.

Figure 2

The amount of solar energy hitting the solar panels in one day is equal to 700kWh. 

The amount of energy the solar panels generate is 175 kWh.

The kWh is a unit of energy.

A photovoltaic panel generates electrical energy.

Suggest why the government wanted people to use solar power rather than fossil fuels.

The UK government has also made money available to help to build houses that are well insulated.

Describe the features of the walls of a building that cools down very slowly.

A company wishes to build a science park at a coastal location in the UK.

To demonstrate its commitment to sustainability, the company wants to develop a renewable method of powering the buildings.

They are considering three options:

• biofuel
• geothermal power
• wind turbines

Evaluate the use of renewable resources to power the science park.

Representatives from the people who live near the site do not like this idea.

Suggest arguments for both the nuclear company and for the people who live close by.

The company also wishes to use renewable energy for the transport around the science park.

Due to the low amount of energy that batteries can store, battery powered cars need to be very efficient.

State the equation for efficiency.

A typical electric car battery can store 144 MJ of energy before it needs to be recharged.

Using the battery, the car can produce 50 MJ of useful energy before it needs to be recharged.

Calculate the efficiency of the car.

The electrical power demand of the UK is at least  at any given time.

An average gas-fired power station has a power output of .

Determine how many gas-fired power stations are needed to meet the demand of the UK.

The UK only has 32 active gas-fired power stations.

Calculate the shortfall.

A tidal barrage (dam) produces electricity using tides. Figure 1 shows a simplifies diagram of a tidal barrage.

Figure 1

Water flows through the tunnel when the tide goes in or out. The moving water turns the turbine, which produces electricity.

Describe the energy transfers taking place in this system.

The turbine has a cylindrical shape as the turbine spins in a circular path as shown in Figure 1.

The cylinder is 24 m long and has a radius of 5.0 m.

The tide is travelling at 6.0 m/s.

Figure 1

In America, it is estimated that tidal power would cost $150 per MWh produced, whereas coal only costs $60 per MWh produced. 

Some ocean environmental groups oppose the use of tidal power, stating that it can physically harm aquatic life, as well as impacting their ability to communicate. 

One possible short term solution to the global energy crisis is to extract shale gas. Shale gas is natural gas trapped in the rocks underground. This gas can be extracted by a process called fracking. In places where fracking has been done, there is some evidence that it can cause minor earthquakes. Because shale gas is natural gas (methane), it is a fossil fuel.

Another possible solution is to build more nuclear power stations. Nuclear power stations use fission to generate electricity.

Evaluate the two solutions outlined above and give a conclusion.

Name one fuel used in nuclear power stations.

The UK has increased its nuclear power production capacity between 1996 and 1995. But it is now retiring most of these nuclear power plants as shown in Figure 1. New nuclear power plants are in the production and planning stages.

The R. E. Ginna Nuclear Power Plant vaporises 2200 kg of water per hour when operating at full capacity. The water used has an initial temperature of 8.0°C.

Calculate the total power required to vaporise the water used over a period of 24 hours.

You can assume that the power plant is operating at full capacity during this time.

• The specific heat capacity of water is 4200 J/kg°C.
• The latent heat of vaporisation of water is 2 260 000 J/kg.

[6 marks]

Discuss the advantages and disadvantages of nuclear power as an energy resource.