P3 Specification

Module P3: Sustainable Energy

P3.1 How much energy do we use?

1. understand that the demand for energy is continually increasing and that this raises issues

about the availability of energy sources and the environmental effects of using these sources

2. recall the main primary energy sources that humans use: fossil fuels (oil, gas, coal), nuclear

fuels, biofuels, wind, waves, and radiation from the Sun

3. understand why electricity is called a secondary energy source

4. understand that power stations which burn fossil fuels produce carbon dioxide which

contributes to global warming and climate change

5. understand that when electric current passes through a component (or device), energy is

transferred from the power supply to the component and/or to the environment

6. recall that the power (in watts, W) of an appliance or device is a measure of the amount of

energy it transfers each second, ie the rate at which it transfers energy

7. use the following equation to calculate the amount of energy transferred in a process, in joules

and in kilowatt hours:

energy transferred = power × time

(joules, J)            (watts, W)           (seconds, s)

OR

(kilowatt hours, kWh) (kilowatts, kW) (hours, h)

8. use the following equation to calculate the rate at which an electrical device transfers energy:

power = voltage × current

(watts, W) (volts, V) (amperes, A)

9. understand that a joule is a very small amount of energy, so a domestic electricity meter

measures the energy transfer in kilowatt hours

10. calculate the cost of energy supplied by electricity given the power, the time and the cost per

kilowatt hour

11. interpret and process data on energy use, presented in a variety of ways

12. interpret and construct Sankey diagrams to show understanding that energy is conserved

13. use the following equation in the context of electrical appliances and power stations:

efficiency =  energy usually transferred                 × 100%

total energy supplied

Candidates will be expected to consider / calculate efficiency as a decimal ratio and as a

percentage

14. suggest examples of ways to reduce energy usage in personal and national contexts.

P3.2 How can electricity be generated?

1. understand that electricity is convenient because it is easily transmitted over distances and can

be used in many ways

2. recall that mains electricity is produced by generators

3. understand that generators produce a voltage across a coil of wire by spinning a magnet near

it

4. understand that the bigger the current supplied by a generator, the more primary fuel it uses

every second

5. understand that in many power stations a primary energy source is used to heat water; the

steam produced drives a turbine which is coupled to an electrical generator

6. label a block diagram showing the basic components and structures of hydroelectric, nuclear

and other thermal power stations

7. understand that nuclear power stations produce radioactive waste

8. understand that radioactive waste emits ionising radiation

9. understand that with increased exposure to ionising radiation, damage to living cells increases

eventually leading to cancer or cell death

10. understand the distinction between contamination and irradiation by a radioactive material, and

explain why contamination by a radioactive material is more dangerous than a short period of

irradiation from the radioactive material

11. understand that many renewable sources of energy drive the turbine directly eg hydroelectric,

wave and wind

12. interpret a Sankey diagram for electricity generation and distribution that includes information

on the efficiency of energy transfers

13. recall that the mains supply voltage to our homes is 230 volts

14. understand that electricity is distributed through the National Grid at high voltages to reduce

energy losses.

P3.3 Which energy sources should we choose?

1. discuss both qualitatively and quantitatively (based on given data where appropriate), the

effectiveness of different choices in reducing energy demands in:

a. domestic contexts

b. work place contexts

c. national contexts

2. understand that the choice of energy source for a given situation depends upon a number of

factors including:

a. environmental impact

b. economics

c. waste produced

d. carbon dioxide emissions

3. describe advantages and disadvantages of different energy sources, including

non-renewable energy sources such as:

a. fossil fuels

b. nuclear

and renewable energy sources such as:

c. biofuel

d. solar

e. wind

f. water (waves, tides, hydroelectricity)

g. geothermal

4. interpret and evaluate information about different energy sources for generating electricity,

considering:

a. efficiency

b. economic costs

c. environmental impact

d. power output and lifetime.

5. understand that to ensure a security of electricity supply nationally, we need a mix of

energy sources.

© OCR 2011 GCSE Science A