Supply and demand
4 marks · NormalElectricity demand is higher in winter than summer.
State one reason why electricity demand is higher in winter.
Explain how the national grid ensures there is enough electricity to supply everyone during periods of high demand.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
(a) People use more heating and lighting in winter due to shorter, colder days. · must show short and precise cause
(b) The national grid uses a mix of base-load stations (nuclear, fossil fuels) running continuously, and quick-start stations (gas-fired, hydroelectric) to rapidly meet increased demand. They may also import power or use stored energy to cope during peaks. · must show explains strategy using station types, base load and quick start, energy storage
Common mistakes: Not linking grid management to station types or management strategies
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · Gives a valid reason (e.g., heating/lighting required for winter)
B1 (b) · 1 mark · Mentions base-load stations for continuous supply (nuclear/fossil)
B1 (b) · 1 mark · Mentions quick-start stations for coping with peaks (hydroelectric/gas)
B1 (b) · 1 mark · Mentions extra measures such as imports, storage or pre-planned increases
Worked solution
a) People use more heating and electrical devices in winter because it is colder and darker for longer.
b) The national grid meets higher winter demand by using base-load stations that run continuously, and starting up additional stations like hydroelectric or gas turbines rapidly as needed, and by storing and releasing energy.