Unit 1 - Generating Electrical Energy Flashcards
Describe how a biofuel power station generates electricity.
The fuel - wood, straw, plant oil is burned to release heat energy.
The heat energy turns water into steam.
The steam turns a turbine.
The turbine spins a generator.
What parts makes up the national grid?
Step up transformer, pylons and cables, step down transformer.
Describe how a nuclear power station generates electricity.
Uranium or plutonium nuclei split and release energy (nuclear fission).
The energy released turns water into steam.
Steam turns the turbines.
Turbines spin the generator.
Describe how hydroelectric power stations generate electricity.
Water is held in a dam. This them flows down a hill side and as it does it spins a turbine.
This spins a generator to generate electricity.
Describe the energy transfers occurring in a hydroelectric power station.
Gravitational potential energy is transferred to kinetic energy. Kinetic energy is transferred to electrical energy in the generator.
Describe how tidal power stations generate electricity.
Water is moved up a river estuary (mouth) by the gravity of the moon. It gains gravitational potential energy as it is held behind a barrier(barrage).
When released this energy is transferred to kinetic energy, which turns a turbine which in turn spins a generator.
What does a pumped storage system mean for a hydroelectric power station?
Energy can be stored in water in a dam. When demand is low, pumps take energy up to the dam. When there is a surge in demand, water can be released to meet this, generating the electrical energy needed.
What is the advantage of a short start up time? (gas fired power stations have the shortest start up time).
Energy can be generated quickly to meet a surge in demand.
Give 2 advantages of overhead power cables.
They are easy to maintain if a problem occurs.
They are relatively cheap to put up.
They use air to cool the wires.
They use air as an insulator from things around the wires.
They take up little space, do not disturb the land much, can easily go over rivers and motorways.
Give 2 disadvantages of overhead power cables.
They are an eye sore.
They can be affected by severe weather, wind and freezing conditions.
They can be a danger to low flying objects.
What is geothermal energy?
Energy from hot rocks.
Give two advantages and two disadvantages of nuclear power.
Advantages - no carbon dioxide released during production of energy so addition to global warming. Reliable - provides a constant supply of energy.
Disadvantage - produces radioactive waste which is dangerous and difficult to dispose of. Long start up and decommissioning time. Big environmental effect if an accident occurs, releasing radiation.
What are step up transformers used in the national grid?
They increase the voltage of the supply (and decrease the current).
This reduces the amount of wasted heat energy in the wires making the transfer of electrical energy to our homes more efficient.
How can the amount of carbon dioxide produced in burning fossil fuels be reduced without burning less fuels?
Carbon capture and storage. This is where carbon dioxide is trapped in the power station and stored in large spaces like old oil wells under ground or under the sea bed.
Name the fuel used in a nuclear power station.
Uranium or plutonium.
