P1.4 Generating Electricty Flashcards
How is electricity produced in power stations?
Water is heated to produce steam. The steams drives the turbine which is coupled with an electrical generator that produces electricity.
Name the fossil fuels
Coal
Oil
Gas
What’s a pro of a gas-fired power station?
Hot gases drive the turbine directly which is quicker
What’s a biofuel?
any fuel obtained from living or recently living organisms. Some biofuels can be used in small scale, gas fired power stations. They’re renewable sources of energy.
What fuel is used in a nuclear power station?
Uranium or sometime plutonium
How is energy produced in a nuclear power station?
Nuclear fission
Lots of uranium nuclei so lots of fission reactions take place, releasing lots of energy
How do we use energy from wind?
Wind drives turbines
Wind makes them rotate and drive the generator
How do we use water to generate electricity?
Falling water, waves or tides can be used.
In a hydroelectric power station water is collected in a reservoir and the water flows downhill which turns turbines at the bottom of the hill. The water is pumped back to the top when the demand for electricity is low.
Waves and tides drive turbines too
What’s solar energy?
From the sun, travels through space to the earth as electromagnetic radiation.
Solar cells transfer the energy into electricity and lots of these make a solar panel.
A solar power tower uses thousands of mirrors to reflect sunlight onto a water tank to heat the water and produce steam.
What’s geothermal energy?
Produced inside the earth by radioactive processes and this heats the surrounding rock. In volcanic areas, very deep holes are drilled and cold water is pumped down to the hot rocks. It’s heated and comes back to the surface as steam. The steam drives turbines which drive generators, producing electricity.
What does non-renewable mean?
It’s eventually going to run out
Eg. Fossil fuels
What does sulphur dioxide produce?
Acid rain
What are the advantages of coal, oil, gas and nuclear energy?
Coal- bigger reserves and reliable
Oil- reliable
Gas-reliable
Nuclear- doesn’t make polluting gases and reliable
What are the advantages of getting energy from water, wind, solar and geothermal energy?
Renewable
No production of polluting gases
Free energy resource
Some are reliable
What are the disadvantages of using fossil fuels to produce electricity?
Non-renewable
Produces carbon dioxide - greenhouse gas causes global warming
Produces sulphur dioxide - causes acid rain
What’s a disadvantage of using nuclear energy to produce electricity?
Non-renewable
Produces hazardous nuclear wastes, which is difficult to dispose of safely
Small risk of a big nuclear accident
What’s the national grid?
A network of cables and transformers that connects power stations to buildings. Our whole country is connected to the network.
What’s the national grid’s voltage?
132,000 V or more
What voltage do power stations produce?
25,000 V
What, in the national grid, changes the voltage before it goes to your home?
Step-down transformers reduce the voltage to 230 V for homes
What makes the voltage increase in the national grid for the electricity to travel through the cables?
Step-up transformers
Voltage increases to go through the cables because it reduces the energy wasted, making it more efficient
What’s a base load demand?
A constant amount of electricity is provided by nuclear, coal-fired and oil-fired power stations
What is start-up time?
The time it takes for a particular energy to start producing electricity
What energy resource has the shortest start up time?
Gas
What energy source has the longest start-up time?
Nuclear
What are the energy transfers in a power station?
Chemical -> thermal -> kinetic -> electrical
What’s TV pickup?
It’s an increase in demand for electricity depending what’s on tv, eg. Adverts
If demand is not met, there will be a power cut.
What’s decommission?
Nuclear power stations are expensive to build and decommission. It takes as long to build as it would to take down. This increases the price of electricity produced.
What’s are the pros and cons of underground cables?
Cons - more difficult to repair, expensive
Pros - can’t see them
What are the pros and cons of overhead cabling?
Pros - cheaper, easier to repair and works well
Cons - dangerous to clean, looks ugly, damaged by storms
