P1.4 Methods we use to Generate Electricity Flashcards
What are examples of non-renewable energy resources? (4)
The 3 fossil fuels: coal, natural gas and Oil, and Nuclear fuels like uranium and plutonium
What are issues with non-renewable sources of energy?
They will run out one day, they all do damage to the environment due to their emissions or with their mining and storage, but they are currently our main source of energy
What are examples of renewable sources of energy? (7)
Wind, tides, solar, biofuel, waves, hydroelectric and geothermal
What are the benefits of renewable sources of energy?
They will never run out, and although they do damage to the environment, it’s not as bad as non-renewables
What are the drawbacks of renewable sources of energy?
They don’t provide much energy and some of them are unreliable as they depend on weather
How do power stations supply produce electrical energy from fossil fuels? (4 steps)
- The fossil fuel is burnt converting its stored chemical energy into heat energy
- The heat energy is used to boil water to produce steam
- The steam turns a turbine, converting heat energy into kinetic energy
- The turbine is connected to a generator, which transfers kinetic energy into electrical energy
How is electricity produced from nuclear sources of energy?
It’s the same as the fossil fuel power stations, but energy is released from nuclear fission - nuclear power stations take the longest to start up
How is electricity generated from wind?
Similar to the turbines connected to a generator in a fossil fuel generator - The blades from a windmill are turned by wind which turns a generator, converting kinetic energy into electrical energy
What are the advantages of using wind energy? (1)
It produces no atmospheric pollution - apart from a little when the windmills are manufactured
What are the disadvantages of using wind energy?
Visual pollution - they spoil the landscape (but they can be removed leaving the scenery unharmed), noise pollution - they are very loud, and they do not produce power when there is no wind
How many windmills do you need to replace one coal-fired power station?
1500
How do solar cells produce electricity?
They produce electricity directly from the sun’s radiation
What are the benefits of using solar cells to produce electricity? (3)
No atmospheric pollution (a part from some when being manufactured), a very reliable source of energy is sunny countries and they are very expensive to buy but free running costs means it is cost-effective
What are the drawbacks of using solar cells to generate electricity? (3)
Can only produce electricity in the daytime, can only be used to generate electricity on a small scale and connecting them to the national grid would be too expensive
What has to be done in order to generate electricity from hydroelectric power?
The flooding of a valley bay building a big dam - rainwater is caught and allowed out through turbines
What are the advantages of using hydroelectric power stations? (4)
There is no atmospheric pollution, they are an immediate response to an increased demand for electricity, reliable (unless there is a draught), and although it’s initial costs are high, there’s no fuel and minimal running costs so it’s cost effective
What are disadvantages of using hydroelectric power stations? (4)
There’s a big impact on environment due to flooding of a valley, which causes vegetation to rot releasing methane and CO2*, destroys habitats and the reservoir looks ugly when it dries up
What is the need for pumped storage?
To store energy which has been generated at times of low demand e.g. at night, but can be used at times when there is high demand of electricity e.g. when Mia Khalifa releases a new vid
How is excess power used in a hydroelectric power station?
A pumped storage pumps water from a lower reservoir to an upper reservoir
What are tidal barrages?
Big dams built across river estuaries, with turbines in them which are connected to generators
What source of energy is in tidal barrages?
The gravity of the sun and moon, as this is what causes tides
What are the advantages of using tidal barrages? (5)
It causes no atmospheric pollution, the tides are reliable, store energy for when there is a high demand of electricity, they have the potential to generate a lot of energy, and although they have high initial costs, they have low running costs and don’t need fuel so they are cost effective
What are the disadvantages of using tidal barrages? (5)
Prevent access for boats to pass, spoils the view, alters the habitats of wildlife, the tide size is unpredictable and they don’t work when the water level is the same on either side of the barrage
How do you generate electricity using waves?
Lots of small wave-powered turbines are located around the coast - as the waves come in to the shore, they provide an up and down motion which can be used to drive a generator
What are the advantages of using waves to generate electricity? (2)
No atmospheric pollution, and they have a high initial cost but they don’t require fuel and have minimal running costs
What are the disadvantages of using waves to generate electricity? (4)
Spoils the view, hazardous to boats, unreliable, and they can only provide electricity on a small scale
What is geothermal energy?
Using heat energy from hot underground rocks to generate electricity
Where can geothermal energy be used?
In volcanic areas where hot rocks lie near the surface
Where does the heat from the rocks come from (in geothermal energy)
From radioactive elements (e.g. uranium) deep inside the Earth
How is geothermal energy used to generate electricity?
Steam and hot water rises to the surface and are used to drive a turbine, which is connected to a generator
What are the benefits of geothermal energy? (2)
It’s free energy with no real environmental problems
What are the drawbacks of geothermal energy? (2)
There aren’t many suitable locations for power stations and the cost of building a power station is often high compared to the amount of energy we can get out of it
What are biofuels?
Renewable energy sources
What are biofuels made of?
Plants and waste
How are biofuels used to generate electricity?
In the same way as fossil fuels
What are the main benefits of biofuels? (2)
They are renewable and carbon neutral
What do the gases produced from burning fossil fuels do to the environment? (2)
The carbon dioxide released into the atmosphere adds to the greenhouse effect and coal and oil release sulphur dioxide when burnt which adds to acid rain
How do fossil fuels affect habitats and landscapes? (2)
Coal mining makes a mess of landscapes and oil spillage can cause serious environmental problems affecting animals which live in and around the sea
What are the benefits of nuclear fuel? (3)
It’s clean so it doesn’t release any harmful gases, it produces a lot of energy and nuclear fuel is relatively cheap
What are the drawbacks of nuclear fuel? (3)
The nuclear waste produced is very dangerous and difficult to dispose of, the overall cost of nuclear power is high due to the cost of the power station and decommissioning (the shutting down of power stations so it’s completely safe), and there is always a risk of equipment failure like Chernobyl
What are the drawbacks of biofuels? (3)
The production produces methane, large areas of forest have been cleared out for biofuel farms (which destroys habitats and the burning and decay of forests releases carbon dioxide and methane) and there is a limit to the available space for faming biofuels
What is Carbon capture storage used for?
To reduce the amount of carbon dioxide building up in the atmosphere
How does Carbon capture storage work?
The carbon dioxide produced by burning fuels is captured and stored underground so it cannot add to global warming
What factors are needed to be considered when setting up a power station? (5)
How much it costs to set up and run, how long it takes to build, how much power it can generate, how it affects the environment and decommissioning time
What is meant by start-up costs?
How much money is need to build the power station - bigger power stations need more money to build
Why does reliability need to be considered when building a power station?
Because there is constant demand for electricity - so energy sources which depend on weather can be unreliable
What energy sources have lower running and fuel costs?
Renewables - they have the lowest running costs as there’s no actual fuel involved
Where does a solar power station need to be located?
Anywhere, the sunnier the better
Where does a gas power station need to be located?
Anywhere, where there’s piper gas
Where does a hydroelectric power station need to be located?
In hilly, rainy places with floodable valleys
Where does a wind power station need to be located?
In exposed, windy places like moors and coasts or out at sea
Where does a oil power station need to be located?
Near the coast - oil is transported by sea
Where does a waves power station need to be located?
On the coast
Where does a coal power station need to be located?
Near coal mines
Where does a nuclear power station need to be located?
Away from people in case of disaster and near water for cooling
Where does a tidal power station need to be located?
Big river estuaries where a dam can be built
Where does a geothermal power station need to be located?
In volcanic areas where hot rocks are near the Earth’s surface - which is fairly limited
What is atmospheric pollution caused by?
The burning of fossil fuels and biofuels - and other fuels which involve the transportation of fuels via lorries fuelled by fossil fuels
What sources of energy are using up resources?
Non renewables, e.g. fossil fuels, not only are they running out, but they damage resources around the mining of them
What causes visual pollution?
You could argue that all sources of energy cause visual pollution
What causes noise pollution?
Anything that involves turning a turbine
What causes the disruption of habitats? (3)
Hydroelectric dams, tidal barrages and the growing of biofuels
What cause the disruption of leisure activities?
Boats can be disrupted by tidal barrages or offshore wind farms
What will happen to the demand of electricity in the future?
It will increase
How will an increase in the demand of power from people affect the amount of power stations and pollution?
It will increase
How will people decrease the demand of electricity?
Either by using energy-efficient appliances and/or being more careful not to waste energy in the home e.g. turning off appliance when not in use
How does electrical energy get into homes and industry?
The National Grid takes electrical energy to where it’s needed
What is the National Grid?
A network of pylons and cables that covers the whole of Britain
How can you transmit such a huge amount of power in the National Grid? (2)
To transmit such a huge amount of power, you either need a high voltage or a high current
Out of the two ways of transmitting such a huge amount of power in the National Grid, which one is used? And why?
The voltage is increased - this is because increasing the current loses loads of energy through heat in the cables
What is a transformer?
A device used to change the voltage of a current supply
Why are small wires used in National Grid?
Because it is cheaper than using big pylons with huge insulators
What are the two forms of transformers?
Step-up transformers and step-down transformers
What do step-up and step-down transformers do in the National Grid?
To begin with, the voltage is stepped-up for efficient transmission, but it is then stepped down to use safely in homes
Why are underground cables more expensive than overhead cables?
Because overhead cables are cooled down by the air surrounding them, whereas underground cables need a cooling system which makes them more difficult and expensive
Why are overhead cables thinner than underground cables?
Because air acts as an electrical insulator so they don’t need any electrical insulation whereas underground require a thick layer of insulation to stop electrical energy being lost
How difficult is it to maintain and install overhead and underground cables?
Overhead cables are cheaper and easier to install, but are very vulnerable to bad weather conditions - underground cables are hard to maintain as they are underground
What hazards are there with overhead cables?
They’re more exposed and aren’t insulated which means people are at risk of getting a fatal electric shock, and overhead cables can be hazardous to low-flying aircrafts
What environmental problems are there with overhead cables and electricity pylons?
They cause visual pollution as they’re an eye sore
What environmental problems are there with underground cables?
You have to dig up land to install underground cables which disrupts the land and can destroy habitats
What land restrictions are there with underground cables? Is this the same for overhead cables?
Underground cables means you can’t use the land around the cables e.g. for building foundations - you can use the land around overhead cables as long as it doesn’t get in the way of the pylons
