Renewable Energy Sources Flashcards
Wind power involves putting lots of [ ] (turbines) up in [ ] like on [ ] or around coasts
windmills
exposed places
moors
How to wind turbines work?
Each wind turbine has its generator inside it. The electricity is generated directly from the wind turning the blades, which turns the generator
What are the advantages of wind turbines?
No pollution (except for when they are manufactured)
No fuel costs and minimal running costs
No permanent damage to the landscape
How many wind turbines do you need to replace a coal power station?
About 1500
What are the disadvantage of wind turbines?
Spoil the scenery - eye sore Very noisy - noise pollution No power when the wind stops Almost impossible to increase supply when there's extra demand Initial costs are quite high
How to solar cells work?
They generate electric currents directly from sunlight.
Where is solar power used?
1) Remote places (Australia)
2) For calculators/watches - don’t need much energy
3) Power road signs and satellites
4) Generate electricity on a small scale (individual homes)
What are the advantages of solar power?
No pollution (except for when they are manufactured)
In sunny countries it is very reliable
The energy is free and running costs are low
What are the disadvantages of solar power?
Only work in day time
often not practical or too expensive to link up to national grid
High initial costs
What does hydroelectric power require?
The flooding of a valley to build a big dam
We turn the water’s [ ] energy into [ ] energy
Kinetic
electrical
hydroelectric power: [ ] is caught and allowed through [ ]
Rainwater
turbines
Why does hydroelectric power impact the environment?
Flooding of the valley cause vegetation to rot (which release methane and CO2)
Possible loss of habitats
Reservoir can be unsightly when it has dried up
What are the advantages of hydroelectric power?
It can provide an immediate response to an increase demand for electricity
No problem with reliability (except in drought)
No fuel, minimal running costs
Generate energy on a small scale or in remote areas
What are the disadvantages of hydroelectric power?
Initial costs are high
Impact on the environment
Why is their a need to store energy? How can we store energy?
Large power stations have huge boilers which have to be kept running all night even though the demand is very low therefore there is a surplus of electricity.
We can store energy in pumped storage
How does pumped storage work?
When there is a surplus of electricity, electricity is used to pump water from a lower reservoir to a higher reservoir. This can be released quickly during periods of peak demand.
How does wave power work?
You need lots of small wave-powered turbines around the coast.
As waves come in to the shore they provide an up and down motion which can be used to drive a generator.
What are the disadvantages of wave power?
Spoils the view Hazardous to boats Fairly unreliable (not so many waves when there's no wind) Initial costs are high Never going to be large scale
What are the advantages of wave power?
No pollution
No fuel costs and minimal running costs
Very useful on small islands
What are tidal barrages?
Big dams built across river estuaries, with turbines in them
How do tidal barrages work?
As the tide comes in it fills up the estuary to a height of several meters - it also drives the turbines. The water can then be allowed out through the turbines at a controlled speed.
What is the source of energy for tidal barrages?
The gravity of the sun and the moon
What are the advantages of tidal barrages?
No pollution
Pretty reliable (twice a day without fail)
Always near to the predicted height
Excellent for storing energy ready for periods of high demand
No fuel costs and minimal running costs
Could generate a significant amount of energy
What are the disadvantages of tidal barrages?
Preventing free access by boats Spoiling the view Altering the habitat of the wildlife The height of the tide is variable - lower 'neap' tides provide significantly less energy than 'spring' tides Moderately high initial costs
Where is geothermal energy possible? Where does the heat come from?
In volcanic areas where hot rocks lie quite near the surface. The source of much of the heat is the slow decay of various radioactive elements, including uranium, deep inside the earth.
How does geothermal energy work?
Cold water is pumped down to the hot rocks (about 7 km down) Steam and hot water rise to the surface and are used to drive a turbine which drives a generator.
What are the disadvantages of geothermal energy?
Are’t many suitable locations for power plants
High costs compared with out much energy we get out of it
What are the advantages of geothermal energy?
Can be used to heat buildings directly
Brilliant free energy
No real environmental problems
What are biofuels made from?
Plants and watse
Biofuels are [ ] energy resources. They’re used to generate [ ] in the same way as [ ] - they’re burnt to [ ].
renewable
electricity
fossil fuels
heat up water
What else can biofuels be used in?
Cars - like fossil fuels
What are sludge digesters used in?
Sewage processing
What is the state (solid/liquid/gas) of biofuels?
solid or liquid or gas
eg, straw, ethanol, methane
Where can we get biofuels from?
From organisms that are still alive or from dead organic matter - like fossil fuels, but from organisms that have been living much more recently.
Biofuels: Crops like [ ] can be [ ] to produce ethanol
Plant oils can be [ ] to produce [ ]
sugar cane
fermented
modified
biodiesel
What’s the main advantage of biofuels in cars?
They don’t produce as much greenhouse gas compared with petrol and diesel
