Energy Flashcards
What is primary energy?
Energy that is released as a direct source e.g- Coal
What is secondary energy?
Energy that is released when primary energy is converted from one form to another. eg.-Electricity
What are some examples of primary energy?
Crude Oil
Natural Gas
Nuclear Energy
Waste
Biomass
Hydroelectricity
Wind
Tidal
What are some examples of secondary energy?
Petroleum Products
Manufactured Solid Fuels
Electricity
Heat/Thermal Energy
Biofuels
What is a renewable energy resource?
A resource that can be replenished at a similar rate to which it is being used up
They are also known as FLOW resources as there is constant energy transfer occuring which will be balanced if it is to be sustainable
What are some examples of truly renewable resources?
Tidal, wind and solar power as they can’t be used up
What is a non-renewable energy resource?
Energy that will run out and can’t be replaced in the forseeable future
Known as STOCK resources as they are finite and when used they will be gone forever
What are some examples of non-renewable resources?
Fossil fuels (coal, oil & natural gas), nuclear energy
Whether a resource is renewable or not depends on what?
The rate at which it is being utilized compared to the rate at which it is being replenished. If these rates are similar then the resource is deemed renewable
Why does wood need to be carefully managed?
If wood reserves are used up too quickly in a short space of time then the cycle of replenishment is disrupted and the resource is gone.
However if the resource is managed to make sure it will have time to be replaced then it is renewable.
Why does geothermal energy need to be carefully managed?
If the power station is too large for the site and is continually pumping water into the ground then the ground may eventually begin to cool also. Therefore the resource may be lost.
What are fossil fuels?
They are hydrocarbon deposits that are derived from living matter from previous geological times. Coal, oil and natural gas are examples
Why are fossil fuels considered non-renewable eventhough they can be replaced?
It is because the rate at which we are using them is greater that the rate that they can be replenished (millions of years) which is not the forseeable future
How is coal formed?
It was formed during the carboniferous times where forests growing in swamps died and was covered in layers of sediment. Over time the organic material doen’t decompose and so it is preserved. Layers of rock form on top of the material and causes immense pressure which squeezes out the moisture. The coal is left behind between the layers of sandstone and shale.
How is coal extracted?
If it is buried deep underground then shaft mines will be dug out
If it is close to the surface then the over burden will be cleared in order to do open cast mining. Machines will quarry out the coal until there is no more. The overburden will eventually be replaced and the ground restored.
How is coal used to produce electricity?
The coal is burnt in a furnace which creates thermal energy. This is used to create steam which turn a turbine and in turn turns a generator. This produces electricity which goes through a transformer that changes the voltage.
What are the advantages of coal?
- Cost effective in power stations
- The most abundant fossil fuel
- Generates large amounts of energy
- Easy to find
- Reduces dependance on the use of oil
What are the disadvantages of coal?
- Mining is difficult and could endanger the lives of miners
- Prduces CO2 when burnt
- Produces sulphur dioxide which contributes to acid rain
- Destroys vast areas of land
- Requires extensive transportation
How is oil formed?
Millions of years ago microscopic sea creatures that died were covered with sediment. This meant that they were trapped between these layers which compressed them. This created huge amounts of pressure which turned the organic material to oil.
The oil then percolated through the pores in the rock and travelled upwards. If the oil was trapped in impermeable rock then an oil reservoir would be formed
How is oil extracted?
Drills are used that penitrate the layers of silt/ sand in order to reach the rock and obtain the oil
How is oil used to generate electricity?
The oil is burnt in a furnace which creates steam and the steam turns a turbine which turns a generator and produces electricity.
What are the advantages of oil?
- Easy to transport
- Generates huge amounts of energy
- Cleaner and easier to burn than coal
- Easy to find
What are the disadvantages of oil?
- Causes environmental hazards (oil spills)
- Produces sulphur dioxide and trioxide which lead to acid rain
- Not as efficient as natural gas
- Products may be toxic
How is natural gas formed?
Natural gas is formed at the same time as oil. Like oil it is formed when micro-organisms die and get covered in layers of sediment. Pressure builds which results in heat and the gas if formed. Usually it it stored in the upper parts of an oil reservoir
How is natural gas extracted?
Wells are created using drills that go down into the reservoir. The gas is then forced out by its own pressure until it drops significantly. At this point pressurised fluid is used to pump it up. The area where the gas was is then replaced by mud
How is natural gas used to produce electricity?
Natural gas is pumped into the gas turbine, where it is mixed with air and burnt creating heat. As well as heat, burning natural gas produces a mixture of gases called the combustion gas. The heat makes the combustion gas expand. In the enclosed gas turbine, this causes a build-up of pressure. The pressure drives the combustion gas over the blades of the gas turbine, causing it to turn. This also spins the generator which produces electricity.
What are the advantages of natural gas?
- Non toxic
- Very efficient
- Produces 70% less carbon dioxide than other fossil fuels
- Inexpensive
- Generates large amounts of energy
What are the disadvantages of natural gas?
- Unplesant odurs
- Problems with transportation
- Leaks can be difficult to spot
- Can produce some sulphur dioxide
What is an energy mix?
The different sources of energy used by households, industry and commerce, and in the electricity generation industry
Why do energy mixes change?
- Advance in technology- easier to extract some sources
- Fossil fuels will deplete as they are a finite/ non renewable resource
- Nuclear energy will make up for the lost fossil fuel energy
What is acid rain?
A type of air pollution that is caused when fossil fuels (coal and oil) are burnt which releases sulphur dioxide and nitrogen dioxide into the air
How does acid rain form?
- Combustion of fossil fuels
- Acidic gases (sulphur dioxide and nitrogen dioxide) are released into the atmosphere
- The gases are carries by the prevailing wind
- The gases disolve into the rainwater and forms acidic rain (sulphuric acid)
What are the effects of acid rain on trees?
- Damages leaves
- Reduces ability to photosynthesise which limits the energy and nutrients they can take in
- They are exposed to toxic substances which are slowly released into the soil