Energy Resources - Fossil Fuels Flashcards
Why is energy important for agriculture?
- Mechanisation and improved efficiency
- Chemical manufacturing (NPK fertilisers)
- Refrigeration for storage
Why is energy important for industry?
- Machinery
- Chemical reactions (metal ore smelting)
- Crude oil fractional distillation
Why is energy important for domestic uses?
- Space heating in homes
- Lighting
- Appliances
Why is energy important for transport?
- Transport of goods
- Transport of people
How does affluence impact consumption?
Increased affluence leads to increased consumption (may eventually decrease as efficiency improves)
How does climate impact consumption?
- Increased consumption in cold climates for heating
- Increased consumption in warm climates for AC
How does freshwater access impact consumption?
Decreased access increases consumption (desalination is energy intensive)
How does industry type impact consumption?
- Heavy industry increases consumption (steel and mining)
- Service industry decreases consumption
How does population change impact consumption?
Increased population increases overall consumption (not per capita)
What are the three main features of energy resources?
- Abundance
- Intermittency
- Predictability
How is coal formed?
- Decaying OM is compacted over millions of years
- Anaerobic decay
How is oil formed?
- Layers of MMOs are compacted on the seabed over million of years
- Experience high temperature and pressure
How is natural gas formed?
- Same process as oil but experiences higher temperature and pressure
- C bonds are broken and thermogenic methane is formed
What is the difference between thermogenic and biogenic methane?
- Thermogenic - OM breaks down on the seafloor due to high temperature and pressure
- Biogenic - Waste material from MOs eating OM in a reducing environment (anaerobic conditions)
How is coal extracted?
- Deep or open-cast mining
- Drilling and blasting to remove the overlying rock
- Coal removed from seams
How is crude oil extracted?
- Oil wells are drilled
- Oil is brought to the surface using natural pressure or artificial pumping
How is natural gas extracted?
- Steel casing drilled in to the ground
- Gas flows to the surface either naturally or artificially
What are the main uses of coal?
- Power stations
- Steel manufacture
- Cement manufacture
What are the main uses of crude oil?
A range of liquid vehicle fuels
What are the main uses of natural gas?
- Electricity production
- Domestic space heating
What is the energy density of fossil fuels?
High energy density
Why is high energy density useful?
- Produces high temperatures for smelting metal ores and heavy industry use
- Produces high pressure steam which can turn a turbine and produce electricity
What are the environmental impacts of fossil fuels?
- Habitat loss
- Particulates
- Spoil heaps
- AMD
- Oil spills
- Methane leakage (O+G)
What is primary oil recovery?
An oil well is drilled and oil is forced up to the surface using its own pressure
How does primary oil recovery work?
- Natural pressure exists within the reservoir when water is present beneath
- Recovers 20%
What is secondary oil recovery?
The pressure within an oil well is increased artificially
How does secondary oil recovery work?
- Injection water can be pumped in to force oil upwards
- Recovers 20%
What is tertiary oil recovery?
The properties of the oil are artificially changed to reduce its viscosity
How does tertiary oil recovery work?
- Increase temperature
- Add CO2 which dissolves
- Add bacteria
- Add detergent
What is tertiary oil recovery also known as?
Enhanced oil recovery
What is an advantage of enhanced oil recovery?
CO2 injection acts as carbon capture
What are subsea production wells?
Extraction occurs directly on the seabed using floating drilling vessels to which oil and gas can be piped
What is a ROV?
Remotely Operated Vehicle
What is an AUV?
Automated Unmanned Vehicle
What are ROVs and AUVs used for?
- Used in inaccessible and highly pressurised areas
- Carry out remote surveys and sensing
What is the process of hydraulic fracturing?
- Porous and permeable rock is fractured using fracking fluid
- Sand holds the fractures in place to allow ‘tight’ oil and gas to be recovered
What is fracking fluid made up of?
- Water
- Sand
- Chemicals
What are disadvantages of fracking?
- May contaminate groundwater supplies (aquifers)
- CH4 is released
- Water-intensive
What is standard gas recovery?
- Allows gas to move through porous and permeable rock
- 80-90% recovery
What is enhanced gas recovery?
- CO2 or N2 injected to increase the pressure and force the gas upwards
- Recovers remaining 10-20%
What is methane hydrate?
A crystalline solid surrounded by a cage of interlocking water molecules
Where is methane hydrate found?
Areas of high pressure and low temperature
- Permafrost-covered regions
- Deep ocean sediments
How can methane hydrate be extracted?
- Inject CO2 to replace the methane in the structure and release it
- Increase the temperature to reduce the pressure and release the methane
What is coal gasification?
Obtaining gas from coal as it may be applicable to more uses (such as space heating)
What is the product of coal gasification often called?
Syngas
How does coal gasification work?
- Coal is burnt underground in controlled conditions to produce CO2 + H2 + CH4
- H2 and CH4 behave similarly to natural gas
What is coal liquefaction?
Obtaining liquid hydrocarbon from coal as it may be applicable to more uses (such as vehicle fuels)
How does coal liquefaction work?
- Coal converted to a liquid hydrocarbon using solvents
- Syngas converted to a liquid hydrocarbon using chemical processes
What do tar sands and oil shales produce?
Unconventional oil
What are tar sands?
Sands containing bitumous oil, a low quality viscous resource found in sand or sandstone
How is oil extracted from tar sands?
- Sand is excavated and washed with hot water and steam to reduce viscosity
- Oil is recovered and the sand is returned
What are oil shales?
Porous and permeable shale rock containing kerogen
What is kerogen?
A hydrocarbon precursor to oil and gas (therefore being low quality)
How is oil extracted from oil shales?
- Shale is mined and heated at 750C
- Pyrolysis occurs and the viscosity of the kerogen is reduced to allow for collection
