Fossil Fuels Overview | AQA A-Level Environmental Science Revision | Primrose Kitten

Fossil fuels

Fuels made from decomposed remains of dead organisms like coal, oil, and natural gas

Coal formation

Terrestrial plant decomposition in anoxic conditions forming dead organic matter converted to coal

Coal properties

Non-renewable, high energy density, chemical energy stored in bonds, depletable, high abundance

Coal extraction

Location found through seismic surveys, IR spectroscopy, resistivity; trial drilling for viability

Mining viability factors

Cutoff grade, overburden depth, workforce availability, land conflicts, deposit location

Mining methods

Open-cast for thin surface deposits, underground for deeper ones like long wall mining

Open-cast vs. underground mining

Open cast causes more habitat destruction, underground may be lower risk due to no deep excavation

Environmental impacts of mining

Noise pollution, dust pollution, spoil heaps, acid mine drainage, turbid drainage water

Reducing mining impacts

Baffle mounds for noise, water sprays for dust, planting trees for spoil heaps, adding limestone for acid drainage, sedimentation pool for turbid water

Coal combustion impacts

Release of greenhouse gases absorbing infrared radiation, causing warming

Greenhouse Gases

Absorb infrared radiation, causing warming in the troposphere.

Flue-Gas Desulphurisation

Process to remove sulphur dioxide from combustion gases.

Acid Rain

Formed by sulphur dioxide mixing with water in the atmosphere.

Coal Gasification

Process to convert coal into syngas mixture for various uses.

Syngas

Mixture of hydrogen, carbon monoxide, and methane from coal.

Coal Liquefaction

Conversion of coal into liquid fuel, releasing carbon dioxide.

Smokeless Coal

Coal treated to remove volatiles, reducing environmental impacts.

Oil Formation

Originates from decomposed marine plankton in sedimentary rock.

Reservoir Rock

Porous and permeable rock storing oil, capped to prevent migration.

Fractional Distillation

Process to separate components of crude oil like petrol.

Primary Oil Recovery

Natural pressure release causing oil flow to the surface.

Secondary Oil Recovery

Artificial pressure increase using CO2 or water for more oil recovery.

Seismic Surveys

Method to locate oil deposits using sound waves.

Trial Drilling

Collecting physical samples after locating oil deposits.

Oil Recovery Challenges

Difficulties due to depth, viscosity, impermeability, and profitability.

Environmental Impacts of Oil

Considered before and after use, affecting ecosystems and climate.

Oil pollution

Caused by shipping accidents, pipeline leaks; blocks light penetration, reduces oxygen levels

Marine seismic surveys

Create noise pollution disrupting dolphin and whale communications

Habitat damage

Resulting from pipeline and oil rig construction e.g. coral reef destruction

Wastewater discharge

From washing oil tanks on carriers releases toxins into the ocean

Atmospheric pollutants

Result from oil combustion: CO2, SO2, NOx, CO, smoke particulates

Global warming effects

Include sea level rise, land ice melt, increased storm events

Tertiary oil recovery

Reduces oil viscosity using steam, solvents, bacteria, or detergents

Directional drilling

Specialized drills for horizontal and vertical access to oil deposits

Remotely operated vehicles (ROVs)

Inspect seabed and pipelines, complete minor repairs underwater

Natural gas properties

Non-renewable, high energy density, depletable, high abundance

Biogas

Methane from livestock waste or anaerobic decomposition, combusted for heat

Hydraulic fracturing (fracking)

High-pressure water underground to release trapped oil and gas

Methane hydrate

Solid structure in marine sediments holding methane gas

Carbon capture and storage (CCS)

Storing carbon underground in previous oil and gas mines to reduce warming

Enhanced gas recovery

Increasing pressure in gas fields for higher extraction rates