Fossil fuel power production

8.3.1 Outline the historical and geographical reasons for the widespread use of fossil fuels.

Fossil Fuel Power Production
Fossil Fuel Power Production

Fossil fuels include coal, oil, and natural gases. They are produced over a time scale that involves tens or hundred of millions of years from accumulations of dead matter. Over this time period, the matter was converted into fossil fuels by exposure to very high temperatures and pressure that exist beneath the Earth's surface.

The industrial revolution took place in Western Europe in the late 18th, and early 19th centuries in which large-scale manufacturing industries were developed and the factory as a place of work was introduced. Three important inventions are:
  • Machines that allowed materials for textiles to be manufactured. For example, the cotton mill that was invented at the beginning of the industrial revolution.
  • The improvement and the invention of the steam engine, which allowed factories to be built without the reliance on the flow of water.
  • The development of iron smelting industries. This allowed iron and steel to be produced at a cheap cost, allowing the growth of the industries that are based around iron and steel.

Industrialization led to a higher rate of energy usage, leading to industry being developed near to large deposit of fossil fuels.

From Tim Kirk.

8.3.2 Discuss the energy density of fossil fuels with respect to the demand of power stations.

Energy Density of Fossil Fuels
Energy Density (MJ kg-1)

Using the information above, we are able to calculate the typical rate at which coal must be supplied to a 500MW coal fired power station.

Electrical Power Supply = 500 MW = 5 × 108 Js-1
Power Released from Fuel = 5 × 108 / Efficiency
= 5 × 108 / 0.35
= 1.43 × 109 Js-1

Rate of Consumption of Coal = Energy/Density
= 1.43 × 109 / 3.3 × 107 kg s-1
= 43.3 kg s-1
= 43.3 × 60 × 60 kg hr-1
≈ 160 tonnes hr-1

By calculating the results for the fossil fuels, we can notice that the higher the energy density, the less mass is needed.

From Tim Kirk.

8.3.3 Discuss the relative advantages and disadvantages associated with the transportation and storage of fossil fuels.

Pretty environmentally unfriendly...
Pretty environmentally unfriendly...

  • Convenient Storage - can be built anywhere with good transport links and water availability.
  • Easy to transport.
  • Economical - cheap compared to other sources of energy.
  • Very high energy density - a great deal of energy is released from a small mass.
  • Can be used directly by people at such places like home to provide heating.

  • Environmentally Ugly.
    • Combustion products produce pollution, such as acid rain.
    • Combustion products contain greenhouse gases.
  • Non-renewable.
  • Coal-fired power stations need large amounts of fuel.

From Tim Kirk.

8.3.4 State the overall efficiency of power stations fueled by different fossil fuels.

The efficiency of different power stations depends on the design:
Fossil Fuel
Typical Efficiency
Current Maximum Efficiency
Natural Gas
*Considering the thermodynamics associated with heat engines and heat pumps, the maximum efficiency that can be achieved by these power stations is limited.

8.3.5 Describe the environmental problems associated with the recovery of fossil fuels and their use in power stations.

The recovery of fossil fuels often uses methods that are disruptive to the environment; harming trees, mountains, land, and water sources
  • Recovered by
    • Surface Mining
    • Deep Mining
      • Involves digging shafts and tunnels.
  • Problems
    • Land destruction.
    • Wastes from mining.
    • Risks of
      • Water contamination.
      • Flooding.
external image oil_prod_img_4.gif
Natural Gases
  • Recovered by
    • Wells drilled into underground porous rock that pumps gas to the surface.
  • Problems
    • Methane Emissions
    • Water Contamination

  • Recovered by
    • Wells drilled into non-porous rock.
    • Obtained by
      • Pumping.
      • Flooding wells with high-pressure water or gas.
      • Oil can be heated and scrubbed out.
  • Problems
    • Toxic chemicals are released.
    • Oil spills.
    • Destroys the natural habitat.

Tim Kirk, 2007