6.5C Unconventional Fossil Fuel Energy Sources

• Unconventional Sources of Fossil Fuel

  -> There are four main unconventional sources of fossil fuel which have the potential to help meet future energy demands

  • Tar sands
  • Oil shale
  • Shale gas
  • Deepwater oil
• Tar sands:

  • Mixture of clay, sand, water and bitumen (a heavy, viscous oil)
  • Have to be mined and then injected with steam to reduce the viscosity of the tar so it can be pumped out

  -> Biggest deposits are in Canada and Venezuela. 

  -> Tar sands produce about 40% of Canada’s oil output
• Oil shale:

  • Oil-bearing rocks that are permeable enough to allow oil to be pumped out
  • Mined or shale is ignited so that the light oil fractions can be pumped out
  • Little exploration has taken place
• Shale gas:

  • Natural gas that is trapped in fine-grained sedimentary rocks
  • Fracking - pumping in water and chemicals forces out the gas

  -> The USA is the leading producer and exporter 

  -> In 2015, shale gas provided 25% of the USA’s gas supply
• Deepwater oil:

  • Oil and gas found offshore and at considerable oceanic depths
  • Drilling takes place from ocean rigs

  -> Huge oil deposits were discovered off the coast of Brazil in 2006 and Brazil are leading the way in this
• negatives associated with these unconventional sources:

  • The exploitation of these sources will continue to threaten the carbon cycle and contribute to global warming
  • Extraction is expensive and requires lots of complex technology, energy and water
  • Extraction can cause environmental damage
  • Scars of opencast mines and possible ground subsidence
  • Contamination of groundwater sources and oil spills