Science & Technology in Action

4th Edition

Energy Needs and Global Warming

Shell

In an energy-hungry world it is becoming ever more important to develop alternative energy sources to gradually replace fossil fuels where possible. At present less than 2% of global energy is derived from alternative energy sources.
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Contains the full lesson along with a supporting toolkit, including teachers’ notes.

Lesson excerpt

Fossil fuel reserves are in general becoming less accessible and more costly to exploit. Demand for energy is constantly growing. Consequently there are valid concerns about the availability and sustainability of energy supplies for future generations. In the past 150 years global temperatures have risen about 0.6 °C and the trend at present seems to be upward. This has serious economic and demographicimplications.

The growing global energy demand
The population of the world is growing and will increase from 6 billion to 9 billion by 2050. Population growth means greater economic activity, which creates higher demand for energy. Higher energy consumption based on fossil fuels implies higher CO2 emissions. Countries such as China and India are entering energy intensive phases of their development; this puts greater pressure on global energy resources. As people’s living standards increase so does their energy usage. Today, China has an estimated 40 million cars – three for every 100 people – and by 2020 this will increase to about 150 million.

The worlds’ conventional oil fields are in decline; so called ‘easy oil’ (conventional oil with easy extraction) is becoming increasingly difficult to find. New technologies are needed to extract unconventional energy sources such as oil sands, deep ocean oil and artic oil.

Oil sands are a mixture of clay, sand, water and bitumen.Bitumen is a thick tar-like form of petroleum. Oil sand mining does not require conventional drilling techniques; the sand is removed using mechanical shovels and trucks. It is then mixed with warm water. The oil separates from the water and, because it has a lower density, it rises to the surface. New treatment methods have been developed that reduce the costs and improve the energy efficiency of oil sand extraction. This reduces greenhouse gasemissions by 40,000 tonnes a year. A major difficulty in extracting this unconventional energy source has been overcome.

Exploration
Oil is most often found trapped below an impervious rock layer.Seismic surveys are used to map the layers in the earth’s surface and locate likely sites of oil deposits. Sophisticated computer programmes have been developed to analyse the large amounts of seismic data.

Recent technology has made use of electromagnetic waves to locate oil deposits. The signal sent out changes depending on the strength of a material opposing the flow of electric current.

Quiz questions

  1. Fossil fuels are a fuel source of hydrocarbons found within the top layers of the earths crust. true
  2. Higher energy consumption based on fossil fuels implies higher CH 4 emissions. false
  3. Ozone is the gas which causes about 27-30% of the greenhouse effect. false
  4. Fractional distillation is a method of separating out the different mixtures from crude oil according to their melting points. false
  5. Carbon dioxide emissions can be reduced using techniques such as carbon capture and storage. true
  6. Seismic and electromagnetic waves are techniques used to locate oil deposits below the earth’s surface. true
  7. Methane is a more effective greenhouse gas than carbon dioxide. true
  8. Climate change could cause a major increase in insect-borne diseases like malaria throughout Europe, Asia and North America. true