Energy sources

Nature of science:

Use theories to explain natural phenomena—energy changes in the world around us result from potential and kinetic energy changes at the molecular level. Energy has both quantity and quality. (2.2)

• A useful energy source releases energy at a reasonable rate and produces minimal pollution.
• The quality of energy is degraded as heat is transferred to the surroundings. Energy and materials go from a concentrated into a dispersed form. The quantity of the energy available for doing work decreases.
• Renewable energy sources are naturally replenished. Non-renewable energy sources are finite.
• Energy density
• Speci¢ic energy
• The effeciency of an energy transfer

Applications and skills:

• Discussion of the use of different sources of renewable and non-renewable energy.
• Determination of the energy density and specific energy of a fuel from the enthalpies of combustion, densities and the molar mass of fuel.
• Discussion of how the choice of fuel is influenced by its energy density or specific energy.
• Determination of the efficiency of an energy transfer process from appropriate data.
• Discussion of the advantages and disadvantages of the different energy sources in C.2 through to C.8.

• The International Energy Agency is an autonomous organization based in Paris which works to ensure reliable, affordable and clean energy for its 28 member countries and beyond.
• The International Renewable Energy Agency (IRENA), based in Abu Dhabi, UAE, was founded in 2009 to promote increased adoption and sustainable use of renewable energy sources (bioenergy, geothermal energy, hydropower, ocean, solar and wind energy).

Theory of knowledge:

• “I have no doubt that we will be successful in harnessing the sun’s energy. If sunbeams were weapons of war we would have had solar energy centuries ago.” (Lord George Porter). In what ways might social, political, cultural and religious factors affect the types of research that are financed and undertaken, or rejected?
• There are many ethical issues raised by energy generation and its consequent contributions to pollution and climate change.What is the influence of political pressure on different areas of knowledge?

Utilization:

• Syllabus and cross-curricular links:
• Topic 5.1—enthalpies of combustion
• Topic 10.2—the combustion of hydrocarbons
• Environmental systems and societies topics—3.2, 3.3, 3.5 and 3.6
• Physics topic 8.1—energy density

• Aim 1: Discussions of the possible energy sources provide opportunities for scientific study and creativity within a global context.
• Aim 6: The energy density of different fuels could be investigated experimentally.
• Aim 7: Databases of energy statistics on a global and national scale can be explored here.
• Aim 8: Energy production has global economic and environmental dimensions. The choices made in this area have moral and ethical implications.