Time: 9 hours
Level: Introductory
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| | Introduction Introduction Resource- Access to safe, clean and sustainable energy supplies is one of the greatest challenges facing humanity during the twenty-first century. This unit will survey the world’s present energy systems and their...
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| | 1 Energy sources and environmental impact- 1.1 Where do we get our energy from? Resource
- The world’s current energy systems have been built around the many advantages of fossil fuels, and we now depend overwhelmingly upon them. Concerns that supplies will ‘run out’ in the short-to-medium term...
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| | 2 Definitions: energy, sustainability and the future |
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| | 3 Present energy sources and sustainability- 3.1 Introduction Resource
- So what are the principal energy systems used by humanity at present, and how sustainable are they?
- 3.2 Fossil fuels Resource
- So what are the principle energy systems used by humanity at present, and how sustainable are they?
- 3.3 Nuclear energy Resource
- Nuclear energy is based on harnessing the very large quantities of energy that are released when the nuclei of certain atoms, notably uranium-235 and plutonium-239, are induced to split or ‘fission’. The...
- 3.4 Bioenergy Resource
- Not all fuel sources are, of course, of fossil or nuclear origin. From prehistoric times, human beings have harnessed the power of fire by burning wood to create warmth and light and to cook food.
- 3.5 Hydroelectricity Resource
- Another energy source that has been harnessed by humanity for many centuries is the power of flowing water, which has been used for milling corn, pumping and driving machinery. During the twentieth century,...
- 3.6 Summary Resource
- This section has described how fossil fuels provide the majority of the world's energy requirements, with bioenergy, nuclear energy and hydropower also making major contributions. The other ‘renewable’...
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| | 4 Renewable energy sources- 4.1 What are renewable energy sources? Resource
- Fossil and nuclear fuels are often termed non-renewable energy sources. This is because, although the quantities in which they are available may be extremely large, they are nevertheless finite and so...
- 4.2 Solar energy Resource
- Solar energy, it should firstly be stressed, makes an enormous but largely unrecorded contribution to our energy needs. It is the sun's radiant energy, as noted in Box 2, that maintains the Earth's surface...
- 4.3 Indirect use of solar energy Resource
- The above examples illustrate the direct harnessing of the sun's radiant energy to produce heat and electricity. But the sun's energy can also be harnessed via other forms of energy that are indirect manifestations...
- 4.4 Non-solar renewables Resource
- The energy that causes the slow but regular rise and fall of the tides around our coastlines is not the same as that which creates waves. It is caused principally by the gravitational pull of the moon...
- 4.5 Sustainability of renewable energy sources Resource
- Renewable energy sources are generally sustainable in the sense that they cannot ‘run out’ – although, as noted above, both biomass and geothermal energy need wise management if they are to be used sustainably....
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| | 5 Energy services and efficiency improvement- 5.1 Energy services Resource
- Except in the form of food, no one needs or wants energy as such. That is to say, no one wants to eat coal or uranium, drink oil, breathe natural gas or be directly connected to an electricity supply....
- 5.2 Energy efficiency improvements Resource
- On the supply side of our energy systems, there is a very large potential for improving the efficiency of electricity generation by introducing new technologies that are more efficient than older power...
- 5.3 The rebound effect Resource
- When individuals or organisations implement energy efficiency improvements, they usually save money as well as saving energy. However, if the money saved is then spent on higher standards of service, or...
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| | 6 Energy in a sustainable future- 6.1 Introduction Resource
- So far, we have briefly introduced three key approaches to improving the sustainability of human energy use in the future. These are:
- 6.2 (a) ‘Cleaning-up’ fossil and nuclear technologies Resource
- This means mitigating some of the adverse ‘environmental’ consequences of fossil and nuclear fuel use through the introduction of new, ‘clean’ technologies that should substantially reduce pollution emissions...
- 6.3 (b) Switching to renewable energy sources Resource
- The use of renewable energy usually involves environmental impacts of some kind, but these are normally lower than those of fossil or nuclear sources.
- 6.4 (c) Using energy more efficiently Resource
- This, as we have seen, involves a mixture of social and technological options, applied at the demand-side of the energy chain.
- 6.5 Changing patterns of energy use Resource
- Before considering the feasibility, and the plausibility, of radical changes in patterns of energy production and consumption, of the kind that will be needed during the first half of the twenty-first...
- 6.6 Long-term energy scenarios Resource
- To begin to understand the range of long-term future possibilities, let us look briefly at two major studies of future sustainable energy options, the first addressing the UK situation, the second taking...
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| | References and Acknowledgements |
