Manfred Lenzen Richard Wood And Barney Foran

Centre for Integrated Sustainability Analysis, A28, The University of Sydney NSW 2006, Australia

4.1 Introduction: What is Embodied Energy?

Living means consuming, and consuming means needing energy. Most of the energy resources we consume today are non-renewable - hence there is the obvious problem of their depletion, among other problems of environmental pollution and climate change. We as householders are familiar with using energy in our homes - residential energy - mainly in the form of electricity for our appliances, as gas for cooking, or as firewood for space heating. We also use transport energy in the form of petrol in our private cars, and possibly in boats and other vehicles. The consumption of residential and transport energy is called direct energy consumption (Bin and Dowlatabadi 2005, p. 199). We experience direct energy daily, as heat, cooling, or motion. More than that, we experience that heat dissipates, and motion ceases when the energy source is switched off. We therefore have quite an intuitive feeling for the fact that consuming energy involves the irreversible use of a finite resource.

Consuming also means needing goods and services, ranging from 'material' items such as food, clothing, water, appliances, vehicles and equipment to 'immaterial' amenities such as entertainment, public transport, insurance and personal care. These commodities come to us ready to use, and they usually do not evoke any association with energy. However, producing goods and services requires substantial amounts of energy to be used - on farms, in factories, in power plants, and by corporate and public vehicles. The energy that is needed throughout the entire life cycle of a final consumer item - good or service - starting with the transformation of raw materials and ending with its final disposal, is often called the energy embodied in the consumer item.1 We have often no idea how much energy is needed to produce the things we buy, and whether all of the embodied energy is higher than the direct energy we experience using in our daily lives.

These questions (and a fair few suggested answers for that matter) are not new; in fact, some of the 1970s references cited in this chapter read as if they were written in the twenty-first century. What have improved though are the analytical tools applied to these questions and the quantitative sophistication of their answers. The next section explores embodied

1 Alternative terms are 'embedded energy', 'indirect energy', 'life-cycle energy', 'cradle-to-grave energy', or 'supply-chain energy'.

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□ Commercial and public services

OECD North America OECD Pacific OECD Europe Middle East Latin America Non-OECD Europe Former USSR East Asia Africa South Asia

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OECD North America OECD Pacific OECD Europe Middle East Latin America Non-OECD Europe Former USSR East Asia Africa South Asia World

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Fig. 4.1. World energy consumption by region and usage (International Energy Agency 2007). (a) Absolute values in PJ (1015 joules), (b) Percentage distribution across usage categories.

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energy research and its findings about consumer items, trends over time, and the role of international trade. In particular, we investigate whether there are certain influential socio-economic-demographic traits, whether embodied energy exceeds direct energy or not, and whether international trade displaces the environmental and resource impacts of wealthy countries' energy-hungry consumption into low income countries. Following is an empirical case study of households in Australia's largest city, Sydney. The chapter concludes with an outline of the implications of embodied energy for urban lifestyles, both present and future.

I t should also be noted that what can be said of energy can also be said of other resources, and also pollutants. Consuming also means using water, or emitting greenhouse gases. Once again, we can experience direct water use as it comes out of our taps, and direct greenhouse gas emissions from our cars and fireplaces. Rarely though do we think about irrigation water embodied in our food,2 or greenhouse gas emissions embodied in our aluminium window frames. The indicator dealt with in this chapter - energy - is a good proxy for other environmental impacts, especially emissions from fuel combustion, such as CO2, NO2, and SO2, for example (Schipper 1998).

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  • antje meier
    How much energy do we use to transport wood?
    9 years ago

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