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An introduction to energy resources
An introduction to energy resources

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2.2 Present-day energy use

Global annual consumption of all forms of primary energy increased more than tenfold during the 20th century (Figure 1.1), and by the year 2002 reached an estimated 451 EJ. About three-quarters of this energy came from coal, oil and gas (Figure 1.4).

Figure 1.4 Contributions of various energy sources to global primary energy consumption in 2002. 'Renewables' and 'biomass' will be defined in Sections 1.6.2 and 1.7.

Question 2

If the global annual energy consumption is 451 EJ, what would be the average rate of consumption each second of every day, i.e. the global power demand?

Answer

Make a note of these equivalent amounts, as you will be comparing them with the energy and power available from various sources later.

With a global population of 6.5 billion, each person's 'drain' on primary energy is, on average, around 73 GJ per year. But globally, there are major regional differences in energy consumption (Figure 1.5a). Developed countries, with industrial as well as domestic demands, use energy in vast quantities and at alarming rates. In North America it is around 350 GJ per person per year, nearly five times the global average, and totalling around 28% of global energy use by about 4.5% of world population. People in Europe and the former Soviet Union use about double the global average. Figure 1.5b, which shows the amount of lighting seen from space at night, gives a graphic picture of the inequalities of energy use.

Figure 1.5 (a) Energy consumption by region, in GJ per person per year, 2004. (b) Composite satellite image of the Earth at night. The white areas show outside lighting.

In 2002, UK primary energy used was the equivalent of 9.7 EJ: about 164 GJ for each of the 59 million people in the UK, just over double the global average. About one-fifth of the UK's primary energy requirement is used in the home, 30% lost in conversion and most of the rest for services, transport and industry (Figure 1.6 below).

Figure 1.6 UK primary energy by fuel, and delivered energy by fuel, sector and end use 2000.