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).
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.
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).