The Growth of Electricity Through The Ages

Before the industrial revolution, humans relied on natural energy flows and animal and human power for heat, light and work. Draft animals, wind and water were the only sources of mechanical energy. The only form of energy conversion (from chemical energy to heat and light) came from burning various forms of biomass. The per capita use of energy did not exceed 0.5 tons of oil-equivalent (toe) annually.

Most of this occurred in industrialized societies, which had come to rely heavily on the ready availability of energy. On a per capita basis, people in these societies now use more than 100 times the quantity of energy that was used by their ancestors before humans learned to exploit the energy potential of fire.

As societies industrialized, they not only began to use more energy, but also began to use energy in different forms, typically switching—as household incomes rose—from such traditional fuels as wood, crop residues and dung to such commercial forms of energy.Reliable estimates of the use of traditional waste and biomass are difficult to obtain, but these fuels are estimated to account for approximately 20 percent of overall primary energy use. Much of this use is concentrated in the rural areas of developing countries.

Harnessing oxen increased the power available to human beings by a factor of ten. The waterwheel increased it by an additional factor of six and the steam engine by another factor of ten (UNDP, 2000, p. 3). Cumulatively, these innovations increased the power that was available to humans by a factor of 600. The development of the steam engine—initially powered by coal—was particularly important. It enabled the provision of energy services to become site-independent because coal could be transported and stored anywhere. Steam engines fuelled the factory system and the industrial revolution. By the end of 19th century, coal provided almost all of the primary energy needs of the industrializing countries.

Even as technologies like the steam engine vastly increased the power available to humans, improvements in energy-producing and -using technologies steadily increased the efficiency at which energy could be converted to different forms and used to deliver goods and services.

Massive improvements in the efficiency of technologies and devices have facilitated continuing reductions in the quantity of energy required to produce a unit of goods and services in industrialized economies. This has resulted in the “decoupling” of economic output from energy consumption—two measures which, until recently, were assumed to grow more or less in lockstep with each other.

Overall, the energy intensity of the OECD countries—where energy intensity is measured simply as the ratio of GDP to primary energy consumption—has been declining in recent years by an average rate of 1.3 percent per year. Interestingly, energy intensity has been falling even faster in non-OECD countries, because many are in the process of modernizing from a fairly inefficient industrial base. It is worth emphasizing that electricity intensity throughout the world has not been declining. Consequently, the growth of electricity has been outpacing the rate of economic growth in all regions in recent years.