World Energy Consumption

The present global yearly primary energy1 consumption is, in round figures, about 500EJ.2 This is equivalent to about 1.4 x1017 Wh or 140000TWh . Dividing this figure by the number of hours in the year gives 16TW or 16000 GW as the average rate of world primary power

1 Primary energy is the gross energy before its transformation into other more useful forms like electricity. 2The unit of energy in the SI system is the joule, denoted by J. Multiples of joule are kJ, MJ, GJ, TJ (T for tera denoting 1012) and EJ (E for Exa denoting 1018); the unit of power is the Watt (W) and represents the rate of work in joules per second. Electrical energy is usually charged in watt-hours (W h) or kW h. Joules can be converted into Wh through division by 3600.

Renewable Energy in Power Systems Leon Freris and David Infield © 2008 John Wiley & Sons, Ltd






nuclear 6.5%


natural gas



large hydro



coal 25.1%


biomass and

waste 10.6%


oil 34.3%

Figure 1.1 Percentage contribution to world primary energy consumption. The pie chart in Figure 1.1 shows the percentage contribution to world primary energy from the different energy sources according to data taken from the International Energy Agency (IEA) Key World Energy Statistics, 2006.

The world demand for oil and gas is increasing significantly each year. The major part of this increase is currently taken up by India and China where industrialization and the demand for consumer products is escalating at an unprecedented pace. The world consumption in 2006 increased by more than twice Britain's total annual energy use and is the largest global yearly increase ever recorded. China alone accounted for roughly 40% of this increase. The IEA forecasts that by 2030 demand for energy will be some 60% more than it is now.

Renewable Energy 101

Renewable Energy 101

Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable. The usage of renewable energy sources is very important when considering the sustainability of the existing energy usage of the world. While there is currently an abundance of non-renewable energy sources, such as nuclear fuels, these energy sources are depleting. In addition to being a non-renewable supply, the non-renewable energy sources release emissions into the air, which has an adverse effect on the environment.

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