Primary Energy supply

An analysis of energy problems requires a comprehensive presentation of basic supply and demand data for all fuels in a manner which will allow the easy comparison of the contribution each fuel makes to the economy and their interrelationships through the conversion of one fuel into another. This type of presentation is suitable for the study of energy substitution, energy conservation and forecasting.

Definition

The table refers to total primary energy supply (TPES). TPES equals production plus imports minus exports minus international marine bunkers plus or minus stock changes. The IEA energy balance methodology is based on the calorific content of the energy commodities and a common unit of account. The unit of account adopted by the IEA is the tonne of oil equivalent (toe) which is defined as 107 kilocalories (41.868 gigajoules). This quantity of energy is, within a few per cent, equal to the net heat content of 1 tonne of crude oil. The difference between the "net” and the "gross” calorific value for each fuel is the latent heat of vaporisation of the water produced during combustion of the fuel. For coal and oil, net calorific value is about 5% less than gross, for most forms of natural and manufactured gas the difference is 9-10%, while for electricity there is no difference as the concept has no meaning in this case. The IEA balances are calculated using the physical energy content method to calculate the primary energy equivalent. The forecasts provided in the table refer to the Reference Scenario of the World Energy Outlook. The Reference Scenario projects supply and demand if present policies were to continue. The World Energy Outlook also presents an Alternative Policy Scenario which analyses how the global energy market could evolve if countries were to adopt all of the policies they are currently considering related to energy security and energy-related CO₂ emissions.

Comparability

While every effort is made to ensure the accuracy of the data, quality is not homogeneous for all countries/regions. In some countries data are based on secondary sources, and where incomplete or unavailable, the IEA has made estimates. In general, data are likely to be more accurate for production and trade than for international marine bunkers or stock changes. Moreover, statistics for combustible renewables and waste are less accurate than traditional commercial energy data in most countries.