Energy is a major component of OECD economies in and of itself and as a factor input to all other economic activities. Energy production and use have environmental effects that differ greatly by energy source. Fuel combustion is the main source of local and regional air pollution and GHG emissions. Other effects involve water quality, land use, risks related to the nuclear fuel cycle and risks related to the extraction, transport and use of fossil fuels.
The structure of a country's energy supply and the intensity of its energy use, along with changes over time, are key determinants of environmental performance and the sustainability of economic development. The supply structure varies considerably among countries. It is influenced by demand from industry, transport and households, by national energy policies and by national and international energy prices.
The indicators presented here relate to:
Energy intensities, expressed as total primary energy supply (TPES) per unit of GDP and per capita. Total primary energy supply (TPES) equals production plus imports minus exports minus international bunkers plus or minus stock changes.
Energy intensity does not reflect energy efficiency, as the latter depends on numerous elements (climate, output composition, outsourcing of goods produced by energy-intensive industries, etc.) that are not considered by the simple measure of energy supply to GDP.
The energy supply mix, i.e. the structure of energy supply in terms of primary energy source as a percentage of total energy supply excluding heat output from non-specified combustible fuels, electricity and heat.
In the 1990s and 2000s, energy intensity per unit of GDP generally decreased for OECD countries overall as a consequence of structural changes in the economy and energy conservation measures, and, in some countries, decreases in economic activity and the transfer of energy-intensive industries to other countries. Such outsourcing may increase pressures on the global environment if less energy efficient techniques are involved.
Progress in per capita terms has been much slower, reflecting an overall increase in energy supply (+26%) and energy demand for transport (+17%):
Variations in energy intensity among OECD countries are wide (from 0.09 to 0.54 per unit of GDP, from 1.5 to 18 per capita). They depend on national economic structure and income, geography, energy policies and prices, and countries' endowment in different types of energy resources.
While some decoupling of environmental effects from growth in energy use has been achieved, results to date are insufficient to effectively reduce air and GHG emissions from energy use.
Growth in total primary energy supply was accompanied by changes in the fuel mix. While OECD countries are still more than 80% reliant on fossil fuels, the shares of solid fuels and oil fell, while those of gas and other energy sources rose.
Several OECD countries have made progress in promoting renewables in their energy mixes. Overall however, the share of renewable energy has remained relatively stable for the OECD and accounts for about 9% of total supply, with a slight increase in recent years reflecting the growing role of bioenergy, liquid biofuels and wind in some countries. Biomass and hydro still represent the largest shares.
See Annex A for OECD decoupling trends and energy mix.
Data quality is not homogeneous for all countries. In some countries, data are based on secondary sources, and where incomplete, estimates were made by the IEA. In general, data are likely to be more accurate for production and trade than for international bunkers or stock changes; and statistics for biofuels and waste are less accurate than those for traditional commercial energy data.