EARTHTRENDS DATA TABLES For more information, please consult http://earthtrends.wri.org TECHNICAL NOTES: ENERGY CONSUMPTION BY SOURCE DEFINITIONS AND METHODOLOGY Basic energy statistics are collected by the the International Energy Agency (IEA) from a variety of sources. In OECD member countries, national administrations fill out five annual questionnaires. In non-OECD countries, statistics are collected from questionnaires, international organizations such as United Nations, co-operation with national statistical bodies, and direct communication with energy consultants and companies. If data are not available from any of these sources, they are estimated by the IEA. To facilitate comparisons among different sources of energy, the IEA measures the heat content of all energy commodities in metric tons of oil equivalent (toe). A toe measures the energy contained in a metric ton (1000 kg) of crude oil. One toe is equal to 10 Exp. 7 kilocalories, 41.868 gigajoules, or 11,628 gigawatt-hours (GWh). The energy produced by fossil fuels is calculated using conversion factors per unit mass of fuel (eg. 10,000 kcal/kg of oil). Since energy sources such as coal and crude oil may vary in quality, the IEA uses specific conversion factors supplied by national administrations for the main categories of energy sources and uses (i.e. production, imports, exports). The energy produced by non-fossil fuels is more complicated to measure; the IEA must first assume a primary form of energy to measure, and then calculate the primary energy equivalent. Total heat is the primary form of energy for nuclear heat and electricity, geothermal heat and electricity, and solar heat production. For hydro, wind, wave and photovoltaic solar electricity production, total electricity is the primary form of energy. The IEA determines the physical energy content of the primary energy source using global or regional efficiency averages. Total Energy Production is defined as the total production of primary energy. Primary energy includes hard coal, lignite, peat, crude oil, natural gas liquids (NGLs), natural gas, nuclear, hydro, geothermal, solar and the heat from heat pumps that is extracted from the ambient environment. Primary energy includes losses from transportation, friction, heat loss and other inefficiencies. Production is calculated after impurities are removed. Total Energy Consumption is defined as the amount of primary energy used by a particular country or region. Consumption equals indigenous production plus imports minus exports plus stock changes minus energy delivered to international marine bunkers. IEA refers to these data as Total Primary Energy Supply (TPES). Energy losses from transportation, friction, heat, and other inefficiencies are included in these totals. The total amount of primary energy refers to the energy consumed from all sources including fossil, nuclear, hydroelectric, modern renewables, traditional renewables, and all renewable fuels and waste. Energy Consumption (as a percent of total consumption) by Source is the percentage of the total amount of primary energy consumed from a given energy source. Non-Renewable Energy Sources include coal and coal products, oil, and natural gas. Coal and Coal Products includes energy in the form of both primary and derived coal fuels: hard coal, lignite, patent fuel, coke, blast furnace gas, and peat. Oil includes the amount of primary energy in the form of crude oil, petroleum products, natural gas liquids, refinery feedstocks, and other hydrocarbons. The inclusion of petroleum products accounts for domestic processing of crude oil as well as assorted petroleum imports. Petroleum products refers to refinery gas, ethane, liquefied petroleum gas, aviation gasoline, motor gasoline, jet fuels, kerosene, gas/diesel oil, heavy fuel oil, naphtha, white spirit, lubricants, bitumen, paraffin waxes, and petroleum coke. Natural Gas includes primary energy from fossil fuels in the gaseous state. Natural gas liquids (NGLs) are excluded. Nuclear energy shows the primary heat equivalent of the electricity produced by nuclear power plants. Heat-to-electricity conversion efficiency is assumed to be 33% (the average thermal efficiency in Europe). Renewable Energy Sources consist of fuels obtained from sources that are essentially inexhaustible and include wood, waste, geothermal, wind, photovoltaic, and solar thermal energy. Hydroelectric includes the energy content of the electricity produced in hydro power plants, excluding output from pumped storage tanks. Solid Biomass includes the amount of primary energy from plant matter used directly as fuel or converted into other forms before combustion. Solid Biomass includes fuel wood, vegetal waste (including wood waste and crops used for energy production), animal materials/wastes, sulphite lyes (also known as "black liquor"), and other solid biomass. Inputs to charcoal production are included here. However, since charcoal is a secondary product, the IEA excludes final charcoal production numbers to avoid double counting. Biogas & Liquid Biomass is the amount of primary energy produced by liquid biomass, which includes bio-additives such as ethanol (alcohol), and biogas, which is produced by the fermentation of animal dung, human sewage or crop residues. Geothermal energy is generated using trapped underground heat and includes energy used directly for heat and for electricity generation. Unless the actual efficiency of the electricity generation is known, the quantity of geothermal energy entering electricity generation is inferred using an average thermal efficiency of 10 per cent. Solar includes the production of electricity from solar photovoltaic cells as well as solar thermal energy. Solar thermal (heat) energy is used for both hot water production and electricity generation. Solar heat is collected with flat plate collectors for water heating or in solar thermal-electric plants. Passive solar energy for the direct heating, cooling and lighting of dwellings or other buildings is not included here. Wind uses the mechanical energy of the wind for generating electricity. Tide, Wave & Ocean includes the production of electricity from the mechanical energy of ocean waves and tides or from the thermal energy (heat) stored in the ocean. FREQUENCY OF UPDATE BY DATA PROVIDERS The IEA updates energy data each year in June for OECD countries and in September for non-OECD countries, often revising data from earlier years. DATA RELIABILITY AND CAUTIONARY NOTES The energy balances data are primarily based on well-established and institutionalized accounting methodologies, and are therefore considered reliable. Energy production estimates from nuclear power and renewable sources (hydroelectric, solar, geothermal, and wind power) are calculated using a number of assumptions about primary energy forms and plant efficiencies. As a result, these values may be less reliable than estimates of energy produced from fossil fuels, and the share of renewables in total energy supply may appear different here than it would from other providers. These statistics are expressed in terms of "net" calorific value, so the values reported here may be slightly lower than those in other statistical compendia which report energy in terms of "gross" calorific value. The data as received from the provider do not distinguish between no data and zero values. WRI has distinguished between the two where possible, but some values represented as zero should probably be indicated as missing and vice versa. Extreme caution should be exercised if considering using the data to extrapolate into the future. Energy usage is extremely variable from year to year due to short-term factors, such as the weather and the economy, that significantly impact any one year's consumption. SOURCE International Energy Agency (IEA), 2005. Energy Balances of OECD Countries (2003 Edition) and Energy Balances of non-OECD Countries (2003 Edition). Electronic database available online at: http://www.iea.org/Textbase/subjectqueries/index.asp Paris: Organization for Economic Cooperation and Development (OECD).