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Energy Statistics Yearbook -
Definitions
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Introduction
| Definitions
Abbreviations and Symbols | Conversion
factors
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Production:
The data on production refer to the first stage of production: accordingly,
for hard coal the data refer to mine production; for briquettes to
the output of briquetting plants; for crude petroleum and natural
gas to production at oil and gas wells; for natural gas liquids to
production at wells and processing plants; for refined petroleum products
to gross refinery and plant output; for cokes and coke oven gas to the output
of ovens; for other manufactured gas to production at gas works, blast
furnaces or refineries; and for electricity to the gross production
of generating plants.
Imports and Exports:
The international trade of energy commodities is based on the "general
trade" system, that is, all goods entering and leaving the national
boundary of a country are recorded as imports and exports.
Bunkers:
refer to fuels supplied to ships and aircraft engaged in international
transportation, irrespective of the carrier's flag.
Variation of stocks:
In general, data on stocks refer to changes in stocks at producers,
importers and/or industrial consumers at the beginning and end of each
year. In some cases, however, stock series have been derived on the
basis of the difference between gross availabilities for transformation
or consumption and official or published data on actual consumption.
A positive stock change (+) reflects additions to stocks which in effect
decreases "apparent consumption"; while a negative stock change
(-) creates exactly the opposite result.
Consumption:
Data on consumption refer to "apparent consumption" and are
derived from the formula "production + imports - exports - bunkers
+/- stock changes." Accordingly, the series on apparent consumption
may occasionally represent only an indication of the magnitude of actual
(i.e., "measured") gross inland availability. This statement
is particularly suitable either when stock data are unavailable or unreliable,
or when apparent consumption is a small residual element derived from
calculations between large aggregate series and thus is sensitive to
small variations in these series. This latter point is also appropriate
with respect to the per capita consumption calculations presented in
some tables. Where the quantities involved are small, the series tend
to exaggerate the effects of such elements as stock additions or withdrawals.
Hard coal:
Coal that has a high degree of coalification with a gross calorific value
above 23,865 KJ/kg (5,700 kcal/kg) on an ash-free but moist basis, and
a mean random reflectance of vitrinite of at least 0.6. Slurries, middlings
and other low-grade coal products, which cannot be classified according
to the type of coal from which they are obtained, are included under hard
coal. There are two sub-categories of hard coal: (i) coking coal and (ii)
other bituminous coal and anthracite (also known as steam coal). Coking
coal is a hard coal with a quality that allows the production of coke
suitable to support a blast furnace charge. Steam coal is coal used for
steam raising and space heating purposes and includes all anthracite coals
and bituminous coals not classified as coking coal.
Lignite:
One of the two sub-categories of brown coal. Brown coal is coal with a
low degree of coalification which retained the anatomical structure of
the vegetable matter from which it was formed. It has a mean random reflectance
of vitrinite of less than 0.6, provided that the gross calorific value
(on a moist ash-free basis) is less than 23,865 KJ/kg (5,700 kcal/kg).
Brown coal comprises: (i) lignite - non-agglomerating coals with a gross
calorific value less than 17,435 KJ/kg (4,165 kcal/kg) and greater than
31 per cent volatile matter on a dry mineral matter free basis and (ii)
sub-bituminous coal - non-agglomerating coals with a gross calorific value
between 17,435 KJ/kg (4,165 kcal/kg) and 23,865 KJ/kg (5,700 kcal/kg)
containing more than 31 per cent volatile matter on a dry mineral matter
free basis.
Peat:
A solid fuel formed from the partial decomposition of dead vegetation
under conditions of high humidity and limited air access (initial stage
of coalification). Only peat used as fuel is included. Its principal use
is as a household fuel.
Patent fuel (hard coal briquettes):
A composition fuel manufactured from coal fines by shaping with the addition
of a binding agent such as pitch.
Lignite briquettes:
A composition fuel manufactured from lignite. The lignite is crushed,
dried and molded under high pressure into an even shaped briquette without
the addition of binders.
Peat briquettes:
A composition fuel manufactured from peat. Raw peat, after crushing and
drying, is molded under high pressure into an even-shaped briquette without
the addition of binders.
Coke:
The solid residue obtained from coal or lignite by heating it to a high
temperature in the absence or near absence of air. It is high in carbon
and low in moisture and volatile matter. Several categories are distinguished:
a) Coke-oven coke - The solid product obtained from carbonization
of coal, principally coking coal, at high temperature. Coke-oven coke
is also called metallurgical coke and is used mainly in the iron and steel
industry. Semi-coke, the solid product obtained from carbonization of
coal at low temperature, is included with coke-oven coke. It is used mainly
as a domestic fuel.
b) Gas coke - A by-product of coal used for the production of gas
works gas in gasworks. Gas coke is mainly used as a domestic fuel.
c) Brown coal coke - A solid product obtained from carbonization
of brown coal briquettes.
Oil shale:
A sedimentary rock containing a high proportion of organic
matter (kerogen), which can be converted to crude oil or gas by heating.
Bituminous sands:
Sands or sandstones containing a high proportion of tarry hydrocarbons,
capable of yielding oil through heating or other extractive processes.
Heavy oils and tars which are so dense and viscous and lacking in primary
energy that they cannot be produced commercially by conventional methods,
that is, by natural flow or pumping, are also included.
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Crude oil:
A mineral oil consisting of a mixture of hydrocarbons of natural origin,
yellow to black in color, of variable density and viscosity. Data in this
category also includes lease or field condensate (separator liquids) which
is recovered from gaseous hydrocarbons in lease separation facilities, as
well as synthetic crude oil, mineral oils extracted from bituminous minerals
such as shales and bituminous sand, and oils from coal liquefaction.
Natural gas liquids (NGL):
Liquid or liquefied hydrocarbons produced in the manufacture, purification
and stabilization of natural gas. NGL's include, but are not limited to,
ethane, propane, butane, pentane, natural gasolene, and plant condensate.
NGL's are either distilled with crude oil in refineries, blended with refined
petroleum products or used directly depending on their characteristics.
Plant condensate:
Liquid hydrocarbons condensed from wet natural gas in natural gas processing
plants. It is used as a petroleum refinery input.
Natural gasolene:
Light spirit extracted from wet natural gas, often in association with crude
petroleum. It is used as a petroleum refinery and petrochemical plant input
and is also used directly for blending with motor spirit without further
processing.
Petroleum products:
Comprise the liquid fuels, lubricant oils and solid and semi solid products
obtained by distillation and cracking of crude petroleum, shale oil, or
semi refined and unfinished petroleum products. As far as possible the series
include fuels consumed in refining, but exclude oil products obtained from
natural gas, coal, lignite and their derivatives.
Aviation gasolene:
Motor spirit prepared especially for aviation piston engines, with an octane
number varying from 80 to 145 RON and a freezing point of -60°C.
Motor gasolene:
Light hydrocarbon oil for use in internal combustion engines such as motor
vehicles, excluding aircraft. It distills between 35°C and 200°C, and is
treated to reach a sufficiently high octane number of generally between
80 and 100 RON. Treatment may be by reforming, blending with an aromatic
fraction, or the addition of benzole or other additives (such as tetraethyl
lead).
Jet fuel:
Consists of gasolene-type jet fuel and kerosene-type jet fuel.
Gasolene-type jet fuel:
All light hydrocarbon oils for use in aviation gas-turbine engines. It distills
between 100°C and 250°C with at least 20% of volume distilling at 143°C.
It is obtained by blending kerosene and gasolene or naphtha in such a way
that the aromatic content does not exceed 25% in volume. Additives are included
to reduce the freezing point to -58°C or lower, and to keep the Reid vapour
pressure between 0.14 and 0.21 kg/cm2.
Kerosene-type jet fuel:
Medium oil for use in aviation gas-turbine engines with the same distillation
characteristics and flash point as kerosene, with a maximum aromatic content
of 20% in volume. It is treated to give a kinematic viscosity of less than
15 cSt at -34°C and a freezing point below -50°C.
Kerosene:
Medium oil distilling between 150°C and 300°C; at least 65% of volume distills
at 250°C. Its specific gravity is roughly 0.80 and its flash point is above
38°C. It is used as an illuminant and as a fuel in certain types of spark-ignition
engines, such as those used for agricultural tractors and stationary engines.
Other names for this product are burning oil, vaporizing oil, power kerosene
and illuminating oil.
Gas-diesel oil (distillate fuel oil):
Heavy oils distilling between 200°C and 380°C, but distilling less than
65% in volume at 250°C, including losses, and 85% or more at 350°C. Its
flash point is always above 50°C and its specific gravity is higher than
0.82. Heavy oils obtained by blending are grouped together with gas oils
on the condition that their kinematic viscosity does not exceed 27.5 cSt
at 38°C. Also included are middle distillates intended for the petrochemical
industry. Gas-diesel oils are used as a fuel for internal combustion in
diesel engines, as a burner fuel in heating installations, such as furnaces,
and for enriching water gas to increase its luminosity. Other names for
this product are diesel fuel, diesel oil, gas oil and solar oil.
Residual fuel oil:
A heavy oil that makes up the distillation residue. It comprises all fuels
(including those obtained by blending) with a kinematic viscosity above
27.5 cSt at 38°C. Its flash point is always above 50°C and its specific
gravity is higher than 0.90. It is commonly used by ships and industrial
large-scale heating installations as a fuel in furnaces or boilers.
Liquefied petroleum gas (LPG):
Hydrocarbons which are gaseous under conditions of normal temperature
and pressure but are liquefied by compression or cooling to facilitate
storage, handling and transportation. They are (i) extracted by stripping
of natural gas at crude petroleum and natural gas sources; (ii) extracted
by stripping of imported natural gas in installations of the importing
country; and (iii) produced both in refineries and outside of refineries
in the course of processing crude petroleum or its derivatives. It comprises
propane (C3H8), butane (C4H10), or a combination of the two. Also included
is ethane (C2H6) from petroleum refineries or natural gas producers' separation
and stabilization plants.
Refinery gas:
Non-condensable gas obtained during distillation of crude oil or treatment
of oil products (e.g. cracking) in refineries. It consists mainly of hydrogen,
methane, ethane and olefins, and is used principally as a refinery fuel.
Refinery gas is also known as still gas.
Feedstocks:
Products or a combination of products derived from crude oil destined
for further processing in the refining industry other than blending. They
are transformed into one or more components and/or finished products.
This definition covers naphtha imported for refinery intake and naphtha
returned from the chemical industry to the refining industry.
Naphtha:
Light or medium oil distilling between 30°C and 210°C, for which there
is no official definition, but which does not meet the standards laid
down for motor spirit. The properties depend upon consumer specification.
The C:H ratio is usually 84:14 or 84:16, with a very low sulphur content.
Naphtha may be further blended or mixed with other materials to make high-grade
motor gasolene or jet fuel, or may be used as a raw material for manufactured
gas. Naphtha is sometimes used as input to feedstocks to make various
kinds of chemical products, or may be used as a solvent.
White spirit/industrial spirit:
A highly refined distillate with a boiling point ranging from 135°C to
200°C, which is used as a paint solvent and for dry-cleaning purposes.
Lubricants:
Viscous, liquid hydrocarbons rich in paraffin waxes, distilling between
380oC and 500oC, obtained by vacuum distillation of oil residues from
atmospheric distillation. Additives may be included to alter their characteristics.
Their main characteristics are: a flash point greater than 125°C; a pour
point between -25°C and +5°C depending on the grade; a strong acid number
(normally 0.5 mg/g); an ash content less than or equal to 0.3%; and a
water content less than or equal to 0.2%. Included are cutting oils, white
oils, insulating oils, spindle oils and lubricating greases.
Bitumen:
Solid or viscous hydrocarbon with a colloidal structure, brown or black
in color, which is obtained as a residue by vacuum distillation of oil
residues from atmospheric distillation. It is sometimes soluble in carbon
bisulphite, non-volatile, thermoplastic (generally between 150°C and 200°C),
often with insulating and adhesive properties. It is used mainly in road
construction. Natural asphalt is excluded.
Petroleum waxes:
Saturated aliphatic hydrocarbons obtained as residues extracted when dewaxing
lubricant oils, with a crystalline structure with C greater than 12. Their
main characteristics are as follows: they are colorless, in most cases
odorless and translucent; they have a melting point above 45°C, a specific
gravity of 0.76 to 0.78 at 80°C, and a kinematic viscosity between 3.7
and 5.5 cSt at 99°C. These waxes are used for candle manufacture, polishes
and waterproofing of containers, wrappings, etc.
Petroleum coke:
A shiny, black solid residue obtained by cracking and carbonization in
furnaces. It consists mainly of carbon (90 to 95%) and generally burns
without leaving any ash. It is used mainly in metallurgical processes.
It excludes those solid residues obtained from carbonization of coal.
Other petroleum products:
Products of petroleum origin (including partially refined products) not
otherwise specified.
Natural gas - Gases consisting mainly of methane
occurring naturally in underground deposits. It includes both non-associated
gas (originating from fields producing only hydrocarbons in gaseous form)
and associated gas (originating from fields producing both liquid and
gaseous hydrocarbons), as well as methane recovered from coal mines and
sewage gas. Production of natural gas refers to dry marketable production,
measured after purification and extraction of natural gas liquids and
sulphur. Extraction losses and the amounts that have been reinjected,
flared, and vented are excluded from the data on production.
Gasworks gas - Gas produced by public utilities or private plants
whose main activity is the production, transport and distribution of such
gas. It includes gas produced by carbonization, by total gasification
with or without enrichment with oil products, by cracking of natural gas,
and by reforming or mixing gases.
Coke oven gas - By product of the carbonization process in the
production of coke in coke ovens.
Blast furnace gas - By product in blast furnaces recovered on
leaving the furnace.
| ELECTRICITY AND OTHER FORMS OF ENERGY |
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Electricity production:
Refers to gross production, which includes the consumption by station
auxiliaries and any losses in the transformers that are considered integral
parts of the station. Included also is total electric energy produced
by pumping installations without deduction of electric energy absorbed
by pumping.
Production data includes Solar, Tide, Wave, Wind, Wastes, Wood and Fuel
cell production when reported.
Public utilities:
Comprise the undertakings whose essential purpose is the production, transmission
and distribution of electric energy, primarily for use by the public.
These may be private companies, co operative organizations, local or regional
authorities, nationalized undertakings or governmental organizations.
Self producers:
include undertakings which, in addition to their main activities, themselves
produce (individually or in combination) electric energy intended, in
whole or in part, to meet their own needs. They may be privately or publicly
owned.
Primary electricity:
Refers to electrical energy of geothermal, hydro, nuclear, tide, wind,
wave/ocean and solar origin. Its production is assessed at the heat value
of electricity (3.6 TJ/million kWh).
Secondary electricity is defined as thermal electricity,
which comprises conventional thermal plants of all types, whether or not
equipped for the combined generation of heat and electric energy. Accordingly,
they include steam operated generating plants, with condensation (with
or without extraction) or with back pressure turbines and plants using
internal combustion engines or gas turbines whether or not these are equipped
for heat recovery.
Net installed capacity is measured at the terminals of the stations,
i.e., after deduction of the power absorbed by the auxiliary installations
and the losses in the station transformers, if any. Data concerning capacity
refer in principle to 31 December of the year under consideration.
Imports and exports:
Refer to the amounts of electric energy transferred to and from the country
concerned, respectively, which are measured at the metering points on
the lines crossing the frontiers. Included are imports and exports of
electric energy made by means of high voltage lines crossing frontiers
as well as imports and exports made by means of low voltage lines for
use in the immediate vicinity of the frontier, if the quantities so transferred
are known.
Heat:
Heat obtained from (a) combined heat and power (CHP) plants generating
electricity and useful heat in a single installation; (b) district heating
(DH) plants and (c) nuclear power plants and geothermal sources. The heat
may be in the form of steam, hot water or hot air.
Uranium (U) production:
Comprises the U content of uranium ores and concentrates intended for
treatment for uranium recovery.
| TRADITIONAL FUELS - Biomass |
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Fuelwood:
All wood in the rough used for fuel purposes. Production data include
the portion used for charcoal production, using a factor of 6 to convert
from a weight basis to the volumetric equivalent (metric tons to cubic
metres) of charcoal.
Bagasse:
The cellulosic residue left after sugar is extracted from sugar cane.
It is often used as a fuel within the sugar milling industry.
Charcoal:
Solid residue, consisting mainly of carbon, obtained by the destructive
distillation of wood in the absence of air.
Alcohol - Ethanol:
(ethyl alcohol) and methanol (methyl alcohol) for use as a fuel. Ethanol
can be produced from sugar, starch and cellulose and is used mainly in
transport (on its own or blended with gasolene). Methanol can be produced
from wood, crop residues, grass, and the like and can be used in internal
combustion engines.
Animal wastes:
Excreta of cattle, horses, pigs, poultry, etc., and (in principle) excreta
of humans, used as a fuel.
Vegetal wastes:
Mainly crop residues (cereal straw from maize, wheat, paddy rice, etc.)
and food processing wastes (rice hulls, coconut husks, ground nut shells,
etc.) used for fuel. Bagasse is excluded.
Municipal wastes:
Consist of products that are combusted directly to produce heat and/or
power and comprise wastes produced by the residential, commercial and
public services sectors that are collected by local authorities for disposal
in a central location. Hospital waste is included in this category.
Industrial wastes:
Consist of solid and liquid products other than solid biomass and
animal products mentioned above (e.g. tires) combusted directly, usually
in specialised plants, to produce heat and/or power.
Other wastes:
Wastes not specifically defined above, such as pulp
and paper wastes.
United Nations Statistics Division - Energy Statistics
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