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Appendix C: Energy measurement and conversion factors

Energy is the ability to do work. The International System of Units (SI) unit of energy across all energy types is the Joule (J). It is defined as the amount of work done by a force of one newton exerted over a distance of one metre.

Power is the rate at which work is delivered. The SI unit of power is the watt (W). One watt is equal to one joule per second (1 W = 1 J/sec). Watt is the common unit for electrical power (sometimes expressed as We) although may be used for thermal power (Wt).

Consumption of electric energy is measured in kilowatt-hours (kWh), which is equal to the power in kilowatts (kW) times the time period (hours (h)).

energy (kWh) = power (kW) x time (h)

The average annual energy production or consumption can be expressed in kilowatt-hours per year (kWh/year). For example, a power plant with a capacity of one MW produces 1000 kWh when the plant runs consistently for one hour. If the power plant runs consistently with no downtime for a year (8760 hours), the generator produces 8 760 000 kWh (8 760 MWh) in a year.

Both Joules and Watts are more commonly recorded in multiples.

Units

EJExajoule - 1018 joules
GJGigajoule - 109 joules
GtGigatonne - 109 tonnes
GWGigawatt - 109 watts
ktKilotonne - thousand (103) tonnes
kWKilowatt - thousand (103) watts
kWhKilowatt-hours - thousand (103) watt-hours
MLMegalitre - million (106) litres
mmbblMillion (106) barrels
MtMillion (106) tonnes
MWMegawatts - 106 watts
MWhMegawatt-hours - 106 watt-hours
PJPetajoules - 1015 joules
tcfTrillion (1012) cubic feet
TJTerajoules - 1012 joules
TWhTerawatt-hours - 1012 watt-hours

Decimal numbering system

Multiples of energy measurements in Australia are expressed in standard international decimal classification terms:

MultipleScientific exp.TermAbbreviation
Thousand103Kilok
Million106MegaM
Billion109GigaG
Trillion1012TeraT
Quadrillion1015PetaP
Quintillion1018ExaE

Energy measurement

Energy production and consumption are typically reported in the SI unit as petajoules (PJ) as used here but in some cases are reported in barrels of oil equivalent (BOE) and million tonnes of oil equivalent (MTOE).

Individual energy resources are commonly reported according to prevailing industry conventions. Petroleum is reported by volume and weight according to either the SI or the United States system as used by the American Petroleum Institute.

In this report energy is reported in SI units (PJ) with the conventional volume or weight equivalent terms widely in use in industry in parentheses.

Energy resourceMeasureAbbreviation
Oil and condensateProduction, reserves: Litres (usually millions or billions)or barrels (usually thousands or millions)
Refinery throughput/capacity: Litres (usually thousands or millions) or barrels per day (usually thousands or millions)
L, ML, GL
bbl, kbbl, mmbbl
ML, GL per day
bd, kbd, mmbd
Natural gasCubic feet (usually billions or trillions)Or cubic metres (usually millions or billions of cubic metres)bcf, tcf
m3, mcm, bcm
LNGTonnes (usually millions)
Production rate: Million tonnes per year
t, Mt
Mtpa
LPGLitres (usually megalitres) or barrels (usually millions)L, ML
bbl, mmbl
CoalTonnes (usually millions or billions)
Production rate: tonnes per year (usually kilotonnesor million tonnes per year)
t, Mt, Gt
tpa, Mtpa
UraniumTonnes (usually kilotonnes) of uranium or of uranium oxidet U; kt U
t U3O8; kt U3O8
ElectricityCapacity: watts, kilowatts, etc
Production or use: watt-hours, kilowatt-hours, etc
W, kW, MW
Wh, kWh, MWh
Bioenergy
  • bagasse, biomass
Tonnes (or thousands of tonnes)t, kt

Fuel-specific to standard unit conversion factors

Oil and condensate1 barrel=158.987 litres
1 gigalitre (GL)=6.2898 million barrels
1 tonne (t)=1250 litres (indigenous)/
1160 litres (imported)
Ethanol1 tonne=1266 litres
Methanol1 tonne=1263 litres
LPG
  • average
1 tonne=1760 - 1960 litres
  • naturally occurring
1 tonne=1866 litres
Natural gas1 cubic metre (m3)=35.315 cubic feet (cf)
Liquefied natural gas1 tonne=2174 litres
Electricity1 kilowatt-hour (kWh)=3.6 megajoules (MJ)

Energy content conversion factors

The energy content of individual resources may vary, depending on the source, the quality of the resource, impurities content, extent of pre-processing, technologies used, and so on. The following table provides a range of measured energy contents and, where appropriate, the accepted average conversion factor.

a) Gaseous fuels

PJ/bcfMJ/m3
Natural gas
  • Victoria
1.098738.8
  • Queensland
1.118539.5
  • Western Australia
1.175141.5
  • South Australia, New South Wales
1.084538.3
  • Nothern Territory
1.146840.5
  • Average
1.628257.5
Ethane (average)1.628257.5
Town gas
  • synthetic natural gas
1.104339.0
  • other town gas
0.707925.0
  • Coke oven gas
0.512518.1
  • Blast furnace gas
0.11334.0

b) Liquid fuels

PJ/mmbblBy volume
MJ/L
By weight
GJ/t
Crude oil and condensate
  • indigenous (average)
5.8837.046.3
  • imports (average)
6.1538.744.9
LPG
  • propane
4.05 25.5 49.6
  • butane
4.4728.1 49.1
  • mixture
4.0925.7 49.6
  • naturally occurring (average)
4.2126.5 49.4
Other
  • Liquefied natural gas (North West Shelf)
3.97 25.0 54.4
Naphtha4.9931.448.1
Ethanol3.7223.429.6
Methanol2.4815.619.7

c) Solid fuels

GJ/t
Black coal
New South Wales
  • Exports - metallurgical coal
29.0
  • Exports - thermal coal
27.0
  • Electricity generation
23.4
  • Other
23.9 - 30.0
Queensland
  • Exports - metallurgical coal
30.0
  • Exports - thermal coal
27.0
  • Electricity generation
23.4
  • Other
23.0
Western Australia
  • Thermal coal
19.7
Tasmania
  • Thermal coal
22.8
Lignite (Brown Coal)
Victoria9.8
  • Briquettes
22.1
South Australia15.2
Uranium*
  • Metal (U)
560 000
  • Uranium Oxide (U3O8)
470 000
Other
  • Coke
27.0
  • Wood (dry)
16.2
  • Bagasse
9.6

* The usable energy content of uranium metal (U) is 0.56 petajoules per tonne, and that of uranium oxide (U3O8) is 0.47 petajoules per tonne. The oxide contains 84.8 per cent of the metal by weight
Source: BREE; Geoscience Australia