View the common conversion factors for energy use in Ireland.

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Download all calorific values, emission factors, densities and primary energy factors for 2001 to present.

SEAI conversion and emission factors

Energy units

Energy is delivered in many different fuels and sources and can be expressed in terms of volume, mass, energy or emissions. Using the conversion factors below, it is possible to express each fuel or energy source in common units of energy or emissions so that they can be compared and aggregated.

Energy unit types

  • Joule (J): Joule is the international unit of energy
  • Kilowatt hour (kWh): This is the conventional unit of energy that electricity is measured by and charged for commercially.
  • Tonne of oil equivalent (toe): This is a conventional standardised unit of energy (41.868 GJ), and is defined on the basis of a tonne of typical oil having a net calorific value of 41,868 kJ/kg. A related unit is the kilogram of oil equivalent (kgoe), where 1,000 kgoe = 1 toe.

Energy unit conversion

TotoeMWhGJ
From Multiply by    
toe 1 11.63 41.868
MWh 0.086 1 3.6
GJ 0.02388 0.2778 1

Energy content

Conversions of fuel quantities -- from physical units to energy units -- require conversion factors expressing the heat obtainable from one fuel unit. Conversion factors are termed the "calorific value" or "heating value" of fuels. Definitions of energy units (toe and J) appear above, while the description of net calorific values (NCV) appears below the table. Unless otherwise stated, all values are NCV.

Liquidtoe/tMJ/kgMJ/lNote
Petroleum        
Crude oil 1.023 42.81 40.13  
Gasoline / petrol (100% petroleum) 1.065 44.59 33.03  
Kerosene 1.056 44.20 35.36  
Jet Kerosene 1.053 44.10 35.28  
Diesel / gasoil (100% petroleum) 1.034 43.31 36.61  
Residual fuel oil / fuel oil 0.985 41.24 39.09  
LPG 1.126 47.16 24.62 Assumes 70% propane & 30% butane by mass
         
Biofuel / bioliquid        
Bioethanol 0.633 26.49 21.20  
Biodiesel ME 0.890 37.27 32.79 Methyl ester
Biodiesel HVO 1.051 44.00 37.23 Hydrotreated vegetable oil
Biodiesel CHVO 1.027 43.00 36.38 Co-processed hydrotreated vegetable oil
Biopropane 1.099 46.00 24.00  
Biojet HVO 1.051 44.00 35.20 Hydrotreated vegetable oil (jet fuel)
         
Blended petroleum & biofuel        
Road diesel (avg. biofuel content) 1.025 42.91 36.37 Average diesel-biofuel blend in 2023 (provisional)
Road petrol (avg. biofuel content) 1.035 43.34 32.26 Average petrol-biofuel blend in 2023 (provisional)
Solidtoe/tMJ/kgNote
Fossil fuel      
Petroleum coke 0.766 32.09 Updated for 2023
Bituminous coal 0.665 27.84  
Anthracite 0.665 27.84  
Lignite 0.473 19.82  
Milled peat 0.130 5.43 Updated for 2023
Sod peat 0.313 13.10  
Peat briquettes 0.443 18.55  
       
Biomass      
Wood pellets & briquettes 0.413 17.28  
Wood logs & chips 0.313 13.11 Assumes 25% moisture content
GasMJ/m3Note
Natural gas (GCV) 39.55 Gross calorific value for 2023
Natural gas (NCV) 35.67 Net calorific value for 2023

Gross calorific value (GCV) is determined by bringing all the products of combustion back to the original pre-combustion temperature, in particular condensing any water vapour produced.  Net calorific value (NCV) is determined by subtracting the heat of vaporisation of the water vapour from the higher heating value.  Since the NCV represents the amount of actual usable energy, we adopted NCVs into the methodology for Ireland’s Energy Balance. The differences between net and gross calorific values are typically about 5% to 6% of the gross value for solid and liquid fuels, and about 10% for natural gas.

Source: European Commission (2019) Energy balance guide link.

Emission factors for fuels

The table below shows emission factors for CO2 produced from combustion of fuels. Definitions of energy units (kWh) and net calorific values (NCV) appear above. These emission factors include only direct CO2 emissions from combustion of fuels and do not include indirect or upstream emissions, such as those from extraction, cultivation, transportation or processing of fuels.

These emission factors are for statistical purposes, such as calculating direct energy-related emissions on a sectoral and national level. The factors are not suitable for use under frameworks that are based on CO2 equivalent of primary energy or life-cycle emissions: Energy Performance of Buildings Directive (EPBD); BER calculations; Public Sector Monitoring and Report; and greenhouse gas saving criteria under the Renewable Energy Directive. Factors to be used under the EPBD calculation framework are published separately under the BER Calculation methodologies.

SEAI does not currently provide emission factors for CH4 and N2O produced from combustion and recommends consulting the EPA's National Inventory Submissions for details on sector-specific factors for CH4 and N2O.

Values for petroleum coke, milled peat, natural gas, electricity, and blended petroleum & biofuel change annually. Unless otherwise stated, all values are calculated based on NCV.

Biomass fuels

The net emission of CO2 from the combustion of biogenic carbon in sustainable biomass fuel (incl. solid biomass, biofuel, bioliquid and biogas) is considered to be zero, as it is assumed that the biomass itself absorbs an equal amount of CO2 during growth as is emitted during combustion. Where biomass fuel is not sustainably produced, CO2 emissions from combustion should be counted. This is consistent with guidelines for greenhouse gas reporting, such as the IPCC 2006 Guideline for National Greeenhouse Gas Inventories & 2019 refinement and EU Emission Trading System.

LiquidgCO2/kWhgCO2/MJkgCO2/kgkgCO2/lNote
Petroleum          
Crude oil 264.0 73.33 3.140 2.943  
Gasoline / petrol (100% petroleum) 251.9 69.96 3.119 2.311  
Kerosene 257.0 71.39 3.155 2.524  
Jet Kerosene 257.0 71.39 3.148 2.519  
Diesel / gasoil (100% petroleum) 263.9 73.30 3.174 2.683  
Residual fuel oil / fuel oil 273.6 76.01 3.134 2.951  
LPG 229.3 63.69 3.003 1.568 Assumes 70% propane & 30% butane by mass
           
Biofuel / bioliquid          
Bioethanol - - - - See note above on biomass fuels
Biodiesel ME - - - - See note above on biomass fuels
Biodiesel HVO - - - - See note above on biomass fuels
Biodiesel CHVO - - - - See note above on biomass fuels
Biopropane - - - - See note above on biomass fuels
Biojet HVO - - - - See note above on biomass fuels
           
Blended petroleum & biofuel  

 

     

Road diesel (avg. biofuel content)

241.0

66.95

2.873

2.435

Average diesel-biofuel blend in 2023 (provisional)

Road petrol (avg. biofuel content)

241.2

66.99

2.904

2.162

Average petrol-biofuel blend in 2023 (provisional)

SolidgCO2/kWhgCO2/MJkgCO2/kgNote
Fossil fuel        
Petroleum coke 345.0 95.83 3.075 Provisional value for 2023
Bituminous coal 340.6 94.60 2.634  
Anthracite 353.9 98.30 2.737  
Lignite 363.6 101.00 2.001  
Milled peat 475.6 132.12 0.717 Provisional value for 2023
Sod peat 374.4 104.00 1.363  
Peat briquettes 355.9 98.86 1.834  
         
Biomass        
Wood pellets & briquettes - - - See note above on biomass fuels
Wood logs & chips - - - See note above on biomass fuels
GasgCO2/kWhgCO2/MJkgCO2/m3Note
Natural gas (GCV) 184.0 51.10 2.021 2023 values on GCV basis
Natural gas (NCV) 204.0 56.66 2.021 2023 values on NCV basis

Emission factors for electricity

The 'electricity consumption' factor published below includes scope 2 emissions (as defined in GHG Protocol Corporate Accounting and Reporting Standard) from electricity generation, and scope 3 emissions from transmission & distribution losses, and own-use of electricity at plants. SEAI does not currently publish 'well to tank' factors for electricity, which account for scope 3 emissions from extraction, refining and transportation of fuels used for electricity generation.

Electricity 2023gCO2/kWhgCO2/MJNote
Electricity consumption 254.8 70.77

- 2023 provisional value

- CO2 per unit of electricity consumed

- Total CO2 from electricity generation / total final consumption of electricity

- Use this factor to calculate CO2 for electricity consumption including generation, transmission and distribution losses, and own-use of electricity in power plants (scope 2 and 3 under the GHG Protocol).

Electricity generation 229.9 63.85

- 2023 provisional value

- CO2 per unit of electricity generated

- Total CO2 from electricity generation / gross electricity production (incl. net imports)

- Use this factor to calculate CO2 for electricity generation only (scope 2 under the GHG Protocol).

Fuel densities

Conversion from volume (litres) to mass (tonnes) for liquid fuels requires the densities or specific volumes of the liquids. The most common fuels are shown here.

Liquid Density [kg/m3] Specific volume [l/t] Note
Petroleum      
Crude oil 937 1,067  
Gasoline / petrol (100% petroleum) 741 1,350  
Kerosene 800 1,250  
Jet Kerosene 800 1,250  
Diesel / gasoil (100% petroleum) 845 1,183  
Residual fuel oil / fuel oil 942 1,062  
LPG 522 1,915 Assumes 70% propane & 30% butane by mass
       
Biofuel / bioliquid      
Bioethanol 800 1,250  
Biodiesel ME 880 1,136 Methyl ester
Biodiesel HVO 846 1,182 Hydrotreated vegetable oil
Biodiesel CHVO 846 1,182 Co-processed hydrotreated vegetable oil
Biopropane 522 1,917  
Biojet HVO 800 1,250

Hydrotreated vegetable oil (jet fuel)

       
Blended petroleum & biofuel      
Road diesel (avg. biofuel content) 848 1,180  

Average diesel-biofuel blend in 2023 (provisional)

Road petrol (avg. biofuel content) 744 1,343  

Average petrol-biofuel blend in 2023 (provisional)

Primary energy conversion factors

Energy consumption can be expressed as total final consumption (TFC) or total primary energy requirement (TPER). TPER accounts for the energy that is consumed and/or lost in transformation, transmission and distribution processes.

TPER can be calculated by applying primary energy (PE) converion factors, which vary by fuel type, to TFC values. The table below shows the latest PE factors. Historic factors can be found in the SEAI conversion and emission factors spreadsheet. With the exception of the PE factor for electricity, all of the factors below are default values, which provide an approximation of primary energy requirement for each fuel. The PE factor for electricity is calculated based on the primary energy inputs to electrical power generation during the year.

LiquidPE factor [-]Note
Petroleum    
Crude oil -  
Gasoline / petrol (100% petroleum) 1.1  
Kerosene 1.1  
Jet Kerosene 1.1  
Diesel / gasoil (100% petroleum) 1.1  
Residual fuel oil / fuel oil 1.1  
LPG 1.1  
     
Biofuel / bioliquid    
Bioethanol 1.1  
Biodiesel ME 1.1 Methyl ester
Biodiesel HVO 1.1 Hydrotreated vegetable oil
Biodiesel CHVO 1.1 Co-processed hydrotreated vegetable oil
Biopropane 1.1  
Biojet HVO 1.1 Hydrotreated vegetable oil (jet fuel)
     
Blended petroleum & biofuel    
Road diesel (avg. biofuel content) 1.1  
Road petrol (avg. biofuel content) 1.1  
SolidPE factor [-]Note
Fossil fuel    
Petroleum coke 1.1  
Bituminous coal 1.1  
Anthracite 1.1  
Lignite 1.1  
Milled peat 1.1  
Sod peat 1.1  
Peat briquettes 1.1  
     
Biomass    
Wood pellets & briquettes 1.1  
Wood logs & chips 1.1  
GasPE factor [-]Note
Natural gas (GCV) 1.1  
Natural gas (NCV) 1.1  
Electricity 2023PE factor [-]Note
Electricity consumption 1.888

- 2023 provisional value

- Primary energy input per unit of available final energy consumption.

- Electricity imports are not included in the calculation of this factor.

Electricity generation 1.706

- 2023 provisional value

- Primary energy input per unit of electricity generated, before subtracting own use of electricity in power plants, and transmission & distribution losses.

- Electricity imports are not included in the calculation of this factor.