Fuel Calorific Values

The calorific value of a fuel is the quantity of heat produced by its combustion – at constant pressure and under “normal”  (standard) conditions (i.e. to 0oC and under a pressure of 1,013 mbar).

The combustion process generates water vapor and certain techniques may be used to recover the quantity of heat contained in this water vapor by condensing it.

  • Higher Calorific Value (or Gross Calorific Value – GCV, or Higher Heating Value – HHV) – the water of combustion is entirely condensed and that the heat contained in the water vapor is recovered;
  • Lower Calorific Value (or Net Calorific Value – NCV, or Lower Heating Value – LHV) – the products of combustion contains the water vapor and that the heat in the water vapor is not recovered.

Arrow Right   Fuel Calorific Values

Natural gas 12500 kcal/kg
Propane-butane 11950 kcal/kg
Disel 10000 kcal/kg
Fuel oil 9520 kcal/kg
Brown coal 3500 kcal/kg
Woods 2500 kcal/kg
Electricity 860 kcal/kWh

Arrow Right 1 cubic meter of Methane weighs 0.717 kg/m³

Arrow Right   1 kW is obtained from:

0.072 kg natural gas
0,073 kg propane-butane
0,083 kg gasoline
0,085 kg disel
0,092 kg fuel oil
0,124 kg charcoal
0,144 kg coal
0,218 kg brown coal

Arrow Right   Composition of Natural Gas

Methane CH4 70-90%
Ethane C2H6 0-20%
Propane C3H8 Butane C4H10 Carbon Dioxide CO2 0-8%
Oxygen O2 0-0.2%
Nitrogen N2 0-5%
Hydrogen sulphide H2 S 0-5%
Rare gasesA, He, Ne, Xe trace

17 thoughts on “Fuel Calorific Values

  1. Jorge Martins

    Would the Calorific Values presented High or Low? I mean, should they be compared to High Heating Values or to Low Heating Values?

  2. Martin

    I am sorry, but a lot of mistakes in the tables provided.

    First the dimensions: it says that 0.072 kg of NG gives 1 KW; actually this should be 1 kJ or alternatively it could have been 0.072 kg/s (consumption) delivers 1 KW.

    Second, it is unclear what is meant here. I assume we are talking about the caloric value translated into “heat” and not “power”. If power is meant then much more is wrong with the tables. However, if it is combustion value (heat) also the calculation is wrong.

    1 kg of NG is approx. 52000 kJ/kg caloric value which fits with 12500 kcal/kg. Then 0.072 kg of NG gives me 0.072 x 52000 = 3744 kJ -OR- 0.072 kg/s NG gives me 3,744 kW (and not 1 KW as quoted). So either there is a huge mistake, or the KW figure is electricity and inefficiencies/losses of E-generation are taken into account. However, then it does not fit with other fuels quoted.

    So please update your data.


  3. Martin

    further calcls give me:

    1 kWh is 1 KW power during 3600 secs, which is
    1 kJ/s during 3600 secs, which is
    (1/52300) (kJ/s divided by kJ/kg) during 3600 s, which is
    (1/52300) x 3600 kg NG = 0.0688 kg NG, which is close to the 0.072 kg NG per KWh.

    In other words: the second table should be defined as the amount of fuel to generate 1 kWh. But again this is thermal and not yet electricity.


  4. Jayachandran

    The unit in second table is kg/hr.

    Amount of rate of fuel required for generating 1 kW or 1 kJ/sec energy is 0.072 kg/hr considering 95% fuel efficiency.

    0.072 (kg/hr) * 12500 * 4.1868 (kJ/kg) / 3600 = (Approx.) 1 kJ/sec or 1 kW


    It means by burning one molecule of methane produce greater amount of energy then by burning one molecule of Gasoline. Although number of carbons are greater in gasoline then in methane. Also density of gasoline is greater then that of Methane. I am confuse can anyone share the logic and science behind this. I will be grateful.

  6. karl

    can you give energy (calorific values) in kWh?
    it is much easier to compare to everything else. no one uses kcal any longer.
    1 litre or 95 oktane benzin 8,9 kWh
    1 kg natural gas CNG 13,3 kWh, etc.

  7. Gunnar Nybråten

    Re Martins comments
    Yes, the unit for energy is wrong. What is apparently meant is 1 kWh (3.6 MJ)

  8. Yfar

    Please help me
    I want to use Natural gas in place of HFO and I think it is sheaper. Ho much it is cost and what is the current price .

    Can I have an explantation to this and if you have data can you share with me


  9. Philip

    Thanks for the great article. There is couple of factors that decide about smokeless coal value. The sulfur content really doesn’t affect whether the coal is hot or just warm. Unfortunately, there is no information on the calorific value of coal per kg on coal packages. This would be very helpful in identifying the heating power of the coal and thus counting costs. I found a bit information about that on FAQ https://finglasfuels.ie and follow that there is quite detailed report on ec.europa.eu or just simply type “calorific value of coal in kj/kg” in google. It is worth to know I believe.


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