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Appendix 3 – Data and calculations for removals from methanol: production formula

Data

Calculations are based on specification natural gas, which has the properties outlined in Table 5 of Appendix 1.

  • Oxidation factor – 0.995

  • Emissions factor for CO2 only (based on complete oxidation) – 0.05355779 tCO2-e/GJ

  • Emissions factor CH4 – 0.0000273 tCO2-e/GJ

  • Emissions factor for N2O – 0.000031 tCO2-e/GJ

  • Total emissions factor – 0.05335 tCO2-e/GJ

Methanol is 37.5% carbon by weight.

Calculations

  1. The quantity of removals is determined by the number of gigajoules (GJ) of specification natural gas used, multiplied by the total emissions factor for specification natural gas:

    Removals (tCO2-e) = GJ Gas x EF
  2. The number of GJ of specification natural gas used is determined by the quantity of carbon in methanol (t), multiplied by the number of GJ per tonne of carbon in specification natural gas:
    GJ Gas = Carbon in Methanol (t) x GJ / Carbon in Gas (t)
  3. The quantity of carbon in methanol is determined by the quantity of methanol, multiplied by 0.375:

    Carbon in Methanol (t) = Methanol (t) x 0.375
  4. The number of GJ per tonne of carbon in specification natural gas is determined by dividing 1 GJ of specification natural gas by the quantity of carbon in 1 GJ of specification natural gas (t).

    GJ / Carbon in Gas (t) = 1 / Carbon in 1 GJ Gas
  5. The quantity of carbon in 1 GJ of specification natural gas is determined by the emissions factor for CO2 only (based on complete oxidation) for specification natural gas, multiplied by the proportion of carbon in CO2:

    Carbon in 1 GJ Gas = EF (CO2 only) x Carbon in CO2
      = 0.05355779 x 12/44
      = 0.01460667
  6. Therefore, the number of GJ per tonne of carbon in specification natural gas:

    GJ Gas / Carbon in Gas (t) = 1 / 0.01460667
      = 68.4618739247
  7. Therefore, the number of GJ of specification natural gas used:

    GJ Gas = Carbon in Methanol (t) x GJ Gas / Carbon in Gas (t)
      = Methanol (t) x 0.375 x 68.4618739247
      = Methanol (t) x 25.6732027217
  8. Therefore, the quantity of removals (tCO2-e):

    Removals (tCO2-e) = GJ Gas x EF
      = Methanol (t) x 25.6732027217 x 0.05335
      = Methanol (t) x 1.3696653652
      = Methanol (t) x 1.37 (rounded)