This methodology represents carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) emissions associated with the stationary combustion of fuels. The data and calculation methodology is sourced from the Greenhouse Gas Protocol (GHGP), and consolidates data from their worksheet tools GHG emissions from stationary combustion, version 4.0, CO2 emissions from the production of iron and steel, version 2.0 and GHG emissions from pulp and paper mills, version 1.3.
These datasets are in-turn derived from the 2006 IPCC Guidelines for National Greenhouse Gas Inventories, and specifically Volume 2, Chapter 1 - Introduction and Volume 2, Chapter 2 - Stationary Combustion.
The calculations provided within this category represent the Tier 1 approaches of both the IPCC and the US Environmental Protection Agency mandatory greenhouse gas reporting advice.
The emissions methodology is based upon emissions factors which describe the rate at which greenhouse gas emissions are produced during fuel combustion in relation to the energy yielded by the fuel. These emissions factors are expressed in terms of kg per TJ, and are based on the net energy content of fuels (referred to as the net calorific content or the lower heating value). Emissions - expressed in terms of mass (e.g. kg) - are calculated by multiplying these factors by the quantity of energy consumed.
The methodology also includes additional conversion factors which provide the flexibility of calculating via fuel mass or volume, and on the basis energy consumed according to the gross calorific value measure of fuel energy content.
CO2 emissions associated with the stationary combustion of fuel are primarily related to the concentration of carbon within the fuel. Therefore, CO2 emissions vary between fuels types according to their different molecular composition. CH4 and N2O emissions, on the other hand, vary between specific combustion contexts. As such, this methodology provides emissions and conversion factors for 532 distinct combustion scenarios differentiated by fuel type (e.g. blast furnace gas, crude oil, jet gasoline) and combustion context (e.g. energy, construction, forestry).
Each scenario is represented by several data values:
- CO2 emissions factor - used to convert net energy consumption into an emissions quantity
- CH4 emissions factor - used to convert net energy consumption into an emissions quantity
- N2O emissions factor - used to convert net energy consumption into an emissions quantity
- Lower heating value - used to convert fuel mass into net energy consumption
- Lower to higher heating value conversion factor - used to convert gross energy consumption in net energy consumption
- Fuel density - used to convert fuel volumes into fuel mass
Activity data required
Greenhouse gas emissions are directly proportionate to the quantity of fuel consumed. This can be specified in terms of either energy, mass or volume.
Calculation and results
Greenhouse gas emissions are calculated by converting any mass or volume or gross energy quantities into the corresponding quantity of net energy for the given fuel and then applying the gas-specific emissions factors. CH4 and N2O emissions are additionally converted to CO2e using the respecitive GWP's. Four emissions quantities can be calculated, representing CO2, CH4, N2O, and CO2e.
This emissions calculated by this methodology represent those attributable to the specified quantity of fuel combusted.
Higher and lower heating values
Note that switching between LHV and HHV bases for the specification of fuel quantity is only valid when specifying fuel quantity in terms of energy.
Custom emissions factors
CO2 emission factors for butane and propane are not specified in the 2006 IPCC Guidelines for National Greenhouse Gas Inventories. In these cases, values are calculated following this method, recommended by the Greenhouse Gas Protocol.
The Greenhouse Gas Protocol uses Gas/Diesel oil and Distillate fuel synonymously across different worksheets. These have been standardised as Gas/Diesel oil within AMEE.