This topic describes how to configure the impact factors of greenhouse gas (GHG) emissions for emission facilities and activities. You can select impact factors from impact factor databases or manually configure impact factors.
GHG refers to the gases that naturally exist in the atmosphere and that are produced by human activities. GHG can absorb and emit radiation generated by the earth surface, atmosphere, and clouds with wavelengths in the infrared spectrum. The Kyoto Protocol defines seven GHG types: carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O), nitrogen trifluoride (NF3), sulfur hexafluoride (SF6), hydrofluorocarbons (HFCs), and perfluorocarbons (PFCs). The corporate carbon accounting tool of Energy Expert allows you to configure the impact factors of seven GHG types for emission sources and analyze relevant results.
Energy Expert uses the emission factor method to quantify GHG emissions based on the following formula:
CE = Σ ADi × EFij × GWPj
In this formula, CE indicates the total GHG emissions (measured by the CO₂ equivalent, CO₂e) produced by the accounted organization within the accounting period. i indicates the ith emission source. ADi indicates the activity data of the emission source i. EFij indicates the emission factor of the jth GHG of the emission source i. GWPj indicates the global warming potential (GWP) value that the jth GHG can be converted into CO2. The preset GWP values of various GHG types in Energy Expert are obtained from the sixth report of the Intergovernmental Panel on Climate Change (IPCC).
You can configure the impact factors of different GHG types for emission sources, including the emission factor value and GWP value for each GHG type. You can select impact factors from impact factor databases or manually configure impact factors.
Select impact factors from impact factor database
Energy Expert allows you to select impact factors from mainstream emission factor databases in and outside China, including UK Government GHG Conversion Factors for Company Reporting (DEFRA), Ecoinvent, etc.
Click Add Impact Factor in the Facility/activity configuration panel to view and filter impact factors.
By default, Databases related to corporate carbon accounting is selected. You can switch to Databases related to product carbon footprint in the upper-left corner. The differences between the two types of databases lie in the following aspects: Databases related to corporate carbon accounting contain not only the comprehensive emission factor value of GHG for each factor, but also the emission factor values of different GHG types for specific factors. Databases related to product carbon footprint contain only the comprehensive emission factor value of GHG for each factor. The CO2e is used for calculation and analysis.
You can filter impact factors by specifying conditions such as the database, emission category, sub-category, factor name, and factor category. This helps you efficiently find appropriate impact factors.
Find an impact factor and click Details in the Operation column to view the factor details.
Select an impact factor and click Confirm selection to apply the factor to the current emission source.
If an impact factor that you select from databases has the emission factor values of various GHG types, the GHG types and their emission factor values are displayed on the carbon accounting template configuration page. If an impact factor that you select from databases has only the comprehensive emission factor value of GHG, it means that the types of GHG emissions cannot be further divided. In this case, the type of GHG and its emission factor value are displayed on the carbon accounting template configuration page, and GHG is calculated and analyzed as CO2 (GWP = 1). When you select emission factors from databases, the preset GWP values of various GHG types in Energy Expert are used by default. These GWP values are obtained from the sixth report of IPCC and cannot be modified.
Manually configure impact factors
Energy Expert allows you to manually configure impact factors, including the GHG type, emission factor value, and GWP value.
Click Manual Configuration Impact factor in the upper-right corner of the Impact Factor Configuration section.
Select the GHG type that you want to configure from the GHG Type drop-down list. Seven GHG types are available: CO2, CH4, N2O, HFCs, PFCs, SF6, and NF3.
If you want to select multiple GHG types, click Add gas type. You can also find a GHG type and click the Delete icon in the Operation column to remove it.
You can enter an emission factor value for a GHG type in the Emission Factor Value column. You can also click Calculate factor by formula in the Operation column to customize parameters and a formula for calculating the emission factor value of the GHG type. If you select Fixed value as Parameter type, enter the parameter name, parameter value, and parameter unit. If you select Data item as Parameter type, select an existing data item or create a data item. If the formula contains one or more parameters of the data item type, the emission factor value cannot be directly calculated. As a result, a hyphen (-) is displayed in the Emission Factor Value column in the Impact Factor Configuration section.
After you select a GHG type, the preset GWP value in Energy Expert is displayed by default. When you manually configure an impact factor, you can modify the GWP value. Move the pointer over the GWP value and click the Edit icon to modify the GWP value.
