Secondary Energy production includes a number of subcategories, the most important of which is electricity generation. in addition, liquids, gases, solids, heat, hydrogen exist. Given that not all of the associated conversion technologies are covered in all models, but some more aggregate representation may be used (e.g., non-electric energy), a category Other Carrier has been introduced under which such aggregates that do not match the other categories should be reported.
A reporting difference across models that is frequently coming up is the allocation of solid biomass, including municipal solid waste (MSW), for electricity generation. Whereas in IEA energy statistics the renewable part of MSW is broken out and can be aggregated with other solid biomass, in many models the allocation is different (e.g., MSW is lumped with coal). The allocation used in the reporting should be documented by making use of the comments tab.
Secondary Energy[|Secondary Energy Carrier][|Source] , where �Secondary Energy Carrier� is defined at a relatively high level of aggregation (Solids, Liquids, Gases, Electricity, Heat, Hydrogen, Other) and can be further detailed in a second hierarchy level if necessary (e.g., Solids|Coke). This second hierarchy level should only be used if the combination of �Secondary Energy Carrier� and �Source� are not sufficient to unambiguously define the product (e.g., Liquids|Oil defined unambiguously that the liquid secondary energy carrier is a �Petroleum Product�, so Liquids|Petroleum Products|Oil should be avoided while Liquids|Diesel|Oil would include additional information that cannot be derived from the combination of Liquids and Oil). As in the Primary Energy category, �Source� can be supplemented with technology or process information (e.g., �w/ CCS�).
The structure of the secondary energy variables is illustrated in Figure 1. The highest level variable Secondary Energy is the sum of all of the sub-variables and is mostly used for checking the consistency of the reporting.