In the ETM the total greenhouse gas emissions for both the present and future in your scenario are calculated. This page contains extra information on the modelling principles behind carbon emissions in the ETM.
The ETM make a distinction between four 'types' of greenhouse gas emissions:
- Energetic CO2 emissions. These emissions are calculated by the ETM based on the energy use in your scenario. In other words, they are the result of the choices made in the Demand and Supply sections of the model.
- Non-energetic CO2 emissions. These emissions are given as an input to the ETM. For the future year, you can make assumptions about the growth or decline of these emissions in the Emissions section of the ETM. There are two exceptions to this category: non-energetic CO2 in the Fertilizer industry and from hydrogen feedstock use (e.g. in the Chemicals industry) are calculated dynamically by the ETM based on energy demand and supply.
- Energetic other greenhouse gas emissions. For example methane and nitrous oxide. These emissions are given as an input to the ETM. For the future year, you can make assumptions about the growth or decline of these emissions in the Emissions section of the ETM. This means that these emissions are not adjusted automatically by the ETM if changes are made to energy supply and demand.
- Non-energetic other greenhouse gas emissions. For example methane and nitrous oxide. These emissions are given as an input to the ETM. For the future year, you can make assumptions about the growth or decline of these emissions in the Emissions section of the ETM.
To calculate the energetic CO2 emissions in your scenario (category 1), the ETM assumes the following principles:
- Emissions are assigned to the sector energy is used in, rather than the location of emissions. This means that emissions related to the production of, for example, electricity are attributed to all sectors using electricity (households, industry etc.) rather than to the power sector. A consequence of this approach is that the ETM by default does take into account emissions of imported energy carriers (imported ammonia, electricity, heat, hydrogen etc.) and does not take into account emissions of exported energy carriers.
Checkout: the 'Emissions from import' infopage which provides more information on this subject.
In a departure from common UNFCCC standards, emissions per sector are calculated based on the primary energy that is used to supply the final energy demand of that sector. This means that any conversion and transportation losses are included in the sector's emissions. For example, transmission losses of the power grid are distributed to the demand sectors relative to their electricity demand. The primary energy demand is multiplied with the emission factor per carrier to obtain the CO2 emissions. More information can be found in the emission factors article.
The ETM follows international conventions regarding the scope of CO2 emissions. More precisely, this means that by default:
LULUCF (Land Use, Land Use Change, and Forestry) emissions are out of scope. For more information on these definitions click here.
Other greenhouse gases and CO2 emissions from non-energetic processes are calculated seperately. These emissions can be adjusted in the Emissions > Greenhouse gases section in the ETM. As stated briefly above, there are exceptions to this:
- The ETM does include the calculation of CO2 emissions resulting from natural gas feedstock in the fertilizer industry. This gas is used in Steam Methane Reformers to produce hydrogen feedstock. As this is closely tied to the energy system and virtually all of this CO2 is emitted, it is included in the ETM.
- The ETM does include the calculation of emissions related to final demand of non-energetic hydrogen and ammonia. Users can make explicit assumptions about how this is produced in the hydrogen and ammonia section. As such, the ETM is able to determine the emissions related to this.