The GCAM Land Model

This page provides more detailed explanations of the descriptions provided in the inputs to supply and inputs to demand modeling pages.

Mapping the IEA Energy Balances

The IEA Energy Balances (IEA 2019) are a comprehensive set of country-level statistics of energy production, transformation, and use that is the primary source of most calibration information in GCAM. However, the data product itself is somewhat complex, and the mappings from the IEA’s categories to GCAM’s sectors and fuels are not obvious. This section is intended to provide an overview description of the data processing with some detailed tables. It does not define the categories within the IEA data; interested readers are instead referred to the documentation (IEA 2011).

Processing the IEA Data

First, the three composite regions in the IEA Energy Balances (Other Africa, Other Asia, Other Non-OECD Americas) are downscaled to the country level on the basis of population, according to the IEA’s reported country-to-region mapping. This is necessary for the construction of several GCAM regions. Several minor modifications to the dataset are made where thermodynamically impossible conversions were found (e.g., non-zero electricity generation with zero input fuel) that would otherwise result in errors in GCAM. Once the cleaned and country-level dataset is produced, the mappings from the IEA’s categories to GCAM’s categories are used to aggregate the entire dataset by GCAM regions and sectors. The detailed mappings are shown in Table 3 and Table 4, and described further below.

Resolving primary energy balances

In the IEA Energy Balances, the following identity holds for any country and primary fuel:

In GCAM, stock changes and statistical differences are not represented, so globally, the sum of consumption must equal the sum of production, and within any region the sum of production and net trade must be equal to consumption. This is resolved by using the consumption data as reported, and scaling the production data so that the global totals are equal. Net trade in each region is then the difference between the reported consumption and the derived, scaled production.

Resolving secondary energy balances

Similar identities can be constructed for each secondary fuel, wherein the production in the equation above would be replaced by the output of the relevant energy transformation sector(s). Because net stock changes and statistical differences are not modeled for any fuel in GCAM, the data can not be used exactly as reported, and the strategies for addressing these “flows” differ by fuel.

For electricity, the fuel inputs to power plants, electricity generation by power plants, own use of electricity, and distribution losses of electricity are used exactly as reported in each region. The consumption by end use sectors (buildings, industry, and transportation) are scaled to match the generation minus own use and losses. As such, any statistical differences are effectively distributed to the end use sectors.

A similar approach is taken for district heat, in the regions where it is considered as a fuel. In most regions, district heat used by end-use sectors is simply represented by adding the reported fuel inputs to district heating systems to the final energy consumption quantities of the end use sectors. However in regions with significant usage of district services, documented in district heat, the estimates of fuel inputs to the district heat plants are used as reported. Heat outputs are derived using exogenous input-output coefficients, and apportioned to end-use sectors according to relative shares of reported heat consumption.

For refined liquid fuels, the end-use consumption estimates by buildings, industry, and transportation are used as reported. Gross energy consumption quantities at petroleum refineries are also used exactly as reported, so any statistical differences or stock changes in the secondary fuels are effectively assigned to the input-output coefficients of the refineries in the historical years.

The remaining fuels used by end-use consumers (coal, natural gas, and biomass) are primary fuels, whose statistical differences are assigned to the production and trade quantities as described above.

Resolving final energy consumption

This section documents the processing of data from the IEA Energy Balances to GCAM’s “aggregate” final energy consumers: residential, commercial, industrial energy use, industrial feedstocks, and the following transportation modes: air, rail, road, and domestic and international ship. Further processing of the data to the more detailed end-use sectors, services, and technologies in GCAM is documented in buildings, industry, and transportation.

Detailed mappings of products and flows

The tables below show the mappings from the IEA’s “flows” to GCAM’s sectors, and from the IEA’s “products” to GCAM’s fuels. Exceptions to simple one-to-one mappings are noted below the tables.

Table 3: Mapping from IEA flows to GCAM sectors (and subsectors where appropriate)

Table 4: Mapping from the IEA fuels to GCAM fuels

Exceptions to one-to-one mapping from the categories in the IEA Energy Balances are noted here:

• Gas works: Energy inputs and outputs from gas works are only assigned to the coal gasification subsector of gas processing when the input fuel is coal. Otherwise, energy consumed here is mapped to “industrial energy use”, and energy produced is simply added to the primary supply of natural gas.
• Losses: electricity is assigned to “elect_td_XXX”; gas is assigned to “gas pipeline”, and the remainder of the fuels are assigned to “industrial energy use”.
• Pipeline transport: natural gas is assigned to “gas pipeline”, and all other fuels are assigned to “industrial energy use”.
• Primary solid biomass: this is normally mapped to “biomass”, except when consumed by the residential sector in a region where traditional biomass is modeled as a commodity, in which case it is assigned to “traditional biomass”.
• Own use in electricity, CHP and heat plants: Electricity is mapped to “electricity_net_ownuse” and all other fuels are mapped to “industrial energy use”.
• Other liquid biofuels: normally these are mapped to “biomass”, but when consumed by the transportation road flow, they are assigned to “refined liquids”, and for production purposes are assigned to the “refining/biomass liquids/ethanol” technology in each region.
• Petroleum refineries: electricity, gas, and oil inputs are mapped to the refining sector, oil refining technology. However all other inputs (e.g., coal, district heat) are assigned to “industrial energy use.”
• Transportation sector consumption of primary biomass commodities and heat are not considered.

References

[IEA 2011] International Energy Agency, 2011, Energy Balances of OECD Countries: Documentation for Beyond 2020 Files, International Energy Agency, Paris, France. Link

[IEA 2019] International Energy Agency, 2019, Energy Balances of OECD Countries 1960-2017 and Energy Balances of Non-OECD Countries 1971-2017, International Energy Agency, Paris, France.