Are models suitable for determining ILUC factors?

Models of limited value to determine indirect land use change factors for biofuels

This paper presents a survey of a series of (specific versions of) models and their results, which may potentially be suitable for analysing indirect land use change emissions from the cultivation of biofuels. The present sustainability criteria of the European Union for biofuels include minimum values for reducing greenhouse gas emissions. These reductions are based on a greenhouse gas balance which includes all the steps in the production chain for biofuels. Indirect emissions, however, are not included. One of the outcomes of the political debate surrounding the indirect impact of biofuels is an exploration of the use of emission factors in greenhouse gas balances to take into account the emissions caused by indirect land-use change (an ILUC factor). Analysis using models is one way to derive such factors.

Inclusion of physical land use in world regions is essential

To derive the ILUC factor (or factors) the model needs to take into account the interaction between a new biofuel production chain and the dynamic global system. An ILUC factor is a characteristic of this interaction itself and not of the biofuel, and it varies in time. Other essential aspects to be included in the model are physical land use in all world regions, the impact of by-products (feed) and the consideration of agricultural intensification, agricultural area expansion or change in consumption. Although a range of models includes these aspects, their response to intensification, expansion and consumption change still varies widely.

There are various reasons for this variability:

• The models currently used differ in the way area and intensification changes are implemented;
• The set up of the reference determines the demand for agricultural products and thus agricultural area in the reference. This influences the balance between expansion, intensification and consumption.

The brief report ‘Are models suitable for determining ILUC factors? is a further elaboration of the report ‘Identifying the indirect effects of bio-energy production’, published earlier.

More information on indirect effects:

• Identifying the indirect effects of bio-energy production
• Exploring bioenergy’s indirect effects – economic modelling approaches (PDF 0,4 MB)