A Scenario Model for the Generation of Waste

6. Conclusions

The model developed is a simple scenario model linking the generation of waste to economic activities described by the macroeconomic model ADAM. The waste model converts forecasts for the economic development to scenarios for waste generation. Given alternative economic developments, the model may be used to analyse how the economy affects waste generation.

The coupling to economic activities is performed at a detailed level and it is therefore possible to obtain some information about the specific content of the waste. Indicating which economic activities are responsible for the generation of waste, the coupling should be more precise than simple coupling at an aggregated level.

With respect to performance, the present model and a simple model coupled at an aggregated level give almost identical descriptions of the aggregated development over the observation period (the years 1994 to 1996). The point, however, is that with respect to aggregated waste generation, the composition of production and consumption has not changed significantly from 1994 to 1996. Still, the present model has the advantage of being able to capture such changes.

Another conclusion is that the actual development from 1994 to 1996 is not fully explicable by the model. Waste coefficients have changed due to legislation, enlarged collection schemes etc. In addition, the coverage of the waste statistics has improved. For forecasting purposes this implies that a baseline scenario assuming constant waste coefficients is only a starting point. This will have to be supplemented with evaluations of how coefficients may change. Moreover, with respect to individual waste fractions, one has to consider how alternative collection schemes may convert waste from one fraction to another.

The general conclusion from the baseline scenario and sensitivity analyses is that assuming constant waste coefficients, the amount of waste follows the economic development. Changes in the composition of consumption and production may change the proportionality at the aggregated level, however. In addition, some fractions (e.g. garden waste) are not coupled to economic development and for others technological changes are expected to reduce the amount of waste.

Finally, in applying the model it should be kept in mind that this is an initial model based on the limited data available, and that the coupling to economic activities is subject to some uncertainty. The data available are insufficient for establishing firm relationships between the amount of waste and detailed economic variables. However, the coupling used is our best evaluation of how amounts of waste and economic activities are related.