A Scenario Model for the Generation of Waste

5. Baseline scenario and sensitivity analyses

To illustrate the workings of the model, a baseline scenario and a few sensitivity analyses are shown. Sensitivity analyses using alternative ADAM forecasts are not shown, although this is facilitated by the coupling to ADAM, and the model may be used to analyse how alternative economic developments and policies affect waste generation.

Based on the economic forecasts used for the 1997 public budget (Ministry of Finance 1997 Medium Term Economic Survey) and the energy forecast in the Government’s energy action plan, Energy21, the amount of waste has been calculated for the period 1996 to 2005. Aggregated economic development is shown in Table 5.1. In general, all economic activities are assumed to increase by about 25% from 1996 to 2005, with industrial production growing slightly less and that within the trade and service sector slightly more.

In Energy21, coal consumption by power plants is expected to decrease to about 1/3 of that in 1996. As seen in Table 5.2, this implies an equally considerable decrease in generation of residuals from coal-fired power plants. Part of the decrease is due to extraordinarily large electricity production and coal consumption in 1996, and to the a net export of electricity in 1996. According to Energy 21, however coal consumption by power plants will decrease about 50% from 1997 to 2005 due to a switch in fuel.

Table 5.1 Aggregated economic development in constant prices. Dkk million.

Table 5.2. A baseline scenario for the development in waste generation in tonnes

The baseline scenario in Table 5.2 shows that the amounts of waste fractions 9 to 75 generally follow economic development of the sources, but that growth is slightly less than the growth in economic activity, especially in the case of waste from trade and services, which grows less than production of the aggregated branch. All in all, the baseline scenario shows an increase in waste over the period 1996 to 2005 as a result of growth in economic activity.

In the case of the three major fractions shown at the bottom of Table 5.2, the development is quite different. As mentioned earlier, residuals from coal-fired power plants decreases due to reduced coal consumption. Beet earth decreases due to an extraordinarily large amount in 1996 (a wet harvest season) and expected technological changes. Sewage from municipal treatment plants is expected to remain constant as the number of municipal waste water treatment plants is expected to remain unchanged. As a result, the total amount of waste from these three fractions decreases during the period.

Examination of the individual sources and fractions reveals some de-coupling. For instance, various non-combustible waste from households increases more than total private consumption, and the amount from trade and services increases less than production by the trade and service sector. This reflects the fact that different fractions of waste are linked to different economic activities and that in the present forecast/scenario, the different economic activities are assumed to increase differently. At the aggregated level, however, deviations from the overall economic growth tend to even out in the present forecast, and waste generation for the aggregated fractions follows general economic growth.

Model calculations of the change in the amount of waste when all or part of the economic activities are increased by 10% are shown in Tables 5.3 to 5.7. The figures in the tables are waste indices, where a value of 1.1 indicates a 10% increase in the amount of waste and a value of 1.05 indicates a 5% increase.

In Table 5.3, all economic activities have been increased by 10% except coal consumption by power plants, which has been kept constant. The table shows that under these circumstances, waste of the first four fractions increases by almost 10%, garden waste remains unchanged and waste for special treatment increases by only about 5%. Household waste and waste from the three production sectors increases between 8% and 10%. That the increase in total waste from each source is not 10% largely reflects the influence of garden waste and waste for special treatment. Waste from waste water treatment plants and other sources is almost independent of economic development and the amount of waste from these sources only changes marginally. In total, the amount of waste increases about 7%, or 850,000 tonnes.

Table 5.3. Change in the amount of waste generated by a 10% increase in all economic activities except coal consumption by power plants.

Tables 5.4 to 5.7 show the effects of changing the economic activity of the first four sources by 10% respectively, i.e. private consumption and production within the trade and service sectors, the manufacturing industries, and the building and construction industries, respectively. Comparing Tables 5.4 to 5.7 with Table 5.3 it is apparent, that sources are almost identical to the economic agents, i.e. a change in the private consumption mainly has direct effects on household waste while a change in the production within trade and service sector only has direct effects on waste generation by the trade and service sector.

The tables also indicate how much the individual sources contribute to changes in the amounts of waste. Of the 6.6% increase in total waste shown in Table 5.3, 1.5% is attributable to households (total in Table 5.4), 0.6% to trade and services, 1.8% to manufacturing etc. and 2.6% to building and construction. Similar information is also shown for the individual fractions.

Table 5.4. Change in the amount of waste generated by a 10% increase in private consumption.

Table 5.5. Change in the amount of waste generated by a 10% increase in production by the trade and service sector.

Table 5.6. Change in the amount of waste generated by a 10% increase in production by the manufacturing branches.

Table 5.7. Change in the amount of waste generated by a 10% increase in production by the building and construction sector.