Waste markets study: full report

Appendix 4: Capacity Modelling Assumptions

This appendix provides the following:

• Table 17: Waste Flow Assumptions
• Details of how "Other" Arisings has been calculated
• Table 18: C&I Waste Affected by the Ban
• Details of how facility capacity has been adjust to account for recycling performance (CV Adjustment)

Table 17: Waste Flow Assumptions

Note: *based on annual projected population growth rates from National Records of Scotland.

Table 18: Coding for C&I Arising Calculations

C&I Modelling Assumptions: Other Arisings and Affected by Ban

To calculate the percentage of material which is likely to be disposed of by alternative means to residual treatment ("Other"), the identified arisings for the material streams in Table 19 were compared to the total arisings in the commercial and industrial sectors.

Table 19 also details the material streams which have been assumed to be affected by the ban. It is assumed that in some cases these materials may be mixed in with the residual waste stream and therefore it is necessary to model the generation of all these wastes.

Table 19: Coding Assumptions for Business Waste

Waste Export to England for Treatment

Table 20 sets out the volumes of Scottish waste assumed to be treated in English facilities in 2016/17 and 2017/18. This is based on information on site return data obtained from the Environment Agency for waste facilities and landfills within approximately one hour's drive time from the Scottish border. The key facilities receiving waste in these years were:

• Suez West Sleekburn Materials Recycling Facility;
• Suez Byker Reclamation Plant; and
• Suez Ellington Road.

Table 20: Scottish Residual Waste Exports to England Assumptions

RDF Export Capacity

The capacity gap modelling includes figures for the current volume of residual waste exported from Scotland as RDF for treatment abroad. In the baseline it is assumed that this figure remains constant at the 2016/17 SEPA figure of 164,000 tonnes.

CV Adjustment for Scenario 1 (High Recycling)

As recycling performance improves under Scenario 1, it is anticipated that the CV of residual waste will reduce as the material composition changes. A recent residual waste composition for Scotland was not available, therefore to model the impact on CV change on the capacity of thermal treatment capacity, a baseline composition was developed based on current recycling rates for household and C&I waste. A future composition was then developed to reflect what the residual stream may look like as recycling targets are achieved (this is envisaged to contain less plastics, textiles etc.). It was assumed that the rate of change would be linear.

The baseline year for the modelling (2016/17) it is estimated residual waste would have a 9.82 CV, reducing to 8.30 CV by 2035/36. In 2016 it is assumed that the operational capacity (as detailed in the capacity modelling methodology) of the existing is utilised at 100%. As the CV reduces the capacity of the facilities increases, rising to 118% in 2035.

For this increase in capacity to occur in reality, treatment operators would need to increase the throughput of their facilities to maintain the level of power output which is currently achieved. It is assumed this change would be driven by the operators to prevent any losses to income from the facility.