Scottish Aggregates Levy: evidence review and policy options

Appendix 1: Introduction

These technical appendices set out the data and methodology used in the Scottish Aggregates Levy model developed for this work, as well as the detailed Northern Ireland case study.

Two types of aggregates were modelled, these are: primary aggregates (crushed rock and sand and gravel), and secondary aggregates i.e. recovered material from construction and demolition (C&D) waste which is sold as a secondary material for use in construction projects.

The modelling approach for Phase 1 of this work was comprised of two key stages, as detailed in Appendix 2, these are:

• Historic baseline - all available aggregates data was reviewed and used to compile a historic dataset of aggregates flows in Scotland; and
• Forward projections - based on likely growth rates, projections of aggregates flows out to 2030 were created for a 'no change' (or Business as Usual) scenario i.e. where the current rate of Aggregates Levy is assumed to stay constant in future years.

Phase 2 of this work involved further development of the Scottish Aggregates Levy Model to model some illustrative impacts of varying the Levy rate. Though data is restrictive, demand elasticities were developed and applied to estimate the impacts on production, import and export of primary aggregates, recycling of secondary aggregates, and the economic impacts in terms of levy revenue. Environmental externalities are also calculated. This is described further in Appendix 3.

These modelling stages are described further for each type of aggregates in Appendix 2 and Appendix 3, respectively, while the Northern Ireland case study is presented in Appendix 5.