Transport scenarios and modelling techniques for environmental impacts prediction in the aggregates market
Résumé
The growing demand in construction aggregates is confronted with increasing environmental constraints. Since the average transport distances from the quarries to the consumption centres are permanently increasing, they are mainly responsible for the CO2 emissions within the construction minerals market. A macroeconomic System Dynamics model representing the French aggregates supply and transport market predicting environmental impacts on a national scale has been built in the French-Austrian research project ANTAG (Anticipation of the access to the aggregate resource by breaking present schemes in the long term). Modelling each mode of transportation allows comparative impact analyses of CO2, transport flows, land-use and energy consumption on the basis of scenario simulations. The results of two transport scenarios are compared to the base case introducing new modelling techniques. One scenario studies the effects of a move away from road transport towards alternative transport modes. The second scenario focuses on foreign aggregates penetrating the French market on a large scale and notably their transport. For both cases the implementation of transport capacity saturations of the alternative modes was required. Other secondary mechanisms such as the effects on the market equilibrium in the imports scenario are considered within the supply-and-demand module. Uncertainty analysis was performed for the submodel extension required for the scenarios.