**Energy Resources in the FTT family of models**

Technology diffusion in the FTT family of models of substitution in order to remain within feasible limits of the natural system. This is done by using a global database of energy resources. Its conceptual framework is given here using the image above. This was constructed by the ESM group at 4CMR [1] based on an extensive literature review and some original calculations.

*economic potential*. The total amount of resources can be obtained if one is willing to pay a very high cost, and this corresponds to the

*technical potential*.

*cost-supply curve*(c). This expresses the cost of an additional amount of resource given that a certain quantity has already been consumed. The cost becomes very high for high consumption rates.

*really*know the total amounts of resources available, only estimates can be obtained. Existing estimates vary significantly in the literature. Therefore, it is more appropriate to express cost-supply curves in terms of ranges, or probability distributions of how much resources are thought to be available to the best of current knowledge (d). We present this as a range delimited by three curves, two red curves for the upper and lower limits, and a blue curve for the statistical

*mode,*such that there is a 96% chance that the

*real*cost-supply curve (if it was possible to know it) lies within that range.

[1] J.-F. Mercure and P. Salas, An assessment of global energy resource economic potentials, *Energy*, 46, 322-336 (2012), Free text available on *ArXiV* arXiv:1205.4693v2