Basic idea is to model demand with endogenous growth (but "satiation" becomes possible - eventually - at some notional "sufficiency" level); and supply then tracks demand with some time lag (~5-50 years(?), characteristic of commissioning/decommissioning large scale energy infrastructure). Then add cumulative pollution, with a hard constraint/limit which trumps demand and forces supply (of any non-zero polluting source) to zero. In this version we have one source (so no substitution is possible), and it produces a cumulative pollutant, so we expect to see supply decline and/or crash (according to the specific parameters and dynamics). Of course, "demand" will still carry merrily on its way up anyway, but the interpretation of the consequently growing supply shortfall will be left to the eye of the beholder. In this version we try to "smooth" the decline - using the fractional "exhaustion" of the pollution "quota" as feedback signal to smoothly shift from a dynamic of "supply chasing demand" and one of "exponential mitigation of supply within the remaining pollution quota". This particular dynamic is rigid about not exceeding the quota: it does not allow (and could not cope with) overshoot. There is also no provision for delay in the feedback (that could perhaps be added, and would presumably allow a more prolonged addiction, but then more rapid and painful withdrawal?).