Energy and Environmmental Problem Solving (Energy and Environmental Dynamics) TEP4220 Week 34 Exercises Fri 20.08 Klaus Vogstad Dept. of Energy and Process Engineering klausv@stud.ntnu.no 1/11

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The four rules of Causal loop diagramming Rule (i) An increase in x results in an increase of y Rule (ii) An increase in x results in a decrease of y Rule (iii) An even number of negative polarities along a loop is a reinforcing loop R Rule (iv) an odd number of negative polarities along a loop is a balancing loop B Reinforcing growth (exponential growth or exponential decline) Goal seeking behaviour (exponential decay or limiting growth) 1/11

Figure 3-4 US oil production, consumption, imports, and price over a 130-year time horizon Source: Production & consumption: 1870-1949, Davidsen (1988); 1950-1966, EIA Annual Energy Review. 1880-1968, Davidsen (1988); 1968-1996, EIA Annual Energy Review, Refiners Acquisition Cost.

Modeling is an iterative process