*3.2. Cost Models*

This Section details the various cost components by category, and it maps them to the cost layer template. Notice that the presence of multiple cost models makes the cost signal connecting components to the bus rather an array of cost values, as sketched to Figure 2a, where each array element denotes one cost category listed hereafter. In the following, we will use uppercase letters *C* to denote cumulative costs; i.e., costs whose definitions encompasses the time intervals over which they are accrued. Lowercase *c* denotes instantaneous costs. The former are expressed in currency × time, e.g., \$ × year, and the latter in currency.
