There are two aspects of a Transformation which govern the size of its Output, and hence the subsequent requirement for secondary equipment, or the size of an element determined by that Transformation. Firstly, all Transformations have at least one Input, which identifies an element as a source of demand; together with a Basis, which specifies the particular result, associated with that element, which defines the size of that Input in any year. For the simplest Resource and Service Transformations, the size of the Input defines the size of the Transformation Output directly – see 10.3.34.13 Resource Transformation.
Using a Transformation to install a Secondary Resource
More generally, the Output is calculated as some function of the Input, or Inputs. The Multiplier, Input–Output Mapping, Erlang B Formula and Time Lag Transformations implement pre-defined functions, which are governed by specific parameters for those particular types of Transformation; while the Expression Transformation allows you to enter a function of your own, defining the Output as a function of up to eight Inputs.
Note: Most of these relationships can be defined directly by dragging between the respective icons – see 4.4.8 Connecting elements.