Spreadsheet Solution
A spreadsheet analysis for this example is shown in Figure 10-4. For each
mutually exclusive project, the PW of total benefits (cells B11:B13) and the PW
of total costs (cells C11:C13) are calculated. Note that annual operating and
maintenance costs are included in the total cost calculation in accordance with
the conventional B–C ratio formulation.
Since the projects are mutually exclusive, they must be ranked from smallest
to largest according to the equivalent worth of costs (do nothing → A → B → C). The B–C ratio for Project A is calculated to be 1.34 (row 17), and Project A
replaces do-nothing as the baseline alternative.
Project B is now compared with Project A (row 18). The ratio of incremental
benefits to incremental costs is less than 1.0, so Project A remains the baseline
alternative. Finally, in row 19, the incremental benefits and incremental costs
associated with selecting Project C instead of Project A are used to calculate an
incremental B–C ratio of 1.16. Since this ratio is greater than one, the increment
required for Project C is acceptable, and thus Project C becomes the recommended
project.