While many sustainability projects make sense from an environmental or ethical standpoint, people will be reluctant to invest capital unless the project makes business sense. Does the project have a reasonable return on investment? Pick an existing sustainability or LEED project, either from internet research or from a local project that you are familiar with, and discuss this project from the stand point of economics. Look at such things as initial investment costs and life-cycle costs, cost-benefit analysis and pay-back period. We want to show that sustainability is not only good for the environment, but also for the bottom line.