If the new project will reduce cash flows from the firm's other projects, then this is a negative externality anbe considered in the analysis. Consequently, these should be considered costs of the new project and wouldthe project's NPV. If the project can be housed in an empty building that the firm owns and could sell if it wused for the project, then this is an opportunity cost which should also be considered as a "cost" of this projThe after-tax sales amount for this building will reduce the project's NPV