When calculating FCF, where does opportunity cost go?

Example: The introduction of the new line of vehicle parts will cause a net decrease of $50,000 in profit contribution after taxes, due to a decrease in sales of the other lines of tester machines produced by the company. Life of project is 5 years.

Does the opportunity cost go in Year 0 or is that 50,000 going to be for years 1-5 ( year 1: 50,00, year 2: 50,000 etc)