When the plant is being built, the first couple years,...

When the plant is being built, the first couple years, appreciation and Amortisation is very minimal.
Tax wise, the company will pay less tax due to the offset of all the expenses or oftenly they will defer the tax to later years.
Anyhow we should not be worry about the NPV, thats how finance institutions fund major projects.
return of less than 3-4 years is very ideal.
other two guys just want to stir things up for panic sell from retail holders.