3-4-2 Discount of benefit to present value
The estimated benefits in each year in the project life is discounted to the present value with the formula:
present value of benefit item n : BofPV
d: span of construction period(years)
T: span of Project Life: 40 years
t: year from the Base
B: benefit for item n(yen) in t th year
r: social discount rate :4%
n: benefit item
The present value of total benefit for the project is calculated as the sum of the over all benefit items