Question

A remotely located air sampling station can be powered by solar cells or by running an above ground electric line to the site and using conventional power. Solar cells will cost $18,000 to install and will have a useful life of 5 years with no salvage value. Annual costs for inspection, cleaning, and other maintenance issues are expected to be $2,400. A new power line will cost $27,500 to install, with power costs expected to be $1,000 per year. Since the air sampling project will end in 5 years, the salvage value of the line is considered to be zero. At an interest rate of 10% per year,

a. Which alternative should be selected on the basis of an annual worth analysis
b. What must be the first cost of the above ground line to make the two alternatives equally attractive economically?

Answer 1

Answer:

a) should install the solar cells

alternative 1, solar cells

initial investment $18,000

annual expenses $2,400 (5 years)

NPV =  $27,097.89

AW = (10% x $27,097.89) / [1 - (1 + 10%)⁻⁵] = $7,148.36

alternative 2, power line

initial investment $27,500

annual expenses $1,000 (5 years)

NPV =  $31,290.79

AW = (10% x $31,290.79) / [1 - (1 + 10%)⁻⁵] = $8,254.43

b) $23,307.10