Q2: The designer of the penstock for a small hydroelectric cogeneration station has the option of using steel pipe, which costs $150,000 installed and requires $4000 yearly for painting and leak-checking maintenance, or DSR4.3 (heavy-duty plastic) pipe, which costs $170,000 installed and requires $1150 yearly for leak-checking maintenance. Both options have an expected life of 30 years. If the interest rate is 8%, which choice has the lower present equivalent cost, and how much lower is it?