The West Mesa School of Financial Gallantry is trying to determine whether they should replace their aging electric system with new, cost-effective solar panels with an expected life of 30 years. Annual energy expenditure under the old system is currently $70,000/yr, and expected to increase by 3% each year (including maintenance fees). Solar Panels would have no annual maintenance costs, but require an up-front expenditure of $1.2 Million.

If your discount rate is 4% for your school, should you invest in the solar panels?

I am trying to do this problem in excel but I do not know how to set it up or what formula to use.