Deep Pocket Fund (DPF) has a solar energy project under evaluation. The initial investment of this project includes land purchase and a solar energy generating system. Deep Pocket Fund has no plan to operate it forever. Their strategy is to set up the energy plant and sell the energy to the spot market as a long-term project. As a financial analyst of DPF, your manager asked you to evaluate the project, and offer advice on which solar system they should adopt. The detailed information is as below: 1. Project life is 30 years. 2. Land cost $5 million. The land is expected to appreciate by 1.5% per year over 30 years. Assume your cost of land is a fair market value and you are expected to sell the land at fair market value by the end of 30 years. 3. You have a choice of choosing fixed solar panels or rotating solar panel systems. 1 MWh (1000 kW per hour) system of rotating panel systems costs $1.3 million. Your purchased land allows you to build a 25MWh system. A rotating solar system is more efficient in producing solar energy with an average output of 5.6 hours per day. The maintenance cost is about 10% of the sales revenue. 4. If you use fixed solar panel systems. 1MWh (1000 kW per hour) system costs $1.1 million. You can build a 30MWh system as the fixed systems require less space. However, the effective output from the average daily sunshine is about 4.5 hours. The maintenance cost is about 8% of the sales revenue. 5. You can sell your electricity to the spot market at price of $80 per MWh in the first three years and then the price will increase by $2 every three years. You will also get a government bonus of $70 per MWh (e.g, Large-Scale Generation Certificate) for the first 5 years. 6. After 30 years, it will cost you $50,000 to dump all equipment and clean the site. 7. Additional assumptions: - The discount rate for the project is 8%. - The tax rate is constant at 30%. Capital gains tax is 15% for land sales after 30 years (50% discount of the normal tax rate). - Straight line depreciation of solar systems with zero salvage. - 365 days per year. - Both systems will lose 0.75% efficiency per year.

Task: What NPV of rotating solar system when discount rate is 4%, 8%, 12% and 16% respectively. From the result, concluse which level of sensitivity of rotating system?