A secondary school is planning a major upgrade by setting up a solar panel system. The goal is to choose the system that offers the best financial value over its entire lifespan. The school is evaluating two solar panel providers, SolarSmart and EcoSun.
School’s current electricity usage:
The school uses an average of \(17\,000\) kilowatt hours (kWh) of electricity per year.
The cost of electricity is $0.30 per kWh.
Information on the solar panel providers:
| Company | Number of Panels | Type of Panel | Total Installation Cost | Annual Maintenance Cost |
|---|
| SolarSmart | \(50\) | Fixed tilt at \(25^\circ\) | \(\$66\,000\) | \(\$340\) |
| EcoSun | \(45\) | Adjustable tilt | \(\$64\,000\) | \(\$360\) |
Each panel’s wattage is \(320\) Watts (W) at \(100\%\) efficiency.
The average sun angle at the school’s location is \(30^\circ\).
For every \(1^\circ\) difference between the panel tilt and the sun angle, the panel’s efficiency drops by \(1\%\).
Both solar panel systems are guaranteed to last for 25 years.
Additional information:
Singapore gets an average of 4.2 hours of peak sunlight per day.
Solar panel output in daily watt hours = solar panel wattage \(\times\) peak sunlight hours \(\times75\%\).
The school can sell any extra energy it does not use back to the grid for $0.20 per kWh.
Calculate, in watt hours, the daily power output per panel for SolarSmart.[2]
Find the total daily power output from each company, leaving your answer in kilowatt hours (kWh).[2]
Recommend which company the school should choose. Justify your decision and show your calculations clearly.[5]
State one assumption made in your calculation in (c).[1]