Abstract:
This study evaluates the payback period, net present value (NPV) of benefits,
and internal rate of return (IRR) for four solar photovoltaic (PV) energy systems with
battery backup, designed for a vocational college building. The project duration 7
years, with a maximum investment of 70 million Baht and a discount rate of 396. -
Starting with the calculation of installable PV panels based on rooftop area, 41
panels were identified, requiring an investment of 254,200 Baht and generating 109.77
kWh per day, which is below the average daily consumption. Hence, the stand-alone
system is impractical and excluded from further consideration.
Among the remaining systems, the grid-connected system with a TOU (Time of
Use) meter is the most cost-effective. Next is the grid-connected system without TOU integration. The battery backup system with a TOU meter is not viable. Payback periods are 4.69, 5.25, and 7.78 years, with NPVs of 211,752.20, 86,788.91, and -157,091.72 Baht per project duration, and IRRs of 10%, 7%, and -3%, respectively.