How Long Does It Take To Recover The Cost Of Photovoltaic Power Generation On a 500㎡ Roof?

(1) The power of a single PV module can reach more than 500 watts, and the area is about 2.5㎡ (2.2m*1.13m), which is equivalent to 200 watts per square meter. According to the flat installation, theoretically, a 500㎡ roof can be installed with a 100-kW PV panel;

(2) Considering the installation angle, some area can be saved, and the saved area can be used as a maintenance channel, so in fact a 500㎡ roof can be installed with a 100-kW PV panel.

For example: the annual average effective sunshine hours for photovoltaic power generation in a certain place is about 1029 hours. Since a 100-kilowatt photovoltaic panel can generate 100kwh of electricity per hour, the annual power generation is about 100kwh/hour*1029 hours=102900 degrees=103,000 kWh. Considering that the photovoltaic grid-connected inverter has about 3% loss, the overall power generation is about 100,000 kWh.

Based on the construction cost of about $430 per kilowatt of photovoltaic power generation, the cost of 100 kW of photovoltaic power generation is about $430/kW*100 kW=$43,000.

(1) Consider the average electricity cost on a monthly basis: According to the electricity price on a company's electricity bill, the monthly electricity cost is about $0.14 per kWh;

(2) Consider the average electricity cost based on peak and off-peak hours: 8:00-11:30 is the peak hour (electricity cost is about $0.15/kWh), and 11:30-18:30 is the off-peak hour (electricity cost is about $0.1/kWh).

Calculation rules:

Since photovoltaic power generation is carried out during the day, the electricity cost saved by power generation can be simply equal to the average value of peak and flat periods. The electricity cost saved by photovoltaic power generation during the day is (1+0.83)/2=0.92RMB(0.13USD)/kwh.

Payback period:

The annual power generation income is 100,000 kwh*0.92=92,000 RMB(13,000USD), and the investment payback period is 30/9.2=3.26 years.