Question

Suppose your monthly electrical usage is 950 kWh. You want to use a solar panel system to generate your own power and the solar panels that can produce 240 W costs $250 per panel. There will be an add-on cost of 25% on the cost of the panels for accessories and installation. Assuming that a month is of 30 days and each day you have an average of 5 hours of sunlight, determine the number of months that it will take for the solar panel investment to pay off. Energy cost $0.15 per kWh.

Answer 1

Monthly Electrical usage = 950 kWh

Daily Usage = 950/30 = 95/3 = 31.67 kWh

Per hour requirement = 95/(24*3) = 1.32 kW

Solar panels need to be produced 1.32 kW daily in 5 hours,

Single solar panel produce = 240 W per hour

Solar Panel Cost = 250 $

Average sunlight available per day = 5 hours

Energy Cost = 0.15 per kWh

No. Of solar panels will required = 1320/(240*5) = 1.1

cost for solar Panels = 250*1.1 = 275 $

Add-on cost = 275*0.25 = 68.75

Total cost for solar Panels = 275 + 68.75 = 343.75 $

Time taken for the solar panel investment pay off = 343.75/(0.15*24)

       = 95.5 days

       = 3 months, 5 and half days