SOLAR ENERGY SYSTEM CALCULATIONS

1.  SOLAR PANEL TYPE

  BC 670W Half-cut Monocrystalline PV Modules Aiko Solar brand (Tier 1 Solar PV Panel, China)  

 

2.  SOLAR SYSTEM CAPACITY

     Power per pc:  670W  

No. of panels:  12

     System capacity = 12 x 670 /1000 = 8.04 kWp

 

3.  TERMINOLOGY

     kWac (Inverter Capacity): The maximum continuous Alternating Current (AC) power  the inverter can output     

    kWp (Solar Panel Peak Capacity): The maximum Direct Current (DC) power the solar panels are rated to produce at peak sunlight   

     There is no direct math formula for conversion from kWac to kWp.     

     Standard practice: kWp = 1.1 to 1.4 times kWac.

     In my case, Solar Panel Size (kWp) = 1.6 x Inverter Capacity (kWac) = 1.608 x 6 = 8.04 kWp

4.  ESTIMATED MONTHLY ELECTRICITY GENERATION FROM SOLAR

     Assume Sun hours per day:  3.30 hrs.  (by Service Provider)

     Monthly electricity generated = 8.04 x 3.30 x 30 days = 796 kWh

     

    TNB's Maximum Allowable Quantity (MAQ):

    Solar installed capacity = 5.0 kWac

     Assume Sun hours per day:  5.00 hrs.

     MAQ = 5 kWac x 5 sun hours x 30 days (billing period) = 750 kWh 

5.  POTENTIAL SAVINGS ON ELECTRICITY COST PER MONTH

     Assumption:     30% solar generation for self-consumption during daytime and 70%  export to TNB Grid

     Rate for savings in daytime: RM 0.4443/kWh

     Rate from export (energy charge): RM 0.2703/kWh

     Solar usage consumed in daytime = 30% x 750 = 225 kWh

 Balance solar export to TNB = 70% x 750 = 525 kWh

Saving in daytime   = RM 0.4443 x 225  = RM 100

Saving from export = RM 0.2703 x 525  = RM 142

SST (daytime saving) = 8% x RM 100    = RM 8

 KWTBB (daytime) = 1.60% x RM 100    = RM 2

                                                                    -----------

Total saving per month                             RM 252

6.  RETURN OF INVESTMENT (ROI)                   

Solar system investment:    RM 19,000

Simple payback period = 19000 / 252 / 12 months = 6.28 years