Questions & Answers

How much money I will receive from TNB per month?

Expected Electrical Energy generated (E) in kWh (or Unit of Energy) is given by the equation below:

E = kWPV x PSH KL p.a. x ( Factors of Dirt, Temperature, Manufacture Mismatch of PV module) x (Efficiencies of Electrical System & Inverter)

Thus, for 4kW system...

E = 4kW x 1200 hr p.a. x (1.0 x 0.85 x 0.97) x (0.95 x 0.97); (Note: New system, dirt factor = 1.0)
  = 3647 kWh per annum.
  = 303 kWh per month.
FiT rate = Basic rate + Bonus rate
  = 1.0184 + 0.2153 (on roof top) + 0.05 (if use Malaysian made PV module).
  = MYR 1.2837 / kWh.

Therefore, monthly you will expect to collect money for selling RE power to TNB, and it amounts to 303 kWh per month x MYR 1.2837 / kWh = MYR 388 monthly.

How long before I recover my cost?

Your Payback Period = MYR 38,888.00 / ( MYR 388 x 12 mth.) = 8.35 years.

Thus, 21 years - 8.35 year, you will have another 12.65 years to collect the Free income.


  1. the PSH (Peak Sun Hour) in KL is a conservative value of 1200h per year, or 100hr per month or 3.3hr per day.
  2. Other Factors due to Nature (dirt, temperature & PV module) plus due to System choice (cable losses & Inverter efficiency) are typical system design values we use for calculations.
  3. Payback period of 8.35 years, may be shorten if the PV System is well maintain and do not have shadows over the years, say due to neighbour's tree.
  4. Another 12.65 years of power output will reduce over time due to dirt as compared to new ones (dirt factor = 1.0) We typically use a dirt factor of 0.97 for existing systems. Thus, monthly income may fluctuate to slightly below MYR 388 monthly.
  5. Generally, you would be able to receive slightly lower that a total of 2.5 times of your initial investment for the whole of 21 years period.(MYR 38,888 x 2.5 = MYR 97,220)

What are other costs for the duration of 21 years REPPA (Renewable Energy Power Purchase Agreement) with TNB?

Maintenance cost is minimal.

  • PV modules with regular cleaning of half yearly or yearly is sufficient. Use only non-pressured water.
  • Inverter with default 5 years warranty keep you mind free for 5 years.
  • Additional Extended Warranty can be purchased from Inverter manufacturer upon request.
  • DC & AC components hardly spoil unless hit by lightning or due to system fault, which need further investigation.
  • If interested, you can do your own monitoring of energy output as all Inverter manufacturers include owner access to log in to installed Inverter.
  • Else, we can monitor for you with a Performance Monitoring Contract or Yearly Maintenance Contract.

Please do contact us for further information of your solar PV system maintenance.