# Questions & Answers

If I install a 4kW PV System on my roof top with SEDA 15th March 2014 Feed-in-Tariff rate:

Q1. How much money I will receive from TNB per month?

## 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 = kW_{PV}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.

**Notes:**

- the PSH (Peak Sun Hour) in KL is a conservative value of 1200h per year, or 100hr per month or 3.3hr per day.
- 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.
- 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.
- 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.
- 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.