Calculation of 1 million PV

Roofs Project Implemented in

Malaysia

Renewable Energy 2012

Norain Idris KGY110027

Umi Kalsom Ahmad KGY110028

Mohamad Firdaus Mohamed Annuar KGY110018

Examiner: Dr. Chong Wen Tong

This short assignment calculates energy generated and payback period of one million PV roofs

project implemented in Malaysia

ii

Table of Contents

Proposed Photovoltaic (PV) Roof System ............................................................................................. 1

System Components........................................................................................................................... 2

PV modules .................................................................................................................................... 2

Grid connected inverter.................................................................................................................. 2

Mounting ............................................................................................................................................ 3

Electrical design ................................................................................................................................. 3

Grid-connection ................................................................................................................................. 3

Monitoring ......................................................................................................................................... 3

Maintenance ....................................................................................................................................... 4

Expected Energy Generated ............................................................................................................... 4

Calculation of Expected Annual Energy Yield of The System ............................................................. 4

Calculating the Potential Monthly Savings from a PV System without Accumulating Electrical

Inflation Rate ......................................................................................................................................... 6

Calculating the Potential Annual Savings from a PV System Accumulating Electrical Inflation Rate 7

Payback Period Analysis........................................................................................................................ 8

References ............................................................................................................................................ 11

Appendices ........................................................................................................................................... 12

1

Proposed Photovoltaic (PV) Roof System

The proposed system is a 0.99 kWp photovoltaic system, which has some components price down-

scaled from a system used in a 9.9 kWp MBIPV project in Damansara Utama, Petaling Jaya

Selangor, Malaysia for commercial shoplots (Refer Figure 4). The components are mounting

structures, electrical works, labor and other miscellaneous expenses. The inverter price is quoted

from Sunny Boy and the PV modules price from Professional Factory. The prices for the 9.9kWp

MBIPV project can be referred in Figure 4. The prices below refer to prices of a photovoltaic (PV)

system (0.99 kWp) for a commercial PV roof in Malaysia.

Item Unit

price

(MYR)

Qty Total price

(MYR)

%

PV modules (165 W

each) (unit)

853 6 5,120 32.17

Inverter 1320 W (unit) 2,965 1 2,965 18.63

Mounting structures (lot) 3,202 1 3202 20.12

Electrical works (lot) 3,980 1 3980 25.01

Others, misc labour (lot) 650 1 650 4.08

System price 15,916.81 100.00

System power (kWp) 0.99

Price per kWp system 16,077.59

Figure 1: Proposed system price

2

System Components

PV modules

A total of 6 units of polycrystalline PV modules each having capacity of 165 Wp are used for every

PV roof, tilted at 7 degrees and mounted on flat roof as shown in. The system is installed for a

million PV roofs. Refer Figure 1.

The technical specifications area as follow:

Manufacturer: Professional Factory (165 Wp)

Power rating: 165 Wp

Type: Polycrystalline with frame

Dimension (LxWxD): 135x100x5 cm

Figure 2: PV module [4] SB1200 grid connect inverter

Grid connected inverter

The PV roof system consisted of one unit of grid connect inverter rated at 1200W as shown in Figure

2 with the technical specifications as stated below.

Manufacturer/model: Sunny Boy/ SB1200

Input (DC)

Max. DC power: 1320 W

Max. DC voltage: 400 V

PV-voltage range, MPPT: 100 V 320 V

Max. input current: 12.6 A

Number of MPP trackers: 1

Max. number of strings (parallel): 2

3

Output (AC)

Nominal AC ouput: 1200 W

Max. AC power: 1200 W

Max. output current: 6.1 A

Nominal AC voltage / range: 220 V 240 V / 180 V 260 V

AC grid frequency (self-adjusting) / range: 50 Hz / 60 Hz / 4.5 Hz

Phase shift (cos ): 1

AC connection: single-phase

Max. efficiency / Euro-Eta: 92.1 % / 90.9 %

Cooling: Convection

Dimension (W / H / D): 440 / 339 / 214 mm

Weight: 23 kg

Approval: MCS

Mounting The PV modules were inclined at 30 degrees and were mounted on aluminium support structure

above metal deck roof with hot dip galvanized steel mounting base.

Electrical design Each sub array is connected with 2 modules in series and 2 strings in parallel. The Building

Integrated Photovoltaic (BIPV) system is interconnected through in-direct feed method where the

output is fed back to the main distribution board (MDB) of the building to cater for internal load. The

electrical system installation was conducted by a certified electrician based on the Malaysian

Standard: MS 1837. The system installation and commissioning was supervised by the MBIPV

technical expert.

Grid-connection Output of the inverter was fed to the consumers main distribution board of the building (indirect

feed). An import-export meter was installed to monitor the energy generated and the meter was

located beside the main utilitys (TNB) supply meter at the customers incoming supply point.

Currently in Malaysia, interconnection to the grid is only limited to net-metering basis. The net-

metering for billing in this case is the difference between the electricity supplied to the customer

through the TNB meter measurement in the import mode, and the surplus PV generated electricity

exported to the TNB grid which is recorded by the TNB meter in the export mode. The PV meter

records the electricity generated by the PV system. The PV roof systems under this project are FiT-

ready.

Monitoring The PV roof systems will be monitored under standard monitoring starting Q3 2007 for a minimum

period of three years.

4

Maintenance The owner assumes ownership and responsibility of the system. System maintenance required is very

minimal. As Malaysia is located near to the equator with heavy rainfalls, the PV modules need no

regular cleaning. A regular check on cable tightness and connection on a scheduled interval is

encouraged.

Expected Energy Generated The expected electricity production is shown as follows:

_ Total number of PV modules installed : 6 units (165 Wp each)

_ Total PV capacity installed : 0.99 kWp

_ Expected annual energy yield : 1,097.3 kWh/year

_ Expected daily energy production : 3.0 kWh/day

Calculation of Expected Annual Energy Yield of The System

Array is rated at Pa.stc =0.99 kWp

Inverter efficiency: SUNNY BOY 1200 is 92.1%

Average daily maximum ambient temperature, Ta.day of 35 C

Allow 5% for manufacturers tolerance and mismatch

Dirt derating of 3%

Total voltage drop of 2%

Step 1: The derating of the PV array can be calculated by the following formula:

Parray = Pa.stc * fmm * ftemp * fdirt

Pa.stc =0. 99 kWp

fmm = 0.95 (5%)

fdirt = 0.97 (3%)

ftemp =1 - ( * (Tcell.eff - Tstc)) ( is taken as 0.43%)

= 1 - (0.43/100 x ((35 + 25) -25)); (Tcell-eff = Ta.day + 25C)

= 0.8495

5

Parray = Pa.stc * fmm * ftemp * fdirt

= 0.99 x 0.95 x 0.8495 x 0.97

= 0.775 kWp

Step 2: The average yearly energy output of the PV array is calculated as follows:

Epv = Parray x Htilt

Parray = 0.775 kWp

Htilt = 1,568 kWh/m2 (Irradiance at Petaling Jaya, tilted at 7 degrees)

Epv = Parray x Htilt

= 0.775 x 1,568

= 1,215.2 kWh per annum

Step 3: The sub-system efficiency can be calculated from the following formula:

pvss = pv-inv x inv

pvinv = 98% (2% voltage drop)

inv = 92.1%

pvss = pv-inv x inv

= 98% x 92.1%

= 90.3%

Step 4: The average yearly real energy yield of the PV system is calculated as follows:

Ereal = Epv x pvss

= 1,215.2 x 0.903

= 1,097.3 kWh per annum

= 3.0 kWh per day

Calculating the Potential Monthly Savings from a PV System without Accumulating Electrical Inflation Rate

Assumption: Average electric unit used by one home in Malaysia = 300 kWh

According to Tenaga Nasional Berhad (TNB) supplied electric rate, estimation of monthly electric bill for one home can be calculated as follows:

1) First 200 kWh (1-200 kWh) per month: (200 * 21.8)/100 (MYR) MYR 43.60

2) Next 100 kWh (201-300 kWh) per month: (100* 33.4)/100 (MYR) MYR 33.40

Estimated Bill = ((43.6 + 33.4)*100)/100 (MYR) MYR 77.00

The rate can be referred in Figure 5 in Appendices. Therefore;

Average monthly electric bill for 1 home (MYR) MYR 77.00

Average monthly electric bill for 1 million homes (MYR) MYR 77,000,000.00

Average kilowatt hours used per month for 1 home (kWh) 300

Average kilowatt hours used per month for 1 million homes (kWh) 300,000,000

Average no. of sunlight hour in Malaysia (h) 6.1

Monthly output of the proposed system = System power for 1 million homes x Hour no. of sunlight x 30 days (kWh/mo) 181,170,000

Calculated monthly output power of 1 million homes for real solar conditions = 49.53% reduction of rated monthly output power

(kWh/mo) 90,191,145.00

Saving percentage = Real output power for 1m homes/The actual average monthly use for 1m homes (%) 30.1%

Monthly bill saving for 1 million homes = Average electric bill multiplied by the saving percentage (MYR) MYR 23,149,060.60

7

Calculating the Potential Annual Savings from a PV System Accumulating Electrical Inflation Rate Assumption: Annual electrical rate inflation is 4% and average of used kWh unit per building is 300 kWh. This calculation is valid for one million buildings.

Year Malaysia annual electric bill for one

million homes

Electric Bill Savings

(%)

Electric Bill paid to

TNB Year 1 MYR 924,000,000 30.1% MYR 645,876,000

Year 2 MYR 960,960,000 30.1% MYR 671,711,040

Year 3 MYR 999,398,400 30.1% MYR 698,579,482

Year 4 MYR 1,039,374,336 30.1% MYR 726,522,661

Year 5 MYR 1,080,949,309 30.1% MYR 755,583,567

Year 6 MYR 1,124,187,282 30.1% MYR 785,806,910

Year 7 MYR 1,169,154,773 30.1% MYR 817,239,186

Year 8 MYR 1,215,920,964 30.1% MYR 849,928,754

Year 9 MYR 1,264,557,803 30.1% MYR 883,925,904

Year 10 MYR 1,315,140,115 30.1% MYR 919,282,940

Year 11 MYR 1,367,745,719 30.1% MYR 956,054,258

Year 12 MYR 1,422,455,548 30.1% MYR 994,296,428

Year 13 MYR 1,479,353,770 30.1% MYR 1,034,068,285

Year 14 MYR 1,538,527,921 30.1% MYR 1,075,431,017

Year 15 MYR 1,600,069,038 30.1% MYR 1,118,448,257

Year 16 MYR 1,664,071,799 30.1% MYR 1,163,186,188

Year 17 MYR 1,730,634,671 30.1% MYR 1,209,713,635

Year 18 MYR 1,799,860,058 30.1% MYR 1,258,102,180

Year 19 MYR 1,871,854,460 30.1% MYR 1,308,426,268

Year 20 MYR 1,946,728,639 30.1% MYR 1,360,763,318

Year 21 MYR 2,024,597,784 30.1% MYR 1,415,193,851

Total average MYR 1,406,644,876

MYR 983,244,768

Potential average annual savings of electric bill for one

million homes

MYR 423,400,108

Payback Period Analysis Assumptions: Loan repayment perios is 10 years at interest rate of 2%. Feed-in tariff is MYR 1.50 (Installed capacity up to and including 4 kWp = MYR 1.23

and additional for installation in buildings or building structures = MYR 0.26), which paid by government for 21 years.

System price for one home (Refer Figure 1) MYR 15,916.81

Let assume that all homes take loan at interest rate 2% for 10 years and install the system in the same year (2011)

Interest rate 2.0%

No of loan repayment years 10

Total loan per month for one home MYR 159

Total loan per month for one million homes MYR 159,168,100

Total loan per year for one million homes MYR 1,910,017,200

ANNUAL PRODUCTION FOR ONE MILLION HOMES

Number of Panels 6,000,000

STC Rating in Watts Per Panel 0.165

Total kW assuming optimum conditions 990,000

Average hours of sunlight per day [1] 6.1

Total kWh per day assuming optimum conditions 6,039,000

Total kWh per year assuming optimum conditions 2,204,235,000

Performance under real world solar conditions 49.78%

Estimated total kWh per year in real conditions 1,097,325,598

Estimated kWh per day output in real conditions 3,006,372

Feed in tariff (1.23/kWh) for a million homes MYR 1.50

Malaysia annual electric bill for one million homes for year 1, i.e. 2011 MYR 924,000,000

Electrical Rate Annual Inflation Assumption 4.0%

Electric Bill Savings (%) 30.1%

Annual Electric Bill Savings for the first year (MYR) MYR 278,124,000

Total System Cost for one million homes MYR 19,100,172,000

Annual feed in tariff paid by government for million homes MYR 1,645,988,396

Total feed in tariff for 21 years paid by government for million homes MYR 34,565,756,324

End of payback year (Year x) 12

9

From excel spreadsheet calculation, cash flow for the system for 21 years can be seen as follows:

Year 2011 2012 2013 2014 2015 2016

-19,100,172,000

Total Income (MYR) 1,645,988,396 3,291,976,793 4,937,965,189 6,583,953,586 8,229,941,982 9,875,930,378

Annual feed in tariff paid by government for million

homes (MYR)

1,645,988,396 1,645,988,396 1,645,988,396 1,645,988,396 1,645,988,396 1,645,988,396

Total Outlay (MYR) 1,910,017,200 3,820,034,400 5,730,051,600 7,640,068,800 9,550,086,000 11,460,103,200

Annual loan repayment for system cost of one million

homes (MYR)

1,910,017,200 1,910,017,200 1,910,017,200 1,910,017,200 1,910,017,200 1,910,017,200

Net gain (MYR) -264,028,804 -528,057,607 -792,086,411 -1,056,115,214 -1,320,144,018 -1,584,172,822

2017 2018 2019 2020 2021 2022 2023 2024 2025

11,521,918,775 13,167,907,171 14,813,895,567 16,459,883,964 18,105,872,360 19,751,860,757 21,397,849,153 23,043,837,549 24,689,825,946

1,645,988,396 1,645,988,396 1,645,988,396 1,645,988,396 1,645,988,396 1,645,988,396 1,645,988,396 1,645,988,396 1,645,988,396

13,370,120,400 15,280,137,600 17,190,154,800 19,100,172,000 19,100,172,000 19,100,172,000 19,100,172,000 19,100,172,000 19,100,172,000

1,910,017,200 1,910,017,200 1,910,017,200 1,910,017,200 - - - - -

-1,848,201,625 -2,112,230,429 -2,376,259,233 -2,640,288,036 -994,299,640 651,688,757 2,297,677,153 3,943,665,549 5,589,653,946

2026 2027 2028 2029 2030 2031

26,335,814,342 27,981,802,739 29,627,791,135 31,273,779,531 32,919,767,928 34,565,756,324

1,645,988,396 1,645,988,396 1,645,988,396 1,645,988,396 1,645,988,396 1,645,988,396

19,100,172,000 19,100,172,000 19,100,172,000 19,100,172,000 19,100,172,000 19,100,172,000

- - - - - -

7,235,642,342 8,881,630,739 10,527,619,135 12,173,607,531 13,819,595,928 15,465,584,324

From the analysis, the payback period for the proposed system is 12 years. If the system is built in year 2011, the end of payback is year 2022. From above

calculation, income which amounts about 15,500,000 is gained after 21 years. The calculation can be referred in Excel spreadsheet enclosed in CD.

Figure 3:Payback period of the proposed PV roof system

From Figure 3, it can be clearly seen that income from the feed-in tariff (FiT) overcomes expenses of

the project which is in this case annual loan repayment.

It also can be extracted that the payback year is Year 2022 and it takes 12 years until the system cost

is covered.

0

5

10

15

20

25

30

35

40

2010 2015 2020 2025 2030 2035

Am

ou

nt

Bill

ion

s

Year

Total Income and Total Outlay vs Year

Total Income (MYR)

Total Outlay (MYR)

11

References

[1] http://www.malaysia.climatemps.com/

[2] http://www.tnb.com.my/residential/pricing-and-tariff/tariff-rates.html

[3] http://www.tnb.com.my/residential/pricing-and-tariff.html

[4] http://gold.dhgate.com/product/-order-match-back-high-level-165w-solar-

panel/p136566544.html

[5] KeTTHa, Handbook on the Malaysia feed-in tariff for the promotion of renewable energy,

2011

12

Appendices

Item Unit price

(RM)

Qty Total price

(RM)

%

PV modules

(165 W each)

3,050 60 units 183,000 63

Inverter

(3.6 kW each)

9,560 3 units 28,680

10

Mounting structures 32,020 1 lot 32,020/3 11

Electrical works 39,800 1 lot 39,800/3 13.8

Others, misc labour 6,500 1 lot 6,500/3 2.2

System price (9.9 kWp) 290,000 100

Price per kWp system 29,293

Figure 4: System installed in MBIPV project in Damansara Utama, Petaling Jaya Selangor,

Malaysia

TARIFF CATEGORY UNIT RATES

1. Tariff A - Domestic Tariff

For the first 200 kWh (1 - 200 kWh) per

month

sen/kWh 21.8

For the next 100 kWh (201 - 300 kWh)

per month

sen/kWh 33.4

For the next 100 kWh (301 - 400 kWh)

per month

sen/kWh 40.0

For the first 100kWh (401 - 500 kWh)

per month

sen/kWh 40.2

For the next 100 kWh (501 - 600 kWh)

per month

sen/kWh 41.6

For the next 100 kWh (601 - 700 kWh)

per month

sen/kWh 42.6

For the next 100 kWh (701 - 800 kWh)

per month

sen/kWh 43.7

For the next 100 kWh (801 - 900 kWh)

per month

sen/kWh 45.3

For the next kWh (901 kWh onwards)

per month

sen/kWh 45.4

The minimum monthly charge is RM3.00

Figure 5: TNB Electric Supplied Tariff [2]

* The tariff is inclusive the subsidised rate by government=21.8 sen/kWh [3]

13

Capacity of renewable energy installation FiT rate

(RM per

kWh)

Effective period Annual

degression

rate

Installed capacity up to and including 4 kWp 1.23 21 years 8%

Installed capacity above 4 kWp, and up to and

including 24 kWp 1.20 21 years 8%

Installed capacity above 24 kWp, and up to

and including 72 kWp 1.18 21 years 8%

Installed capacity above 72 kWp, and up to

and including 1 MWp 1.14 21 years 8%

Installed capacity above 1 MWp, and up to

and including 10 MWp 0.95 21 years 8%

Installed capacity above 10 MWp, and up to

and

including 30 MWp

0.85 21 years 8%

Additional for installation in buildings or

building structures +0.26 21 years 8%

Additional for use as building materials +0.25 21 years 8%

Additional for use of locally manufactured or

assembled solar photovoltaic modules +0.03 21 years 8%

Additional for use of locally manufactured or

assembled solar inverters +0.01 21 years 8%

Figure 6: Fit-in Tariff [5]