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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]