Balance of Systems- Solar PV Project

Gensol Engineering Pvt Ltd

Balance of Systems (BOS)

• Inverters

• Mounting & Racking Systems

• Electrical Equipment and Installation

• Cabling-AC & DC

• Transformers & Breakers

• Combiner Boxes

• Earthing

• Transmission Line, etc

• Civil Work & Development

• Inverter Rooms, CMCS

• Roads, Boundary, Drainage, Cleaning Systems, etc

• Land

• Miscellaneous

All components of a photovoltaic system other the photovoltaic

panels“ ”

BOS Trends

-10.00

10.00

30.00

50.00

70.00

90.00

110.00

2010-11 2011-12 2012-13 2013-14 2014-15 2015-16 2016-17

NormalizedValue

N o rmal izedCERCPVCo stCu rves

ProjectCost ModuleCost BOSCost

0.00%

20.00%

40.00%

60.00%

80.00%

100.00%

2010-11 2011-12 2012-13 2013-14 2014-15 2015-16 2016-17

Module-BOSCostBreakup

Module BOS

• Module cost curve has

outrun BOS cost curve

• BOS optimization from

2013-14

• Module:BOS at 65:35

• Module CARR~ 9%

• BOS CARR ~8%

Cost Breakup

Head Components Trend

Inverters

MountingStructures MMS,Fasteners, Installation

Civil Works&Development Rooms,Roads,Boundary,Drainage,Cleaning, etc

ElectricalBOS Cabling, Transformers, Breakers,Combiner Boxes,Earthing,etc

Land

Miscellaneous CCTV,Monitoring, etc

Module65%

Inverters4%

MountingStructures

7%

CivilWorks&Development

7%

ElectricalBOS10% Land

6%

Miscellaneous1%

SolarProjectCostBreakup

BOS Reduction due to Module Efficiency

• Efficiency of average commercial wafer based silicon module has grown from 10% to 17% in last 10 years

• Best efficiency multi-crystalline module: 19.2%

Source: Fraunhofer ISE, 2016

BOS Reduction due to Module Efficiency

Impact of increase in module efficiency

Item Components SavingTrendScalable DCCabling,Structures, SCBs,

Connectors, Land

Semi-Scalable Roads,Periphery,Drains,LightingNeutral ACBOS,Evacuation, etc

0.0%

2.0%

4.0%

6.0%

8.0%

10.0%

12.0%

14.0%

16.0%

18.0%

Efficiency DCWorks Structure Ass.CivilWork Land

0.0% 0.0% 0.0% 0.0% 0.0%

8.3% 8.0% 7.7%6.0%

7.7%

16.7%

14.1%

16.7%

11.1%

14.2%

%CostSavings

CostSavings- EfficiencyIncrease

300W 325W 350W

For every 5W increase in module wattage

• project costs decrease by 0.27%

• BOS costs reduce by 0.8%

BOS Reduction due to Overloading (DC:AC)

Impact of increase in overloading (DC:AC)

Item Components SavingTrend

Neutral DCCabling,Structures, SCBs,Connectors,Land

Semi-Scalable Roads,Periphery,Drains,Lighting

Scalable ACBOS,Evacuation, etc

BOS Reduction due to Overloading (DC:AC)

1.00

0.960.94

0.920.91

0.90

1.0000.984 0.979 0.972 0.968 0.962

0.840.860.880.900.920.940.960.981.001.02

0 10% 15% 20% 25% 30%

NormalizationFactor

Overloading(%)

EffectofOverloadingonPlantCosts

NormalizedBOSCost/Wp NormalizedCost/Wp

1.000

1.0831.125

1.1671.209

1.251

1.00

1.10

1.15

1.20

1.25

1.30

1.000

1.050

1.100

1.150

1.200

1.250

1.300

0 10% 15% 20% 25% 30%

NORM

ALIZED

GAIN

OVERLOADING(5)

CostBenefit AnalysisOf Overloading

Normalized NormaizedEnegyGain

For every 10% increase in overloading

• project costs decrease by 1.25%

• BOS costs reduce by 3.5%

Cost Benefit Analysis

• Till Generation gain surpasses increase in cost

DC Cabling & Combiner Boxes

DC side cabling costs have decreased by about 40% due to efficient

design in the last few years

Smart DC Block Sizing

55:45 65:35 75:25

55:35 65:35 75:25

Cost(%) 100% 115% 124%

Loss(%) 100% 113% 120%

OverallCost(INR/Wp) 0.23 0.37

• Big Plant sizes allow DC block sizing optimization

DC Cabling & Combiner Boxes

String Fusing by Y-connectors-> Solar Cable & SCB Cost reduction by around 30%

String Monitoring removed, relying on inverter zone monitoring

Item Saving

SolarCable 32%

SCB 26%

Overall 28%

Leap Frogging saves 25% cable cost in the case of tracker

With effective design optimization on the DC side, a reduction

of 1.1% and 3.6% on project cost and BOS can be achieved“ ”

Inverters & Transformers

Inverters• Inverter costs have reduced by more than 70% from 2010-11

• Driven by

o Scale of Production (Inverter learning rates vary from 18-20%)1

o Technological advancements:

ü Material (SiC, GaN)

ü Block Size

ü Voltage Increase (1500V)

o Localization

• Inverters are predicted to see price reductions of 8-9% per annum upto 20202

Tranformers• Have shown reduction in costs in recent years due to:

• Higher transformer capacities due to bigger block size

• Metal Prices

• Multi- winding transformer (5-winding, 7 winding) resulting in BOS optimizationSource: 1. Fraunhofer ISE, 2015

2 Greentech Media, 2015.

Case Study: Impact of Block Size on BOS

Case: 65MW Plant with 5 nos. Of 10MW

and 1 no. of 15MW Block Feeder

ComparisonforuseofvariousTransformerwindingoptions(5Nos.of10MWFeeders&1No.of15MWFeeder)

S.No Parameter Case1 Case3

Inverter Roomwith2Inverters&3WindingTransformer(1No.)

Inverter Roomwith4Inverters&5WindingTransformer(1No.)

1 DesignType 2.5MVABlockwith3-windingXmer 5MVABlockwith5-windingXmer

3 No.ofInverterTransformers 26Nos.(2.5MVACapacity) 13Nos.(5MVACapacity)

4 No.ofAux.Transformers 26Nos.(OneAuxTrasfforeachInverter room)

13Nos.(OneAuxTrasfforeachInverter room)

5 No.ofUPS 26Nos.(OneUPSforeachInverterroom)

13Nos.(OneUPSforeachInverterroom,butsizeofUPSwillbealmosttwicecomparedtoCase1)

6 No.ofVCBs 58Nos.VCB(630A)&3Nos.VCB(1600A)

32Nos.VCB(630A)&3Nos.VCB(1600A)

7 DCPowercable(SMBtoInverterCable)

45000Mtrs(150Sqmm)&70000Mtrs(185Sqmm)

60000Mtrs(150Sqmm)&90000Mtrs(185Sqmm)

8 HTCable13650Mtrs(3Cx120Sqmm),3560Mtrs(3Cx240Sqmm),600Mtrs(3Cx300sqmm)

3950Mtrs(3Cx240Sqmm),4320Mtrs(3Cx300sqmm)

9 AuxPowerCable(3Cx1.5sqmmCu.)

22815Mtrs 31900Mtrs

10 CommunicationCable(RS485) 18590Mtrs 26050Mtrs

11 CommunicationCable(OFC) 31330Mtrs 12560Mtrs

12 HDPEPipes 49950Mtrs 38610Mtrs

13 No.ofPEBInverterRooms(PreEngineered Building)

26 13

14 SizeofeachInverter Room(Approx)

8.5mx6m 14.5mx6m

15 Transformer foundation 26Nos. 13Nos.

16 CCTV 32Nos.ofHDPTZtype&7Nos.ofHDFixedtype

19Nos.ofHDPTZtype&7Nos.ofHDFixedtype

Item Savings(INR/W)

1. Tranformers +Aux.+UPS

0.06

2. Switchgear 0.25

3. Cables(Power+Aux.+Communication)

0.08

4. CivilWork 0.06

Saving of INR 0.45/W due to

Block Size Increase and use

of 5-winding Transformer

“”

1500V Inverter

Advantages

• Higher DC and AC voltage i.e. lesser current and lesser cabling

• Lesser current allows the increase in inverter block power, lesser BOS

• 50% longer strings, implying lesser strings, and 33% lesser junction boxes

• Lesser monitoring, and economical installation

• IEC certifications are in place

• Higher yield

Disadvantages

• Component availability limited at present, thus driving BOS costs higher

• Higher inverter costs due to 1500V components

1500V v/s 1000V

Comparison of 1500V v/s 1000VItem Remarks Savings(%) Savings

(INR/Wp)SavingTrend

PVModules 0.5USDcentshigherfor1500V -1.15% -0.34

DCCables

Quantity Saving~30%UnitCostconsidered10%extrafor1500V 22.22% 0.16

SCB

Quantity Saving~32%UnitCostconsidered25%extrafor1500V 15.70% 0.05

ACSubsystemInverter Trafo,LTCable, Aux.Trafo 11.44% 0.08

Inverter25%highercost

-25.00% -0.44

Civil&Labour

InverterPadfor1500V,Roomfor1000V.InstallationLabourworkreductionby10%assumed 31.08% 0.22

Overall -0.83% -0.28

1500V v/s 1000V

Comparison of 1500V v/s 1000V (Alternate Optimization)

• For same DC ohmic losses, a 7.5MW block can be formed in 1500V when

compared to 5MW block

• Bigger block size would mean optimization can be carried on AC side

1500V7.5MW

1000V5MW

Land

• The cost of land for solar projects has risen about 6-10 times as compared to 2010-11

• Not only expensive, but difficulties in acquisition

• As the cost of PV modules decrease, land use optimization by decreasing the

tilt, and increasing the power density (kW/sqm)

East-West Mounting• For places closer to equator, i.e. latitude <10°, solar modules can be mounted

in east west fashion at low tilt angles (around 3°)

• High land utilization, with GCR>80% can be achieved

• Wider peak

• Lesser structure and foundation cost• Lesser BOS cost

• Marginal drop in generation

East-West Mounting

-11.98%

-14.47%

-11.55%-12.15%

-11.08% -10.98% -11.12%

-7.68%

-4.22% -3.90% -4.31% -4.26% -3.70% -3.81%-4.81%

-3.72%-2.62%

-1.73%30.16 28.59 26.84 24.97 23.76 23.07 22.31 22.36 21.32 18.52 17.38 14.66 14.29 13.14 11.87 9.9 9.36 8.36

GEN

ERATIONRED

UCTION%

LATITUDE

EastWest Mounting v/s South Facing

Shift from Fixed to Seasonal – How numbers work

• 20 X 315Wp modules in series = 6.3kWp = 1 Table

• 1MWp = 160 Tables (approx.)

• A team of 3 persons will take 15 minutes to change tilt of 1 table

(on an average), hence, 32 tables per day.

• Five such teams i.e 15 persons per day shall be able to change

tilt of 1MWp installation.

• At a labour rate of Rs. 350/- per day, it takes less than Rs. 6000

to change tilt of 1MWp installation.

• Assuming an increment of 3T / MWp between fixed and seasonal

tilt, additional capex comes out to be Rs. 2.4Lacs approx.

Structure Trend - Seasonal Tilt - Y 2014 – 60T

S.No Description Section Size Length (m)

Tot. Quantity

Unit Weight (kg/m) Tot. Wt. (kg)

1) Column Post 130CU60x5 2.80 656 9.42 17302.66

2) Rafter 120CS50x18x3 3.375 656 5.74 12708.36

3) Purlin 130CS50x14x1.5 4.97 1312 2.96 19301.09

4) Side Bracing-1 L-55x55x5 1.28 984 4.12 5189.222

5) Side Bracing-2 L-55x55x5 1.49 656 4.12 4027.053

6) Connection plate 0.265 656 1.04 682.24

6) Connection Cleat 0.167 2624 0.157 411.968

7) SQ. Washer 0.05 3936 0.0589 231.8304

Total Structural Steel Qty. (kg) 59854.42

Say 60 Ton

Structure Trend - Seasonal Tilt - Y 2015 – 40T

Module Mounting Structural Steel Qty.

Description Sectional Details

Quantity /Table

Grade of Steel Finish Length

(m)Unit. Wt(Kg/m)

Component wt. (kg)

Quantity/MW

Total Wt(Kg)

Column 120CU50x3.15 5 350 Mpa GAL 2.390 5.10 12.189 835 10177.82Washer Plate PLT 50x50x5 10 250 Mpa GAL 0.050 1.96 0.098 1670 163.87Rafter 100CU50x2 5 350 Mpa GAL 2.910 3.00 8.730 835 7289.55Purlin (A) 70CS40x15x1.2 4 350 Mpa GAL 3.460 1.61 5.576 668 3724.63Purlin (B) 70CS40x15x1.2 4 350 Mpa GAL 5.195 1.61 8.372 668 5592.32Purlin (C) 70CS40x15x1.2 4 350 Mpa GAL 3.460 1.61 5.576 668 3724.63Side Bracing-1 40CU40x2 5 350 Mpa GAL 1.270 1.75 2.223 835 1855.79Side Bracing-2 40CU40x2 5 350 Mpa GAL 1.470 1.75 2.573 835 2148.04Connection Plate-1 330x100x4

5250 Mpa GAL

0.330 3.1401.036 835 865.23

Connection Plate-2 265x100x4

5250 Mpa GAL

0.265 3.1400.832 835 694.80

Connection angle L PLT 70x70x3 20 250 Mpa GAL 0.110 3.23 0.355 3340 1185.23Tie Rod 12mm dia 8 250 Mpa GAL 0.965 0.889 0.858 1336 1145.99

Total Weight Per MW 38567.89Spare 3 % 1157.04

Say 40 Ton

Pre Fab rooms and Decking Sheets

• Pre fab rooms offer significant time advantages in execution timelines

hence bring generation gains and more efficient supplies

• Instances where Pre fab buildings are not considered, decking sheets with

concrete layer on top can offer same benefits. It provides both required

strength, insulation and quicker installation benefits

Wind Shielding of Outer most structures

• Recent designs leverage on the density of array yard and consider lower

values of k2 factor in design calculations of structures.

• Outer rows are designed with higher sections as they have more impact of

wind speeds, however inner rows are designed 10-15% lighter to leverage

the shielding that outer structure provides

The 0.8mm Galvalume! In Sub 30 T structures!

One name that has echoed in procurement teams lately.

It’s a fine play and tight walk on the line between Optimization and Under design

Galvalume suits fixed tilt structures and can be very good for optimization

Use of galvalume in seasonal tilt structures has seen many failures recently and

resulted in loss of PV modules & of course generation

Extra caution to be exercised while tilting galvalume based structures and must

be done only using proper jacks. Manual tilting is a strict no, if not particularly

addressed during Engineering

Cost Saving by Internal Transmission Line

Site specific: If land is not highly constrained, and HT cables are running along northern boundary

Pros:

• Cheaper compared to HT cable (30-40% lesser at full load evacuation)

• Maintenance friendly, and lesser probability of fault

• Higher current carrying capacity. New age AAAC panther conductors can carry

25MW on single circuit, whereas typical 33kV cables will take around15MW

Cons:

• Land wastage around poles due to shadow

• Land wastage can be minimized by planning TL along boundary, and suitably

oriented to north direction

Future Trends

Main Drives of BOS Cost Reduction in future• Best practices assimilation across the industry

• Module efficiency

• Technological developments

• Incremental design improvements, such as higher overloading, mounting

structure, block size, etc• Localization including streamlined logistics

• Increase in market volume

• Automation in production, development and installation

Based on the above factors and historical trends, we foresee a BOS cost reduction of 30%-35% by 2020

About Gensol

Gensol, found in 2007 is India’s leading Advisory and System Integrator for Solar

PV Power Projects. Gensol is a channel partner to MNRE and enjoys

empanelment with most major Lending Institutions in India.

2,500+ MW 12,000+ kW

Gensol has an advisory portfolio of

more than 2.5 GW with every 5th MW

in India developed with our expertise.

Being an MNRE Channel partner,

Gensol has executed more than 12

MW of Solar Rooftop Projects across

India.

Gensol is based out of Ahmedabad in

Gujarat but has operational solar

projects across 16 Indian States.

With a 130+ Employee Strength –

Gensol prides itself on having the

best technical talent in industry.

AWARDS

BusinessWorld – India’s largest

weekly business magazine awarded

Gensol with “Hottest Young

Entrepreneur” in 2009.

Economic Times – India’s largest

financial daily awarded Gensol in its

“Power of Ideas” series in 2010.

Gensol was the only non-UK based

firm to be nominated for Global

Consultancy of the Year at

BusinessGreen Leader Awards,

London in 2014.

Gensol Engineering Pvt Ltd | Gensol Consultants Pvt Ltd

Corporate Office108, Pinnacle Business ParkOpp Royal Arcade, PrahladnagarAhmedabad, GujaratIndia - 380015

Email: solar@gensol.inWebsite: www.gensol.inPhone: +91 79 40068235Fax: +91 79 40068239Twitter: gensol_tweets

Gensol is one of the leading consultants and system integrators for Solar Power Plants. We boast of a portfolio of over

2500 MW of Solar Photovoltaic Plants. Gensol is also a channel partner to Ministry of New & Renewable Energy and

installs kW scale Solar Rooftop systems on a turnkey basis with more than 15 MW of cumulative installations across the

country.

The information contained herein is of a general nature and is not intended to address the circumstances of any particular

individual or entity. Although we endeavor to provide accurate and timely information, there can be no guarantee that such

information is accurate as of the date it is received or that it will continue to be accurate in the future. No one should act on

such information without appropriate professional advice after a thorough examination of the particular situation.