outdoor characterization of bifacial modules at hanwha q...

Outdoor characterization of bifacial modules at Hanwha Q CELLS | Confidential | D. Buss et al. | BifiPV WS 2018, Denver | September 20181

OUTDOOR CHARACTERIZATION OF BIFACIAL MODULESAT HANWHA Q CELLS

BifiPV Workshop 2018, 10th September, Denver, CO

Hanwha Q CELLS GmbH

Dominik Buß, Evelyn Herzog, Christoph Scholz, René

Zimmermann, Björn Eisenhawer


WHO WE ARE

O V E R V I E W

Hanwha Q CELLS Co., Ltd. (NASDAQ: HQCL) is the largest cell manufacturer and one of the largest solar

module manufacturers in the world.

MANUFACTURING FACILITIES

Manufacturing Plants in 3 countries

(South Korea, Malaysia and China)

Spanning Europe, North America, Asia, South

America, Africa and the Middle East

40+ SALES NETWORK

South Korea (Global Executive HQ)

and Germany (Technology &

Innovation HQ)

HEADQUARTERS TECHNOLOGY LEADERSHIP

R&D Centers in 4 countries

(Germany, South Korea, Malaysia

and China)

As of Q1, 2018

CELL AND

MODULE

PRODUCTION

CAPACITY OF

OUR PRODUCT RANGE

MODULESKITS &

BUNDLES

POWER

PLANTS

8+ GW

ABOUT HANWHA Q CELLS


OUTLINE

1. MOTIVATION

2. REAR SHADING & MISMATCH

3. LONG TIME ENERGY YIELD

4. SUMMARY & RESULTS


1. MOTIVATION

- Influences on bifacial energy yield gain -

BIFACIAL

ENERGY

YIELD

Albedo: Reflectivity of

ground

Rear shading Distance to ground

Location & weatherOrientation & tilt angle

External influences which effect the energy output of bifacial systems

Mounting system &

Ground coverage ratio


1. MOTIVATION

- Approach & questions -

Approach here:

As a starting point, put bifacial modules in a “monofacial” system

design

Two questions:

• Shading in monofacial systems leads to serious mismatch.

Is rear shading & mismatch a serious problem, too?

• Which bifacial energy yield gain can be expected?


OUTLINE

1. MOTIVATION






- Introduction-

1000 W/m² 10 A

0

5

10

0

500

1000

Cu

rre

nt [A

]

Irra

dia

tio

n [W

/m²]

Irradiation & Current in Bifacial module

Bifa gain

Variations in rear side contribution are small compared to total current



- Mismatch introduction-

Vmpp

Impp

MPP

IstringOP

Pmax

Pout

0

100

200

300

0

5

10

15

0 15 30 45

Po

we

r [W

]

Cu

rre

nt [A

]

Voltage [V]

Mismatch introduction

I [A] MPP

Operation point Power [W]

Mismatch loss

Mismatch losses arise at operation at non-optimal current/voltage

Mismatch losses come on top of the optical shading losses



- Instrument module -

Features of 72 cells instrument module

Special instrument module for spatially resolved irradiation measurements

Front side:

3 cells to measure

front side irradiation

Rear side:

Spatially resolved

irradiation measurement

Data visualisation:

Rear irradiation w/ respect

to front side irradiation



- Rear irradiation along a string -

Approach

• Existing PV-System

• Move Instrument module along the string

and measure rear irradiation



- Rear illumination along a string -

7%

9%

11%

13%

1 7 13 19 25 31 37

Re

ar

vs.

fro

nt irra

dia

itio

n

Distance to table end [Cell columns]

Rear side irradiance by distance to table endVertical bars

• Rear side irradiation decreases with increasing distance from frame end

• Average rear shading factor: 8%

Module

table

en

d

Mid

dle

of

module

table



- Worst case simulation-

-4%

-3%

-2%

-1%

0%

1%

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21

Mis

ma

tch

lo

ss [%

]

Mismatch in Submodules

Mismatch losses for different string configurations

MM in string (7 / 0)







0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

Fu

lly r

ea

r sh

ad

ed

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

Fu

lly r

ea

r sh

ad

ed

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

Fu

lly r

ea

r sh

ad

ed

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

Fu

lly r

ea

r sh

ad

ed

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

Fu

lly r

ea

r sh

ad

ed

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

Fu

lly r

ea

r sh

ad

ed

Partially rear shaded Bifa string:

MM in particular module < 4% depending on ratio unshaded/shaded


-0.2

-1.4

-4.0

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

100% 86% 71% 57% 43% 29% 14% 0%

Mis

ma

tch

lo

ss [%

]

Fraction of unshaded Bifa modules in partially shaded string

Total mismatch losses in bifacial string around 0.2 % (only mounting structure shading)

Worst case mismatch losses in string are 1.4% (for moderate rear irradiation*)


- Worst case simulation-

* around or below 10% of front contribution

Mismatch for different unshaded/shaded Bifa-String configurations


OUTLINE

1. MOTIVATION






- Long term track record -

Long term measurements in

realistic mounting scenario

Field configuration• Modules placed within module row

• Other rows in front and back

• Row distance: 5.9 m / GCR = 34%

• Orientation: South, 30°

• Height over ground: 1.2 m

• Grass ground

• Bifaciality: 60%

Compare Measurements to PVSYST-

Simulation• Version 6.6.7

• Albedo: 25%

• Rear shading factor: 8%

• Bifaciality: 60%

• Rear mismatch loss: 2.2%

0.2% total MM equals 0.2% / 9%

= 2.2% rear MM

5.9 m


0

5

10

15

20

0

50

100

150

200

2502

01

7-0

7

20

17

-08

20

17

-09

20

17

-10

20

17

-11

20

17

-12

20

18

-01

20

18

-02

20

18

-03

20

18

-04

20

18

-05

20

18

-06

20

18

-07

20

18

-08

Bifa

cia

l g

ain

[%

]

Mo

nth

ly I

rra

dia

tio

n[k

Wh/m

²]

IrradiationSum Gain Bifa HC transparent Simulated Bifa gain 5.9m


- Long term track record -

Comparsion of measured to simulated bifacial energy yield gain

• Total measured gain: 9%

• Total simulated gain 8%

• Generally good fit, weather conditions led to variant Albedo


OUTLINE

1. MOTIVATION






- Summary -

RESULTS

Significant bifacial energy yield gains can be achieved even under non-

optimized conditions (here: 9% p.a.)

Mismatch due to rear shading is only a minor problem (<1.4% MM loss) for

moderate* rear side irradiation

Simulation in the right order of magnitude but in tendency conservative due to

Albedo variances (Snow / yellowed grass)

* around or below 10% of front irradiation


BACKUP

BACKUP



- Shading bar in varying distance -

-8%

-6%

-4%

-2%

0%

0 10 20 30 40

Lo

ss [%

]

Distance of obstacle to rear side [cm]

Losses by distance

Loss of rear side irradiance compared to homogeneous illumination (9%)

Total irradiance loss (front+rear)

Mismatch loss

Total Power loss

Experiment: Varying distance of shading bar

to rear side

• shading bar: 6 cm x 10 cm

• short side facing module rear



- Shading bar in varying distance -

(*) around 10% of front irradiation

-1.0%

-0.8%

-0.6%

-0.4%

-0.2%

0.0%

-9% -8% -7% -6% -5% -4% -3% -2% -1% 0%

Lo

sse

s [%

]

Rear side shading [%]

Total irradiance loss (front+rear) Mismatch loss Total power loss

Mismatch behaves nearly linear under moderate(*) rear irradiation and shading

Losses as function of rear shading



- Introduction -

• Inverter MPPT controls string current to global MPP

• Each module in string is operated at this current

0

1000

2000

0

2

4

6

8

10

12

0 100 200 300

Po

we

r [W

]

Cu

rre

nt [A

]

Voltage [V]

IV-Curve of string and single module

Module 7 IV-Curve

Module 1 IV-Curve

String IV-Curve

String MPP

Operating Point

Impp

Pmodule string



- Introduction -

Mismatch loss due to operation of module with beyond-MPP current

261.2 W

272.0 W

0

100

200

300

0

2

4

6

8

10

12

0 10 20 30 40 50

Po

we

r [W

]

Cu

rre

nt [A

]

Voltage [V]

IV-Curve of string and single moduleModule 7 IV-Curve

String IV-Curve

Module MPP

Operating Point

Impp

Module Power

Module MPPvoltage

Operating voltage

Operating power

Module MPPpower

outdoor characterization of bifacial modules at hanwha q...

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