Solar Bankability Improving the attractiveness of solar PV...

Funded by the Horizon 2020

Framework Programme of the

European Union

Creating a cost-based Failure Modes and Effects

Analysis (FMEA) for PV

David Moser, EURAC

Solar Bankability

Improving the attractiveness of solar PV

investmentsFinal public workshop, Brussels, 7-8 February 2017

2

Modules …. …. …. …. ….

Inverter …. …. …. …. ….

Mounting structure …. …. …. …. ….

Connection &

distribution boxes

…. …. …. …. ….

Cabling …. …. …. …. ….

Potential equalization &

grounding, LPS

…. …. …. …. ….

Weather station,

communication,

monitoring

…. …. …. …. ….

Infrastructure &

environmental influence

…. …. …. …. ….

Storage system …. …. …. …. ….

Miscellaneous …. …. …. …. ….

Product Development Assessment of PV Plants

List of failures

Product

testingPlanning

Transportation

/ installationO&M Decommissioning

Technical Risks Matrix

• Insulation test

• Incorrect cell

soldering

• Undersized bypass

diode

• Junction box

adhesion

• Delamination at the

edges

• Arcing spots on the

module

• Visually detectable

hot spots

• Incorrect power rating

(flash test issue)

• Uncertified

components or

production line

• Soiling

• Shadow diagram

• Modules mismatch

• Modules not certified

• Flash report not

available or incorrect

• Special climatic

conditions not

considered (salt

corrosion, ammonia,

...)

• Incorrect assumptions

of module

degradation, light

induced degradation

unclear

• Module quality unclear

(lamination, soldering)

• Simulation parameters

(low irradiance,

temperature….)

unclear, missing PAN

files

• Module mishandling

(glass breakage)


(cell breakage)


(defective backsheet)

• Incorrect connection

of modules

• Bad wiring without

fasteners

• Hotspot

• Delamination

• Glass breakage

• Soiling

• Shading

• Snail tracks

• Cell cracks

• PID

• Failure bypass diode

and junction box

• Corrosion in the

junction box

• Theft of modules

• Module degradation

• Slow reaction time for

warranty claims, vague

or inappropriate

definition of procedure

for warranty claims

• Spare modules no

longer available, costly

string reconfiguration

• Undefined product

recycling procedure

3

Modules …. …. …. …. ….

Inverter …. …. …. …. ….


Connection &

distribution boxes

…. …. …. …. ….

Cabling …. …. …. …. ….


grounding, LPS

…. …. …. …. ….

Weather station,

communication,

monitoring

…. …. …. …. ….

Infrastructure &


…. …. …. …. ….




List of failures

Product

testing


• Insulation test

• Incorrect cell

soldering

• Undersized bypass

diode

• Junction box

adhesion

• Delamination at the

edges

• Arcing spots on the

module

• Visually detectable

hot spots

• Incorrect power rating

(flash test issue)

• Uncertified

components or

production line

Uncertainty

4

Modules …. …. …. …. ….

Inverter …. …. …. …. ….


Connection &

distribution boxes

…. …. …. …. ….

Cabling …. …. …. …. ….


grounding, LPS

…. …. …. …. ….

Weather station,

communication,

monitoring

…. …. …. …. ….

Infrastructure &


…. …. …. …. ….




List of failures

Planning


• Soiling

• Shadow diagram






conditions not

considered (salt

corrosion, ammonia,

...)


of module

degradation, light

induced degradation

unclear




(low irradiance,

temperature….)


files

Uncertainty

5

Modules …. …. …. …. ….

Inverter …. …. …. …. ….


Connection &

distribution boxes

…. …. …. …. ….

Cabling …. …. …. …. ….


grounding, LPS

…. …. …. …. ….

Weather station,

communication,

monitoring

…. …. …. …. ….

Infrastructure &


…. …. …. …. ….




List of failures

Planning


• Soiling

• Shadow diagram






conditions not

considered (salt

corrosion, ammonia,

...)


of module

degradation, light

induced degradation

unclear




(low irradiance,

temperature….)


files

Uncertainty

6

Modules …. …. …. …. ….

Inverter …. …. …. …. ….


Connection &

distribution boxes

…. …. …. …. ….

Cabling …. …. …. …. ….


grounding, LPS

…. …. …. …. ….

Weather station,

communication,

monitoring

…. …. …. …. ….

Infrastructure &


…. …. …. …. ….




List of failures

Planning


• Soiling

• Shadow diagram






conditions not

considered (salt

corrosion, ammonia,

...)


of module

degradation, light

induced degradation

unclear




(low irradiance,

temperature….)


files

Uncertainty

7

Modules …. …. …. …. ….

Inverter …. …. …. …. ….


Connection &

distribution boxes

…. …. …. …. ….

Cabling …. …. …. …. ….


grounding, LPS

…. …. …. …. ….

Weather station,

communication,

monitoring

…. …. …. …. ….

Infrastructure &


…. …. …. …. ….




List of failures

Transportation

/ installation



(glass breakage)


(cell breakage)


(defective backsheet)

• Incorrect connection

of modules

• Bad wiring without

fasteners

Precursors

8

Modules …. …. …. …. ….

Inverter …. …. …. …. ….


Connection &

distribution boxes

…. …. …. …. ….

Cabling …. …. …. …. ….


grounding, LPS

…. …. …. …. ….

Weather station,

communication,

monitoring

…. …. …. …. ….

Infrastructure &


…. …. …. …. ….




List of failures

O&M

Technical Risk Matrix

• Hotspot

• Delamination

• Glass breakage

• Soiling

• Shading

• Snail tracks

• Cell cracks

• PID


and junction box


junction box





or inappropriate


for warranty claims




Quantifiable impact

9

Modules …. …. …. …. ….

Inverter …. …. …. …. ….


Connection &

distribution boxes

…. …. …. …. ….

Cabling …. …. …. …. ….


grounding, LPS

…. …. …. …. ….

Weather station,

communication,

monitoring

…. …. …. …. ….

Infrastructure &


…. …. …. …. ….




List of failures

O&M

Technical Risk Matrix

• Hotspot

• Delamination

• Glass breakage

• Soiling

• Shading

• Snail tracks

• Cell cracks

• PID


and junction box


junction box





or inappropriate


for warranty claims




Indirect impact

Classification of technical risks

10

Year 0 risks

Risk MatrixProduct

testingPlanning

Transportation

/ installationO&M Decommissioning


Uncertainty Precursors

Quantifiable impact

Indirect impact

Impact

- on uncertainty (exceedance Probability)

- on CAPEX

- on CPN (O&M)

• Risks to which we can assign a Cost Priority Number CPN

(e.g. module and inverter failure) given in Euros/kWp/year

Impact on cash flow

• Risks to which we can assign an uncertainty (e.g. irradiance)

Impact on financial exceedance probability parameters

Quantification of the economic impact of

technical risks

11

O&M

Planning

-9

-8

-7

-6

-5

-4

-3

-2

-1

0

1

2

3

4

5

6

7

4.55%5.07%

20 y sat GTI

5.80%

+10.91%

6.45%

site adaptation

sat GTI

5 y meas GHI DiffHI

13.41%

transp model

5 y sat GHI DiffHI

10.57%10.04%

5 y meas GTI

9.53%

site adaptation GHI DiffHI

base scenario (20 y sat

GHI DiffHI)

8.70%

14.89%

+11.04%

5 y sat GTI

+26.87%

-21.55%

-10.08%

+9.54%

20 y meas GHI and

DiffHI

-25.86%

6.61%

20 y meas GTI


Impact on financial exceedance probability parametersPlanning

132/10/2017

σ (k=1) P50 (kWh/kWp) P90 (kWh/kWp)P90/P50 (P50

reference case)

Ref. case (sum of

squares) 8.7% 1445 1283 89%

Low end scenario 4.6% 1445 1365 94%

High end scenario 9.3% 1445 1273 88%

Worst case scenario 16.6% 1445 1138 79%

Worst case scenario

(different mean value) 16.6% 1314 1034 72%

22% difference in terms of yield used in the business model

Objectives:

- More precise estimation of

uncertainty in yield estimation

- Reduction of uncertainty


Impact on financial exceedance probability parametersPlanning

14

a) Economic impact due to downtime and/or power loss (kWh

to Euros)

- Failures might cause downtime or % in power loss

- Time is from failure to repair/substitution and should include:

time to detection, response time, repair/substitution time

- Failures at component level might affect other components

(e.g. module failure might bring down the whole string)

b) Economic impact due to repair/substitution costs (Euros)

- Cost of detection (field inspection, indoor measurements,

etc)

- Cost of transportation of component

- Cost of labour (linked to downtime)

- Cost of repair/substitution

Income reduction

Savings reduction

Increase in

maintenance costs

Reduction of

reserves

• Risks to which we can assign a Cost Priority Number CPN

(e.g. module and inverter failure) given in Euros/kWp/year

Impact on cash flow

O&M

Procedure for the calculation of CPNs

1510/20/201

6

Risks to which we can assign a CPN (e.g. module and inverter

failure during O&M)

1. calculation of average downtime for a specific failure of a specific component [h]

tdown,fail=(ttd + ttr/ts) x PL x M + tfix x M

PL = Power loss in %

M = Multiplier to take into account impact at higher component level

• Solar Bankability Webinar

O&M

0

ttdttr/tts tfix

hoursdaysmonths

Failures Time to detect [h] Time to repair/substitution [h] Repair/substitution time [h] Power loss [%] Multiplier

Hotspot 8760 744 2 2,00% 1

Delamination 8760 744 2 1,00% 1

Glass breakage 8760 744 2 10,00% 1

Soiling 8760 744 0,01 10,00% 1

Shading 8760 744 0,01 10,00% 1

Snail track 8760 744 2 1,00% 1

Cell cracks 8760 744 2 1,00% 1

Defective backsheet 8760 744 2 1,00% 1

Overheating junction box 8760 744 2 1,00% 1

PID = Potential Induced

degradation8760 744 2 10,00% 1

Failure bypass diode and

junction box8760 744 2 33,00% 1

Corrosion in the junction box 8760 744 2 1,00% 1

EVA discoloration 8760 744 0 0,0% 1

Theft of modules 8760 744 0,5 100,00% 1

Broken module 8760 744 2 100,00% 1

Damage by snow 8760 744 2 100,00% 1

Corrosion of cell connectors 8760 744 2 1,00% 1

Unsufficient theft protection 8760 744 2 0,00% 1

Improperly installed 8760 744 2 5,00% 1

Module damaged due to fire 8760 744 0,5 100,00% 1

Missing modules 8760 744 2 100,00% 1


16


failure during O&M)

2.calculation of total downtime for the n number of components failures over a certain

period [h/year] tdown = tdown,fail x nfail

3.calculation of total downtime normalised by components [h/year]

tdown,comp = tdown/ncomp

4.calculation of PL related occurrence over a time tref [fraction or % of components]

OCPN = tdown,comp/tref

tref could be either the equivalent hours (specific yield), the total number of hours per

year or the number of sun hours. Occurrence can thus be considered as the energy loss

in % caused by a specific failure over a certain period

O&M

Modules Delamination 16 16045 1961147

Modules Cell cracks 8 916 1961147

Modules Snail track 11 28975 1961147

Component Failures No. Tickets No. Cases No. Components

nfail ncomp


17


failure during O&M)

5. calculation of production losses, L, due to downtime [kWh]

L = OCPN x SCPN

The severity, SCPN, is calculated as the total plant(s) production over one year [kWh]

6.calculation of downtime costs as missing production/savings in Euros/period or

Euros/kWp/period

Cdown = L x (FIT+PPA+RCE)

For the calculation of the costs due to downtime, it is important to consider the missing

income of feed in tariffs, the missing income from PPA, and/or the missing savings

generated by PV plants installed on roofs/facades. RCE:Retail Cost of Electricity

O&M

Methodology allows for geographical

analysis and differentiation for

PV plant typology and market segment


18


failure during O&M)

7. The costs related to fixing the failure results from the sum of the costs of

repair/substitution, costs of detection, costs of transport and cost of labour

Cfix = (Cdet + Crep/sub + Ctransp) x nfail + Clab x tfix x nfail

8. The calculation of the Cost Priority Number is then given by CPN = Cdown + Cfix

O&M

Methodology allows for the inclusion of the cost of detection Cdetttd

Failures

Rm (average cost of

detection/component) [€]

Rsu (average substitution cost

/component or unit) [€]

Rr (average repair

cost/component) [€]

Rp (average transport costs per

component) [€]

Hotspot 0,00 € 108,00 € 0,00 € 10,00 €

Delamination 0,00 € 108,00 € 0,00 € 10,00 €

Glass breakage 0,00 € 108,00 € 0,00 € 10,00 €

Soiling 0,00 € 0,00 € 0,26 € 10,00 €

Shading 0,00 € 0,00 € 0,08 € 10,00 €

Snail track 0,00 € 108,00 € 0,00 € 10,00 €

Cell cracks 0,00 € 108,00 € 0,00 € 10,00 €

Defective backsheet 0,00 € 108,00 € 0,00 € 10,00 €

Overheating junction box 0,00 € 108,00 € 0,00 € 10,00 €

PID = Potential Induced

degradation 0,00 € 108,00 € 0,00 € 10,00 €

Failure bypass diode and

junction box 0,00 € 108,00 € 0,00 € 10,00 €

Corrosion in the junction box 0,00 € 108,00 € 0,00 € 10,00 €

EVA discoloration 0,00 € 0,00 € 0,00 € 0,00 €

Theft of modules 0,00 € 108,00 € 0,00 € 10,00 €

Broken module 0,00 € 108,00 € 0,00 € 10,00 €

Damage by snow 0,00 € 108,00 € 0,00 € 10,00 €

Corrosion of cell connectors 0,00 € 108,00 € 0,00 € 10,00 €

Unsufficient theft protection 0,00 € 0,00 € 0,00 € 0,00 €

Improperly installed 0,00 € 0,00 € 0,00 € 0,00 €

Module damaged due to fire 0,00 € 108,00 € 0,00 € 10,00 €

Missing modules 0,00 € 108,00 € 0,00 € 10,00 €

Cdet Csub CtranspCrep

https://upload.wikimedia.org/wikipedia/commons/6/6e/Brass_scales_with_cupped_trays.png

Technical Risks collection

19• Solar Bankability Webinar

O&M

CPN = Cdown + Cfix

CPN is given in Euros/kWp/year

It gives an indication of the economic impact of a failure

due to downtime and investment cost

Tickets from O&M operators

as corrective or periodic maintenance

in paper or electronic form

Visual and

detailed inspection

Technical Risks collection

20

- Do all failures have a relevant economic impact?

- Are data biased? Location / Technology / Monitoring system

O&M

Biased – site was surveyed due to a reported problem

Unbiased – site was surveyed as part of routine maintenance

Extrapolated – Only a part of the plant was surveyed and data extrapolated

CPN = Cdown + Cfix

CPN is given in Euros/kW/year

It gives an indication of the economic impact of a failure

due to downtime and investment cost

Total number of plants Total Power [kWp] Average number of years

TOTAL 772 441676 2.7

Components No. tickets No. Cases No. Components

Modules 473 678801 2058721

Inverters 476 2548 11967

Mounting structures 420 15809 43057

Connection & Distribution boxes 221 12343 20372

Cabling 614 367724 238546

Transformer station & MV/HV 53 220 558

Total 2257 1077445 2373222

Definition of scenarios

21

• Never detected (CPNndet)

Failure is undetected. Losses due to downtime over a time ttd

• Failure fix (CPNfailfix)

Failure is detected. 1 Month of lead time to repair/substitution

• Failures are equally distributed over time

• No increase in Performance Losses over time

• Yield is considered as an average at national level (not site specific)

• The real scenario would be a combination of the two

O&M

0 12

0 121

ttd

ttr/tts

tfix

CPN Results - Components and Market Segments

22

• PV modules - Utility scale

• Highest risk consists of a group of installation failures (mishandling, connection

failures, missing fixation, etc. )

• Variety of failures detected by different techniques (VI, IR, EL, IV-Curves)

Technical Risks collection: some statistics

23

O&M

no. cases no. components YearsShare of failures/

year

Modules 678,640 2,058,721 2.68 33% 12%

Inverters 2,474 11,967 2.68 21% 8%

Module Failure share

Soiling 23.4%

Shading 16.8%

EVA discoloration 11.6%

Glass breakage 6.5%

PID 5.0%

Inverter Failure share

Fan failure and overheating 21.8%

Fault due to grounding issues 4.9%

Inverter firmware issue 3.8%

Burned supply cable and/or

socket2.2%

Polluted air filter 3.3%

Inverter pollution 1.5%

OCPN from the cost-based FMEA

CPN results - Components and market segments

24

• PV modules – All market segments

O&M

~60 Euros/kW/y

Who bears the cost?

Who bears the risk?

CPN results - Comparison studies

2510/20/201

6

• Worst scenario vs base scenario for modules (higher PL)

O&M

ΣCPNndet= ~ 11 Euros/kWp/y

ΣCPNndet= ~ 19 Euros/kWp/y


26

• Affected components vs total components: CPN ratio

O&M

Failures calculated over the whole

database

Failures calculated over the affected

plants


27

• Influenced components vs total components

Defined as CPN ratio

• High CPN ratio for product failures or non technical factors

O&M

0.08 €/kWp/y 34 €/kWp/y

6 €/kWp/y 114 €/kWp/y

Conclusions

28

- Standardised nomenclature of failures

- Methodology to calculate the economic impact of technical risks

- Methodology can be used to assess the effectiveness of mitigation measures

- Basis for the determination of risk scenarios

O&MPlanning

- More precise estimation of

uncertainty in yield

estimation

- Reduction of uncertainty

- First cost-based FMEA in the

PV sector (CPN)

Funded by the Horizon 2020

Framework Programme of the

European Union

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 649997.

The content of this report reflects only the author’s view and the Commission is not responsible for any use that may be made of the information it contains

Thank you!

• David Moser (Eurac)

Date post:	12-Jun-2020
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Solar Bankability Improving the attractiveness of solar PV...

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