IEA INTERNATIONAL ENERGY AGENCY 
PHOTOVOLTAIC POWER SYSTEMS PROGRAMME 
No data, no performance 
the importance of monitoring 
Wilfried van Sark, Utrecht University 
Solar Event 
7 October 2014, Den Bosch, NL
IEA INTERNATIONAL ENERGY AGENCY 
PHOTOVOLTAIC POWER SYSTEMS PROGRAMME 
Content 
•! Motivation 
•! Work from IEA-PVPS-Task 13 
–! Example: performance Italy 
–! Example: data from web scraping 
•! Specific yield determination in the 
Netherlands 
•! Task 13 reports
IEA INTERNATIONAL ENERGY AGENCY 
PHOTOVOLTAIC POWER SYSTEMS PROGRAMME 
Motivation 
•! PV is becoming a mainstream 
energy harvesting option 
135 GWp power, end 2013 
1 GWp in the Netherlands 
•! Optimal performance is required 
•! But, do we know 
“How well is PV serving the world?” 
Without DATA we cannot address PERFORMANCE 
Task 13: Performance and Reliability of PV systems
IEA INTERNATIONAL ENERGY AGENCY 
PHOTOVOLTAIC POWER SYSTEMS PROGRAMME 
International Energy Agency of the 
PV Power Systems Programme 
•! 29 members: 24 countries, EC, EPIA, 
SEPA, SEIA, Copper Alliance 
•! Most recent member: Thailand 
•! Activities are carried out collaboratively on 
a country basis along a number of 
technical and non-technical subjects 
•! Currently, 6 Tasks are active 
www.iea-pvps.org
IEA INTERNATIONAL ENERGY AGENCY 
PHOTOVOLTAIC POWER SYSTEMS PROGRAMME 
Present IEA PVPS Tasks 
•! Task 1 - Exchange and dissemination of information on PV power systems 
•! Task 2 - Operational performance, maintenance and sizing of PV power systems and 
subsystems (concluded 2008) 
•! Task 3 - Use of PV power systems in stand-alone and island applications (concluded 2004) 
•! Task 5 - Grid interconnection of building integrated and other dispersed PV systems 
(concluded 2001) 
•! Task 6 - Design and operation of modular PV plants for large scale power generation 
(concluded 1997) 
•! Task 7 - PV power systems in the built environment (concluded 2001) 
•! Task 8 - Very large scale PV power generation systems 
•! Task 9 - Deployment of PV technologies: co-operation with developing countries 
•! Task 10 - Urban Scale PV Applications (concluded 2009) 
•! Task 11 - PV hybrid systems within mini-grids (2013: combined with Task 9) 
•! Task 12 - PV environmental, health & safety activities 
•! Task 13 - PV performance, quality and reliability (2014 - 2017) 
•! Task 14 - High-penetration of PV systems in electricity grids (2014 - 2017)
IEA INTERNATIONAL ENERGY AGENCY 
PHOTOVOLTAIC POWER SYSTEMS PROGRAMME 
Relevant PVPS Issues 
•! Scenario work 
•! Market development and trends 
•! Policy framework 
•! Business models 
•! New technologies and applications 
•! Urban and rural implementation 
•! Large scale deployment 
•! Environmental aspects 
•! Quality and reliability 
•! Grid integration
IEA INTERNATIONAL ENERGY AGENCY 
PHOTOVOLTAIC POWER SYSTEMS PROGRAMME 
Task 13: Performance and Reliability 
of Photovoltaic Systems 
ST 1: Economics of PV System Performance 
and Reliability 
ST 2: System Performance and Analysis 
ST 3: Module Characterisation and 
Reliability 
ST 4: Dissemination
IEA INTERNATIONAL ENERGY AGENCY 
PHOTOVOLTAIC POWER SYSTEMS PROGRAMME 
Task 13: Analysis of PV System Performance 
DATABASE
IEA INTERNATIONAL ENERGY AGENCY 
PHOTOVOLTAIC POWER SYSTEMS PROGRAMME 
Task 13: Performance Ratio over Time 
Installed Location Range of PR Avg. PR 
1980s Worldwide 0.50 - 0.75 Individual 
estimates 
1990s Worldwide 0.25 - 0.90 0.66 
1990s Worldwide 0.50 - 0.85 0.65 - 0.70 
1990s Germany 0.38 - 0.88 0.67 
2000s France 0.52 - 0.96 0.76 
2000s Belgium 0.52 - 0.93 0.78 
2000s Taiwan <0.3 - >0.9 0.74 
2000s Germany 0.70 - 0.90 0.84
IEA INTERNATIONAL ENERGY AGENCY 
PHOTOVOLTAIC POWER SYSTEMS PROGRAMME 
Performance is going up 
Performance ratio 
IEA – PVPS Task 2 
[Nordmann, 2007] 
PR from ~60% to >80% 
[Reich, 2012] 
90% max?!
IEA INTERNATIONAL ENERGY AGENCY 
PHOTOVOLTAIC POWER SYSTEMS PROGRAMME 
Motivation 
•! Performance has been increasing in the past decades 
•! Still, reasons for lower 
performance than expected 
(or promised) are difficult to 
detect, due to insufficient 
monitoring (in particular 
1-5 kWp residential systems)
IEA INTERNATIONAL ENERGY AGENCY 
PHOTOVOLTAIC POWER SYSTEMS PROGRAMME 
Statistical analysis Italy 
•! Example size bin: 10-100 kWp, installed in 2007, full year 
measurements for 2008-2012 (5 years) 
•! Courtesy: Francesca Tilli (GSE)
IEA INTERNATIONAL ENERGY AGENCY 
PHOTOVOLTAIC POWER SYSTEMS PROGRAMME 
Italy 
All years averaged 
Larger systems 
somewhat better 
performing 
# systems 
North: 58 
Central: 48 
South: 48
IEA INTERNATIONAL ENERGY AGENCY 
PHOTOVOLTAIC POWER SYSTEMS PROGRAMME 
Data mining 
•! Market is introducing web 
tools for system owners to 
share monitor data, e.g., 
SolarLog 
•! Objective is to analyze PV 
performance data 
obtained by web scraping 
techniques that collect and 
organize these data 
automatically in databases 
•! “What you see, is what you 
can extract” 
•! Developed Python scripts 
(Panos Moraitis)
IEA INTERNATIONAL ENERGY AGENCY 
PHOTOVOLTAIC POWER SYSTEMS PROGRAMME 
Results 
Country Samples System Size kWp 
Netherlands 728 11.1 
Germany 764 15.6 
Italy 532 13.1 
France 325 15.1 
Belgium 565 6.5 
GER ITA NL FRA BEL 
P 
M 
A
IEA INTERNATIONAL ENERGY AGENCY 
PHOTOVOLTAIC POWER SYSTEMS PROGRAMME 
Results 
•! Yearly variation between 2011-2013 from 2-11% 
2011 
2012 
2013 
NL GER BEL ITA FRA
IEA INTERNATIONAL ENERGY AGENCY 
PHOTOVOLTAIC POWER SYSTEMS PROGRAMME 
South: 
+6-18% 
FRA GER ITA 
Annual yield (kWh/kWp) ±(stdev) 
Country 2011 
2012 2013 
Germany 
North 979±153 937±126 882±109 
South 1081±154 1044±121 992±125 
France 
North 1030±362 993±201 959±154 
South 1099±96 1092±224 1103±166 
Italy 
North 1219±170 1177±157 1094±148 
South 1352±113 1337±199 1288±203
IEA INTERNATIONAL ENERGY AGENCY 
PHOTOVOLTAIC POWER SYSTEMS PROGRAMME Results: NL Geographical Variation 
Region PR Annual Yield kWh/ 
kWp 
Irradiation kWh/ 
kWp 
Coast 79.3+/-2% 895+/-21 1165 
Mainland 77.1+/-2% 833+/-19 1021 
Temperature, wind ?
IEA INTERNATIONAL ENERGY AGENCY 
PHOTOVOLTAIC POWER SYSTEMS PROGRAMME 
Task 13: Statistics on the Operation of PV Systems 
AIM: Energy Yield-GIS or PR-GIS?
IEA INTERNATIONAL ENERGY AGENCY 
PHOTOVOLTAIC POWER SYSTEMS PROGRAMME 
Determination of standard 
specific yield in the Netherlands 
•! Statistics Netherlands (CBS) annually publishes the 
amount of installed capacity of photovoltaic systems: 
722 MWp, end 2013 [1 GWp, mid september 2014] 
•! PV generated electricity is calculated from the installed 
capacity using a full-load-hours model: the average 
capacity of the year is multiplied with 700 h, 
equivalent with specific annual yield: 700 kWh/kWp 
•! Renewal of protocol is necessary: PV systems in the 
Netherlands now are producing much than 700 kWh/ 
kWp according to market stakeholders 
! DATA needed to prove that 
•! Expert work group advice, open source data, installer 
data (representing ~2% of installed capacity)
IEA INTERNATIONAL ENERGY AGENCY 
PHOTOVOLTAIC POWER SYSTEMS PROGRAMME 
Dutch performance data 
2012 
877 kWh/kWp 
2013 
874 kWh/kWp 
Advice: 875 kWh/kWp (25% increase!), starting 
from 2011 
! Presently, PV contributes 0.5% to electricity supply in 
the Netherlands (and increasing)
IEA INTERNATIONAL ENERGY AGENCY 
PHOTOVOLTAIC POWER SYSTEMS PROGRAMME 
Conclusions 
•! Obviously, without DATA one 
cannot say anything on 
PERFORMANCE 
•! IEA PVPS Task 13, subtask 2 
•! Collecting and analyzing data 
–! From all participating countries 
–! Statistical analysis, web scraping 
•! Want to contribute?
IEA INTERNATIONAL ENERGY AGENCY 
PHOTOVOLTAIC POWER SYSTEMS PROGRAMME 
Thank you for listening! 
Q&A 
http://www.iea-pvps.org/index.php?id=57
IEA INTERNATIONAL ENERGY AGENCY 
PHOTOVOLTAIC POWER SYSTEMS PROGRAMME 
Part 2: IEA PVPS Task 13 
http://www.iea-pvps.org/index.php?id=57 
1.!Review of Failures of Photovoltaic Module, Report IEA-PVPS T13-01:2014 
2.!Analytical Monitoring of Grid-connected Photovoltaic Systems - Good Practices for 
Monitoring and Performance Analysis, Report IEA-PVPS T13-03: 2014 
3.!Characterisation of Performance of Thin-film Photovoltaic Technologies, Report IEA-PVPS 
T13-02:2014 
4.!Degradation Behaviour of PV Modules under Different Accelerated Stress Conditions 
Based on Stress Conditions Evaluated from Real-time Outdoor Testing, Report IEA-PVPS 
T13-04: 2014 
5.!Analysis of Long-Term Performance of PV Systems - Different Data Resolution for 
Different Purposes,, Report IEA-PVPS T13-05:2014
IEA INTERNATIONAL ENERGY AGENCY 
PHOTOVOLTAIC POWER SYSTEMS PROGRAMME 
Global co-operation towards 
sustainable deployment of PV power systems 
9th Task 13 Expert Meeting in Freiburg, Germany, 
April 2014
IEA INTERNATIONAL ENERGY AGENCY 
PHOTOVOLTAIC POWER SYSTEMS PROGRAMME

Wilfried van Sark, Utrecht University: No data, no performance - the importance of monitoring

  • 1.
    IEA INTERNATIONAL ENERGYAGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME No data, no performance the importance of monitoring Wilfried van Sark, Utrecht University Solar Event 7 October 2014, Den Bosch, NL
  • 2.
    IEA INTERNATIONAL ENERGYAGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME Content •! Motivation •! Work from IEA-PVPS-Task 13 –! Example: performance Italy –! Example: data from web scraping •! Specific yield determination in the Netherlands •! Task 13 reports
  • 3.
    IEA INTERNATIONAL ENERGYAGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME Motivation •! PV is becoming a mainstream energy harvesting option 135 GWp power, end 2013 1 GWp in the Netherlands •! Optimal performance is required •! But, do we know “How well is PV serving the world?” Without DATA we cannot address PERFORMANCE Task 13: Performance and Reliability of PV systems
  • 4.
    IEA INTERNATIONAL ENERGYAGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME International Energy Agency of the PV Power Systems Programme •! 29 members: 24 countries, EC, EPIA, SEPA, SEIA, Copper Alliance •! Most recent member: Thailand •! Activities are carried out collaboratively on a country basis along a number of technical and non-technical subjects •! Currently, 6 Tasks are active www.iea-pvps.org
  • 5.
    IEA INTERNATIONAL ENERGYAGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME Present IEA PVPS Tasks •! Task 1 - Exchange and dissemination of information on PV power systems •! Task 2 - Operational performance, maintenance and sizing of PV power systems and subsystems (concluded 2008) •! Task 3 - Use of PV power systems in stand-alone and island applications (concluded 2004) •! Task 5 - Grid interconnection of building integrated and other dispersed PV systems (concluded 2001) •! Task 6 - Design and operation of modular PV plants for large scale power generation (concluded 1997) •! Task 7 - PV power systems in the built environment (concluded 2001) •! Task 8 - Very large scale PV power generation systems •! Task 9 - Deployment of PV technologies: co-operation with developing countries •! Task 10 - Urban Scale PV Applications (concluded 2009) •! Task 11 - PV hybrid systems within mini-grids (2013: combined with Task 9) •! Task 12 - PV environmental, health & safety activities •! Task 13 - PV performance, quality and reliability (2014 - 2017) •! Task 14 - High-penetration of PV systems in electricity grids (2014 - 2017)
  • 6.
    IEA INTERNATIONAL ENERGYAGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME Relevant PVPS Issues •! Scenario work •! Market development and trends •! Policy framework •! Business models •! New technologies and applications •! Urban and rural implementation •! Large scale deployment •! Environmental aspects •! Quality and reliability •! Grid integration
  • 7.
    IEA INTERNATIONAL ENERGYAGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME Task 13: Performance and Reliability of Photovoltaic Systems ST 1: Economics of PV System Performance and Reliability ST 2: System Performance and Analysis ST 3: Module Characterisation and Reliability ST 4: Dissemination
  • 8.
    IEA INTERNATIONAL ENERGYAGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME Task 13: Analysis of PV System Performance DATABASE
  • 9.
    IEA INTERNATIONAL ENERGYAGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME Task 13: Performance Ratio over Time Installed Location Range of PR Avg. PR 1980s Worldwide 0.50 - 0.75 Individual estimates 1990s Worldwide 0.25 - 0.90 0.66 1990s Worldwide 0.50 - 0.85 0.65 - 0.70 1990s Germany 0.38 - 0.88 0.67 2000s France 0.52 - 0.96 0.76 2000s Belgium 0.52 - 0.93 0.78 2000s Taiwan <0.3 - >0.9 0.74 2000s Germany 0.70 - 0.90 0.84
  • 10.
    IEA INTERNATIONAL ENERGYAGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME Performance is going up Performance ratio IEA – PVPS Task 2 [Nordmann, 2007] PR from ~60% to >80% [Reich, 2012] 90% max?!
  • 11.
    IEA INTERNATIONAL ENERGYAGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME Motivation •! Performance has been increasing in the past decades •! Still, reasons for lower performance than expected (or promised) are difficult to detect, due to insufficient monitoring (in particular 1-5 kWp residential systems)
  • 12.
    IEA INTERNATIONAL ENERGYAGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME Statistical analysis Italy •! Example size bin: 10-100 kWp, installed in 2007, full year measurements for 2008-2012 (5 years) •! Courtesy: Francesca Tilli (GSE)
  • 13.
    IEA INTERNATIONAL ENERGYAGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME Italy All years averaged Larger systems somewhat better performing # systems North: 58 Central: 48 South: 48
  • 14.
    IEA INTERNATIONAL ENERGYAGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME Data mining •! Market is introducing web tools for system owners to share monitor data, e.g., SolarLog •! Objective is to analyze PV performance data obtained by web scraping techniques that collect and organize these data automatically in databases •! “What you see, is what you can extract” •! Developed Python scripts (Panos Moraitis)
  • 15.
    IEA INTERNATIONAL ENERGYAGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME Results Country Samples System Size kWp Netherlands 728 11.1 Germany 764 15.6 Italy 532 13.1 France 325 15.1 Belgium 565 6.5 GER ITA NL FRA BEL P M A
  • 16.
    IEA INTERNATIONAL ENERGYAGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME Results •! Yearly variation between 2011-2013 from 2-11% 2011 2012 2013 NL GER BEL ITA FRA
  • 17.
    IEA INTERNATIONAL ENERGYAGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME South: +6-18% FRA GER ITA Annual yield (kWh/kWp) ±(stdev) Country 2011 2012 2013 Germany North 979±153 937±126 882±109 South 1081±154 1044±121 992±125 France North 1030±362 993±201 959±154 South 1099±96 1092±224 1103±166 Italy North 1219±170 1177±157 1094±148 South 1352±113 1337±199 1288±203
  • 18.
    IEA INTERNATIONAL ENERGYAGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME Results: NL Geographical Variation Region PR Annual Yield kWh/ kWp Irradiation kWh/ kWp Coast 79.3+/-2% 895+/-21 1165 Mainland 77.1+/-2% 833+/-19 1021 Temperature, wind ?
  • 19.
    IEA INTERNATIONAL ENERGYAGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME Task 13: Statistics on the Operation of PV Systems AIM: Energy Yield-GIS or PR-GIS?
  • 20.
    IEA INTERNATIONAL ENERGYAGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME Determination of standard specific yield in the Netherlands •! Statistics Netherlands (CBS) annually publishes the amount of installed capacity of photovoltaic systems: 722 MWp, end 2013 [1 GWp, mid september 2014] •! PV generated electricity is calculated from the installed capacity using a full-load-hours model: the average capacity of the year is multiplied with 700 h, equivalent with specific annual yield: 700 kWh/kWp •! Renewal of protocol is necessary: PV systems in the Netherlands now are producing much than 700 kWh/ kWp according to market stakeholders ! DATA needed to prove that •! Expert work group advice, open source data, installer data (representing ~2% of installed capacity)
  • 21.
    IEA INTERNATIONAL ENERGYAGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME Dutch performance data 2012 877 kWh/kWp 2013 874 kWh/kWp Advice: 875 kWh/kWp (25% increase!), starting from 2011 ! Presently, PV contributes 0.5% to electricity supply in the Netherlands (and increasing)
  • 22.
    IEA INTERNATIONAL ENERGYAGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME Conclusions •! Obviously, without DATA one cannot say anything on PERFORMANCE •! IEA PVPS Task 13, subtask 2 •! Collecting and analyzing data –! From all participating countries –! Statistical analysis, web scraping •! Want to contribute?
  • 23.
    IEA INTERNATIONAL ENERGYAGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME Thank you for listening! Q&A http://www.iea-pvps.org/index.php?id=57
  • 24.
    IEA INTERNATIONAL ENERGYAGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME Part 2: IEA PVPS Task 13 http://www.iea-pvps.org/index.php?id=57 1.!Review of Failures of Photovoltaic Module, Report IEA-PVPS T13-01:2014 2.!Analytical Monitoring of Grid-connected Photovoltaic Systems - Good Practices for Monitoring and Performance Analysis, Report IEA-PVPS T13-03: 2014 3.!Characterisation of Performance of Thin-film Photovoltaic Technologies, Report IEA-PVPS T13-02:2014 4.!Degradation Behaviour of PV Modules under Different Accelerated Stress Conditions Based on Stress Conditions Evaluated from Real-time Outdoor Testing, Report IEA-PVPS T13-04: 2014 5.!Analysis of Long-Term Performance of PV Systems - Different Data Resolution for Different Purposes,, Report IEA-PVPS T13-05:2014
  • 25.
    IEA INTERNATIONAL ENERGYAGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME Global co-operation towards sustainable deployment of PV power systems 9th Task 13 Expert Meeting in Freiburg, Germany, April 2014
  • 26.
    IEA INTERNATIONAL ENERGYAGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME