Collection of Ongoing International Standardization Activities in the Area of OLAE
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Generally, standards are requirements or recommendations based on best practices and are created by bringing together the experience and expertise of diverse groups of interested parties – the manufacturers, sellers, buyers, users and regulators of a particular material, product, process or service. This site focuses on the activities related to standardisation of measurement protocols for Organic and Large Area Electronic devices, more specifically: Organic Photovoltaics (OPV), Organic Light Emitting Diodes/Lighting (OLED/Lighting) and Organic Thin Film Transistors (OTFT).
OPV
The International Electrotechnical Commission (IEC), the Institute of Electrical and Electronics Engineers (IEEE), ASTM International (originally known as the American Society for Testing and Materials) and Underwriters Laboratories Inc. (UL) all publish standards for photovoltaic (PV) products.
Standardized protocols for performance testing in terms of efficiency and stability are defined according to IEC and ASTM norms and are specifically adapted to well-established PV technologies like crystalline silicon and amorphous silicon for professional outdoor use. Adapted protocols for emerging and novel PV technologies like OPV are not existing yet. Main efforts that have started and are still ongoing are focusing on measurement protocols for determination of the efficiency and stability of OPV devices.
Efficiency
Accurate determination of the photovoltaic power conversion efficiency is essential for a comparison of results and product compatibility. Photovoltaic device efficiencies are notoriously difficult to measure accurately because, among other reasons, of the sensitivity of the device performance to deviations between the emission spectrum of the solar simulator used in the testing and the true AM1.5 spectrum. In order to quantify the cell performance in a comparable manner, a set of Standard Reporting Conditions (SRC) has been defined. These are specified as a radiant density of 1000 W/m2 with a spectral distribution defined as “AM1.5G” (ASTM G173) at a cell temperature of 25 oC.
Standardized efficiency measurements and reference cell calibrations are carried out in photovoltaic calibration laboratories like NREL (US), FhG ISE (D), AIST (Japan) and are based on the protocols that have been developed in the US in the 1980s [ , ]. Some efforts have been made in the past to motivate and educate the research community to use these protocols (or simplified forms) for the accurate performance determination of OPV [ , , , ].An overview of maximum power conversion efficiencies for PV devices measured at “AM1.5” conditions is semi-annually published in the Solar Cell Efficiency Tables in Progress in Photovoltaics. An excerpt for OPV from the January 2009 edition is shown in Table I
Stability
The current existing tests for PV are: IEC 61215and 61646 for x-Si and thin film (a-Si) modules respectively. Internationally accepted (accelerated) ageing tests have not yet been established for organic-based solar cells, which is understandable considering the stage of development of these cells. At this stage of development of OPV, individual accelerated lifetime tests are carried out to identify critical stress factors as well as determination of acceleration factors when subjected to certain stress factors. A recent example of a setup for studying stability and degradation of polymer solar cells was published by Krebs et al.[ ] The intention of these tests is to study the performance as a function of materials, compositions, processing schemes in the various processing lines with the aim to find material combinations that permit long-term stable cells and not to define the potential lifetime that can be obtained with OPV devices under outdoor conditions. Accelerated studies may be necessary, but it is important that the exact experimental conditions are given; otherwise the results will be impossible to reproduce and interpret. Finally, results from accelerated lifetime testing cannot be viewed as generally applicable to other device geometries than the one tested as different materials and different device constitutions may give widely different responses to accelerated test conditions.
The first International Summit on Organic Photovoltaic Stability (ISOS) took place in Golden, Colorado, USA July 14-16, 2008. It was sponsored by the Department of Energy (DOE), Plextronics and the National Renewable Energy Laboratory (NREL). Suggestions for shelf-life measurements, outdoor testing, indoor accelerated light soaking, packaging/encapsulation, and determination of the stabilized efficiency were done. Conclusions of the summit can be found in a presentation that is provided here.
International Electrotechnical Commission (IEC) Technical Committee 82 Solar Photovoltaic Energy System (TC82)
The scope of TC82 is “To prepare international standards for systems of photovoltaic conversion of solar energy into electrical energy and for all the elements in the entire photovoltaic energy system.” The “dashboard” for accessing TC82 information is found here, which you can also reach by typing “82” in Search Site box at the bottom of the IEC home page (www.iec.ch) and pressing the “TC Dashboard” button. IEC TC82 comprises five working groups (covering Glossary, non-concentrating and concentrator modules, systems and balance of system components) and a joint committee working group on decentralized rural electrification.
Table 1 Positions in IEC TC82
Position Name Organization Country
TC Chairman Heinz Ossenbrink Joint Research Center European Commission
TC Secretariat Howard Barikmo
Sunset Technology USA
WG 1 (Glossary)
Convenor Hidenori Shimizu International Standards Engineering Japan
WG 2 (Modules, non-concentrating)
Convenor John Wohlgemuth
BP Solar USA
WG 3 (Systems)
Convenor Ted Spooner
Martin Cotterell University of New South Wales
Sundog Solar Australia
UK
WG 6 (Balance of System Components) Convenor Charles Whitaker
BEW Engineering USA
WG 7 (Concentrator Modules)
Convenor Robert McConnell Amonix USA
WG1 glossary: Task
To prepare a glossary.
WG2 Modules, non-concentrating: Task
To develop international standards for non-concentrating, terrestrial photovoltaic modules. These standards will be in the general areas of photoelectric performance, environmental test, quality assurance and quality assessment criteria. The standards ultimately produced should be universal and non-restrictive in their application, taking into account different environments and manufacturing technologies. In addition to the basic electrical and mechanical characteristics, standards will be written for other important factors such as module thermal performance, high voltage performance, fault resistance and fault-tolerant design.
WG3 Systems: Task
To give general instructions for the photovoltaic system design, construction and maintenance. For each particular user's application, each activity should be the object of a separate study area. The Working Group should incorporate the existing standards on the functional blocks that are different from the photovoltaic array field, and promote the production of new specific standards when necessary.
WG6 Balance-of-system components: Task
To develop international standards for balance-of-system components for PV systems. These standards will be in the general areas of performance, safety, environmental durability (reliability), quality assurance and quality assessment criteria. The standards ultimately produced should be universal and non-restrictive in their application, taking into account different environments and manufacturing technologies. In addition to the basic electrical and mechanical characteristics, standards will be written for other important factors such as thermal performance, electromagnetic interference, and climate applicability/rating.
WG7 Concentrator modules: Task
To develop international standards for photovoltaic concentrators and receivers. These standards will be in the general areas of safety, photoelectric performance and environmental reliability tests. The standards ultimately produced should be universal and non-restrictive in their application, taking into account different environments and manufacturing technologies. In addition to the basic electrical and mechanical characteristics, standards will be written for other important factors such as thermal performance, high voltage performance, fault resistance and fault-tolerant design.
A list of IEC standards can be found here.
IEC 60891, Procedures for temperature and irradiance corrections to measured I-V characteristics of crystalline silicon photovoltaic devices
IEC 60904-1, Photovoltaic devices. Part 1: Measurement of photovoltaic current-voltage characteristics
IEC 60904-2, Photovoltaic devices. Part 2: Requirements for reference solar cells
IEC 60904-2/A1, Photovoltaic devices. Part 2: Requirements for reference solar cells, Amendment 1
IEC 60904-3, Photovoltaic devices. Part 3: Measurement principles for terrestrial photovoltaic (PV) solar devices with reference spectral irradiance data
IEC 60904-4 Ed.1: Photovoltaic Devices - Part 4: Procedure for establishing the traceability of the calibration of reference solar devices
IEC 60904-5, Photovoltaic devices - Part 5: Determination of the equivalent cell temperature (ECT) of photovoltaic (PV) devices by the open-circuit voltage method
IEC 60904-6, Photovoltaic devices - Part 6: Requirements for reference solar modules
IEC 60904-6/A1, Photovoltaic devices - Part 6: Requirements for reference solar modules, Amendment 1
IEC 60904-7, Photovoltaic devices - Part 7: Computation of spectral mismatch error introduced in the testing of a photovoltaic device
IEC 60904-8, Photovoltaic devices - Part 8: Measurement of spectral response of a photovoltaic (PV) device
IEC 60904-9, Photovoltaic Devices—Part 9: Solar Simulator Performance Requirements
IEC 60904-10, Photovoltaic devices - Part 10: Methods of linearity measurement
IEC 61277, Terrestrial photovoltaic (PV) power generating systems - General and guide
IEC/PAS 62011, Specifications for the use of renewable energies in rural decentralised electrification
IEC 61215, Crystalline silicon terrestrial photovoltaic (PV) modules - Design qualification and type approval
IEC 61345, UV test for photovoltaic (PV) modules
IEC 61646, Thin-film terrestrial photovoltaic (PV) modules - Design qualification and type approval
IEC 61701, Salt mist corrosion testing of photovoltaic (PV) modules
IEC 61721, Susceptibility of a photovoltaic (PV) module to accidental impact damage (resistance to impact test)
IEC 61829, Crystalline silicon photovoltaic (PV) array - On-site measurement of I-V characteristics
IEEE SCC21 – Standards Coordinating Committee on Fuel Cells, Photovoltaics, Dispersed Generation, and Energy Storage.
SCC21 oversees the development of standards in the areas of fuel cells, photovoltaics (PV), dispersed generation, and energy storage and coordinates efforts in these fields among the various IEEE Societies and other affected organizations to ensure that all standards are consistent and properly reflect the views of all applicable disciplines. IEEE SCC21 reviews all proposed IEEE standards in these fields before their submission to the IEEE-SA Standards Board for approval and coordinates submission to other organizations. The SCC21 Official web site is found here.