Options and Recommendation on PV Module Product Scope

Transcription

1 Options and Recommendation on PV Module Product Scope Prepared for: Prepared by: Quantis Dr. Michael Spielmann Managing Director Germany Lettemieke Mulder Independent Consultant November 12, 2015

2 TABLE OF CONTENT 1 INTRODUCTION PHOTOVOLTAIC STANDARDS, GUIDANCE DOCUMENTS PV MODULE AND SYSTEM PRODUCT SPECIFICATION & DEFINITION MODULE: SPECIFICATIONS AND DEFINITIONS BALANCE OF SYSTEM: SPECIFICATIONS & DEFINITIONS PERFORMANCE EVALUATIONS: LIFETIME EXPECTANCY OF MODULES DEFINITION AND SPECIFICATION OPTIONS ON PV MODULE PRODUCT SCOPE PRODUCT SCOPE SPECIFICATIONS UL 1703 PRODUCT SCOPE SPECIFICATIONS PRODUCT SCOPE DEFINITION IN THE CONTEXT OF THE PEF INITIATIVE PRODUCT SCOPE DEFINITIONS ACCORDING TO IEA LIFE CYCLE INVENTORIES AND LIFE CYCLE ASSESSMENT OF PHOTOVOLTAIC SYSTEMS GUIDANCE DOCUMENT FUNCTIONAL UNIT/REFERENCE FLOW DEFINITION ADEME PEF INITIATIVE CRE SCOPE OF TECHNOLOGIES IEA LIFE CYCLE INVENTORIES AND LIFE CYCLE ASSESSMENT OF PHOTOVOLTAIC SYSTEMS GUIDANCE DOCUMENT PEF INITIATIVE ADEME: RECOMMENDATIONS FOR PRODUCT SCOPE DEFINITIONS November 12, 2015 Page 2

3 1 Introduction This task includes summarizing options for the PV module product scope in terms of technologies, functional unit, and if applicable, product specifications, thereby aligning with existing industry standards. This paper is structured as follows: In section 2, an overview of existing industry standards (mainly testing standards), environmental standards and guidance documents are presented. In section 3, PV system specifications and definitions available from existing standards and reports are summarized. Options for defining the product scope are outlined in section 4. This also includes definitions of functional unit. Finally, recommendations for product scope definitions are outlined and discussed in section 5. Assumptions on the context: In line with the expectations laid out by the Green Electronics Council, a leadership standard for solar PV panels should include measurable criteria for multiple levels of environmental leadership achievement and performance throughout the lifecycle of the product. It should also addresses multiple attributes and environmental performance categories including but not limited to energy demand, carbon footprint, management of substances, efficient material use, design for recycling, responsible end-of-service/end-of-life management, longevity, life cycle assessments, and corporate responsibility. Implications for the product scope definitions: Life Cycle Assessment definitions must be part of the product scope definitions. This includes the definitions of a functional unit. Design and product longevity may also be part of the standard to be developed. Thus, references to performance evaluation testing standards are required. For PV systems, there are various established technologies in the market and some are in development. This may lead to differences in environmental profiles and reduction measures for products. 2 Photovoltaic Standards, Guidance Documents Definitions of scope as well as Module are available from the following sources: UL 1703 FLAT-PLATE PHOTOVOLTAIC MODULES AND PANELS 1 IEC Standards for design qualification and type approval of CRYSTALLINE SILICON TERRESTRIAL PHOTOVOLTAIC (PV) MODULES (IEC61215) 2 ; THIN-FILM TERRESTRIAL November 12, 2015 Page 3

4 PHOTOVOLTAIC (PV) MODULES (ICE 61646) 3 and Concentrator Photovoltaic (CPV) Modules and Assemblies (IEC 62108) 4 IEC Standard for PHOTOVOLTAIC (PV) MODULE SAFETY QUALIFICATION (IEC 61730) 5 Product Environmental Footprint (PEF) Initiative, Draft Product Environmental Product Footprint Category Rules (PEFCR). 6 IEA Life Cycle Inventories and Life Cycle Assessment of Photovoltaic Systems 7 ISO Environmental management -- Life cycle assessment -- Requirements and guidelines ADEME Methodological framework for assessing the environmental impacts of photovoltaic systems using the life cycle assessment method of the French Environment and Energy Management Agency (ADEME) CRE Cahier des charges de l appel d offres portant sur la réalisation et l exploitation d installations de production d électricité à partir de techniques de conversion du rayonnement solaire d une puissance supérieure à 100 kwc et situées dans les zones non interconnectées) 8 3 PV Module and System Product Specification & Definition Photovoltaic module is frequently used as general term for panels (framed modules) and laminates (unframed module). The following system components must be defined and addressed when determining the product scope for a PV leadership standard: Module (including frame if needed) Balance of System (BOS) 3.1 Module: Specifications and Definitions Two comprehensive specifications of a module can be found in existing standards: ion 7 R. Frischknecht, R. Itten, P. Sinha, M. de Wild-Scholten, J. Zhang, V. Fthenakis, H. C. Kim, M. Raugei, M. Stucki, 2015, Life Cycle Inventories and Life Cycle Assessment of Photovoltaic Systems, International Energy Agency (IEA) PVPS Task 12, Report T12-04: This document defines requirements for the calculation of GHG-emissions in appendix 4 of the tender document. November 12, 2015 Page 4

5 1. UL 1703 defines a module as the smallest environmentally protected, essentially planar assembly of solar cells and ancillary parts, such as interconnects and terminals, intended to generate DC power under unconcentrated sunlight. The structural (load-carrying) member of a module can either be the top layer (superstrate), or the back layer (substrate), in which: a) The superstrate is the transparent material forming the top (light-facing) outer surface of the module. If load-carrying, this constitutes a structural superstrate. b) The substrate is the material forming the back outer surface of a module. If load-carrying, this constitutes a structural substrate 2. In PEF Initiative, a module is defined as A photovoltaic module basically consists of 48, 60 or 72 photovoltaic cells (156 x 156 mm crystalline technology), or a semiconductor layer (thin film technology), a substrate and a cover material (glass, plastic films), the connections (used for the interconnection of the cells), the cabling (used for the interconnection of the modules) and the frame (in case of panels). 3.2 Balance of System: Specifications & Definitions The Balance of System (BOS) equipment typically varies with the installation of PV-systems: IEA distinguishes between roof top PV applications and ground-mounted PV installations. For a rooftop PV installations, the BOS typically includes the following parts: inverters, mounting structures, cable and connectors. Large-scale ground-mounted PV installations require additional equipment and facilities such as: grid connections, office facilities, and concrete. In the next section some examples of existing standards are presented. 3.3 Performance Evaluations: Lifetime Expectancy of Modules Definition and Specification The actual lifetime expectancy of modules depends on their design, their environment and the conditions under which they are operated. Three separate International Standards (IEC-standards) lay down IEC requirements for the design qualification and type approval of terrestrial photovoltaic modules suitable for long-term operation in general open-air climates, as defined in IEC A standard for crystalline silicon modules types and a standard for thin-film modules and a standard for concentrator photovoltaic (CPV) Modules and Assemblies have been published as IEC 61215, IEC 61646, and IEC respectively. November 12, 2015 Page 5

6 The object of the test sequence is to determine the electrical and thermal characteristics of the module and to show, as far as is possible within reasonable constraints of cost and time, that the module is capable of withstanding prolonged exposure in climates described in the scope. 4 Options on PV Module Product Scope 4.1 Product Scope Specifications In this section examples on product scope specifications are presented. These examples are drawn from the standards listed above UL 1703 Product Scope Specifications UL 1703 (FLAT-PLATE PHOTOVOLTAIC MODULES AND PANELS) is sometimes referred to as the gold standard for safety in the U.S. It is the basis for the IEC document, which is the international safety standard. UL 1703 requirements cover flat-plate photovoltaic modules and panels intended for installation on or integral with buildings, or to be freestanding (that is, not attached to buildings), in accordance with the National Electrical Code, NFPA 70, and Model Building Codes. These requirements cover modules and panels intended for use in systems with a maximum system voltage of 1000 V or less. These requirements also cover components intended to provide electrical connection to and mounting facilities for flat-plate photovoltaic modules and panels. UL 1703 requirements do not cover: a) Equipment intended to accept the electrical output from the array, such as power conditioning units (inverters) and batteries; b) Any tracking mechanism; c) Cell assemblies intended to operate under concentrated sunlight; d) Optical concentrators; or e) Combination photovoltaic-thermal modules or panels Product Scope Definition in the Context of the PEF Initiative 9 In line with the specifications in section 3.1, the term photovoltaic module is used as general term for panels (framed modules) and laminates (unframed module). The scope of the PEFCR is the production of DC electricity with photovoltaic modules. The product category corresponds to the production of photovoltaic modules used in photovoltaic power systems for electricity generation. 9 Status It should be noted that the PEFCR development is work in progress and thus the scope may be changing. November 12, 2015 Page 6

7 PEF follows the classical Life Cycle Assessment approach and hence includes the manufacturing, the operation and dismantling and recycling of material during the end- of-life phase of the photovoltaic modules as well as the use of production equipment and facilities and the supply chain of the materials used. Mounting is considered as part of the product. Not considered in the product scope are balance of system components such as inverter and AC cabling (connection to the grid) Product Scope Definitions according to IEA Life Cycle Inventories and Life Cycle Assessment of Photovoltaic Systems guidance document IEA follows the classical Life Cycle Assessment approach and hence includes the manufacturing, the operation and dismantling and recycling of material during the end- of-life phase of the photovoltaic modules as well as the use of production equipment and facilities and the supply chain of the materials used. It also includes the mounting as part of the product system as well as other balance of system components such as inverter and AC cabling (connection to the grid). 4.2 Functional Unit/Reference Flow Definition The terms functional unit and reference flow are defined in ISO A comprehensive analysis of functional unit definitions used in the context of LCA evaluation is available from the PEF initiative ADEME The basic function of the PV installations analyzed using the methodological framework is electricity production. The functional unit of the LCA must relate to the function of the system analyzed and is used to compare the results of different electricity-generating PV systems. It is therefore: 1 kwh generated by a photovoltaic system during its lifespan and either exported to the grid (distribution or transmission) or consumed Consumed energy means energy consumed on-site by electric appliances, when operating within a contractual arrangement to sell any surplus capacity to the grid. This useable consumed energy does not include losses through the internal electricity network nor any consumption by ancillary functions of the photovoltaic installation (e.g. monitoring). To carry out the environmental analysis of the technological process characterized by this functional unit it is necessary to estimate the PV system potential estimation. This estimate should take into account the technical characteristics of the installation being studied (i.e. module yield, electricity losses, PV system lifespan, etc.) as well as the irradiation at the PV system location. November 12, 2015 Page 7

8 The environmental impacts of the PV system can be calculated either by using the system's nominal power or the effective surface area of the PV field related to the kwh (the functional unit in the framework) PEF Initiative Based on this comprehensive analysis the following definitions have been made: The functional unit (unit of analysis 10 ) is defined as 1 kwh (kilo Watt hour) of DC electricity generated by a photovoltaic module. The reference flow is the photovoltaic module, measured in kwp (Kilowatt peak), the maximum power output of a module. The functional unit defined according to the following four criteria listed in the PEF Guide. The function(s) / service(s) provided ( what ): DC electrical energy measured in kwh (provided power times unit of time) at the outlet of the DC connector attached to the junction box of the PV module The magnitude of the function or service ( how much ) 1 kwh of DC electrical energy The expected level of quality ( how well ) DC electrical energy at the photovoltaic panel at a given voltage level. The amount of service provided over the lifetime ( how long ) DC electrical energy at the photovoltaic panel during the service life of 30 years CRE The functional unit of the simplified carbon footprint analysis is defined as 1kWp of PV modules. The respective reference flows of included materials are as follows: Polysilicon in kg. This value is reduced to the mass of silicon contained in 1 kwp module. Ingots in kg silicon. This value is reduced to the mass of silicon contained in 1 kwp module. Wafers in number of wafers. This amount is reduced to the number of wafers needed to make 1 kwp. Losses and breakages are neglected. (The reference value contribution is based on the actual size and the actual thickness of wafers (wafer reference size: 156 x 156 mm, thickness 190 microns)). Cells in number of cells. This value is the number of cells required to make 1 kwp. Losses and breakages are neglected. 10 According to PEF terminology the term unit of analysis is used in the PEF context as a synonym for functional unit as used in ISO November 12, 2015 Page 8

9 The contribution may be reduced to the actual cell size (reference wafer 156 x 156 mm). Modules in m² modules. This value is the module area needed to make 1 kwp whether for crystalline modules or thin film. Glass in kg. This value is the mass of glass needed to make 1 kwp so reduced to the surface and the thickness of glass (reference density of 2700 kg/m3). Tempered glass in kg. This value is the mass of tempered glass to make 1 kwp (so returned to the surface and thickness of the tempered glass, reference density 2700 kg / m3). EVA in kg. This value is the mass of EVA needed to make 1 kwp (so reduced to the surface and the thickness of EVA, reference density 963 kg/m3). PET in kg. This value is the mass of PET required to make 1 kwp (so reduced to the surface and the thickness of PET, reference density 1400 kg/m3). PVF in kg. This value is the mass of PVF required to make 1 kwp (so reduced to the surface and thickness of the PVF, reference density 1400 kg/m3). The simplified carbon footprint is calculated for 1 kwp of module without the frame limited to the components listed above. Further specifications: The calculations are based on the electricity mix of the country regardless of the actually electricity supply contract. Savings linked to the recycling of the complete module at the end of life cannot be considered in the carbon footprint calculation. Process inefficiencies are neglected. (e.g. breakage and yield loss). 4.3 Scope of Technologies For PV systems various technologies are established and/or are in development. This may lead to differences in environmental profiles and reduction measures for the different products. More than 85 % of the PV modules (GWp, the maximum power output of the modules) produced in 2012 (globally) were crystalline silicon of which 53 % were multi-crystalline and 47 % monocrystalline % of the production was thinfilm modules with CdTe having the largest share, followed by amorphous/micromorphous modules FHI-ISE (2013) Photovoltaics report. Fraunhofer Institue (FHI) for Solar Energy System (ISE), Freiburg, Germany, cited from from draft PEFCR published in the PEF initiative. November 12, 2015 Page 9

10 4.3.1 IEA Life Cycle Inventories and Life Cycle Assessment of Photovoltaic Systems Guidance Document It is stated that consensus is limited to five technologies for which there are well-established and upto-date LCI data: mono- and multi-crystalline Si, CdTe, CIGS, and high concentration PV (HCPV) using III/V cells PEF Initiative Within the PEF initiative five different photovoltaic technologies are differentiated: mono-si, multi- Si, a-si / μm-si, CdTe and CIGS ADEME Single-crystal silicon and thin-film technologies are singled out in the ADEME framework; all other technologies are classified as undefined technologies. 5 Recommendations for Product Scope Definitions Based on an assessment of the different scope definitions, we would recommend the current PEF initiative of the European Commission as the preferable starting point for product scope definition. The reasons for this recommendation are: The development of this standard is led by an international group of PV-manufacturers and environmental experts in the PV sector: IEA PVPS Task 12, EPIA, PVthin The International Thin-Film Solar Industry Association, Yingli Solar, First Solar, Total, Calyxo, ECN and Treeze. It allows for the inclusion of all established technologies and specifies system boundaries, data requirements and provide default data for each technology. In the future it may become an established standard for LCA calculations in the PV sector and thus following an existing standard would reduce the workload for manufacturers. There are however also a few points to be considered related to this choice: The PEF initiative focuses on further specifying ISO for the PV-sector. While for developing a leadership standard, Life Cycle Assessment will be an important tool, following the PEF methodology may result in some aspects not being highlighted. For instance: If, in the development of the leadership standard, no comparison with other power generating system is strived for (which is to be decided), we would recommend narrowing the scope to the module and frame (if required). In this case, installation would be out of the scope and no BOS components would be included. The exclusion of equipment intended to accept the electrical output from the array; such as power conditioning units (inverters) and batteries should be explicitly mentioned. Such simplification would also allow using the maximum power output of a module (kw p ) as a functional unit, an approach which is also suggested by CRE. Product longevity is an aspect, which may have to be addressed separately and may also make reference to existing testing standards as listed above. With respect to technologies, ideally the standard should include all technologies. It is important though to check whether testing procedures and environmental information are November 12, 2015 Page 10

11 available to allow for fair comparison. As a minimum, the new leadership standard should include crystalline silicon (multi-crystalline and mono-crystalline) and thin-film modules. On the other hand, it should be noted in practice also 125mm x 125mm cells are available. This should be taking into account for the definition/specification of modules. November 12, 2015 Page 11