Distributed Solar Quality and Safety in India - Key Challenges and Potential Solutions

July 2020July 2020

www.nrel.gov/usaid-partnership

Key Challenges and Potential Solutions

Distributed Solar Quality

and Safety in India

Authors

Arvind Karandikar, Nexus Energytech Pvt Ltd; Pune, Maharashtra, India

Ingrid Repins, Alexandra Aznar, and Carishma Gokhale-Welch, National Renewable Energy Laboratory;

Golden, CO USA

Ronnie Khanna and Devina Anand, Tetra Tech; Delhi, India

July 2020

A product of the USAID-NREL Partnership

Contract No. IAG-17-2050

Key Challenges and Potential Solutions

Distributed Solar Quality

and Safety in India

www.nrel.gov/usaid-partnership

NOTICE

This work was authored, in part, by the National Renewable Energy Laboratory (NREL), operated by Alliance for

Sustainable Energy, LLC, for the U.S. Department of Energy (DOE) under Contract No. DE-AC36-08GO28308. Funding

provided by the United States Agency for International Development (USAID) under Contract No. IAG-17-2050. The

views expressed in this report do not necessarily represent the views of the DOE or the U.S. Government, or any agency

thereof, including USAID.

This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications.

U.S. Department of Energy (DOE) reports produced after 1991 and a growing number of pre-1991 documents are available

free via www.OSTI.gov.

Prepared by

Cover photo from iStock 956955560

NREL prints on paper that contains recycled content.

Acknowledgments

The authors thank Anurag Mishra from the U.S. Agency for International Development (USAID)-India

and Sarah Lawson from the USAID Office of Energy and Infrastructure for their support of this work. We

also wish to thank the following individuals for their detailed review comments, insights, and

contributions to this report: Andy Walker, Teresa Barnes, Andrea Watson, Adam Warren (National

Renewable Energy Laboratory [NREL]), Prakhar Goel, Rakesh Kumar Goyal, Ujjwal

Bhattacharjee (Tetra Tech), Akhilesh Magal (Gujarat Energy Management Institute [GERMI]), Omkar

Jani (Kanoda Energy Systems Pvt Ltd), Anjali Garg, and Brendon Mendonca (International Finance

Corporation).

The authors would also like to acknowledge and thank Britton Marchese, Isabel McCan, Terri Marshburn,

Liz Craig, Judy Powers, Liz Breazeale, Nathan Lee (NREL), Joginder Singh, and Yogeeta Sharma (Tetra

Tech) for their editorial and design support.

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List of Acronyms

AC alternating current

BIS Bureau of Indian Standards

C&I commercial and industrial

CAPEX capital expenditure

CEA Central Electricity Authority of India

CEI Chief Electrical Inspectorate

CERC Central Electricity Regulatory Commission

CII Confederation of Indian Industry

DC direct current

Discom distribution company

DPV distributed photovoltaics

EL electroluminescence

EPC engineering, procurement, and construction

GERMI Gujarat Energy Research and Management Institute

IEC International Electrotechnical Commission

IECRE IEC System for Certification to Standards Relating to Equipment for Use in Renewable

Energy Applications

IEEE Institute of Electrical and Electronic Engineers

IIT Indian Institute of Technology

IP Intellectual Property

IP Ingress Protection

LID light induced degradation

LPS lightning protection system

MNRE Ministry of New and Renewable Energy, Government of India

MPPT maximum power point tracking

MQT module quality testing

NABCEP North American Board of Certified Energy Professionals

NEC National Electric Code

NGO nongovernmental organization

NISE National Institute of Solar Energy (India)

NREL National Renewable Energy Laboratory (U.S.A.)

NSM National Solar Mission

OD operational documents

OPEX operating expenditure

PID potential induced degradation

PPA power purchase agreement

PSU public sector unit

PV photovoltaic

QA quality assurance

QAF Quality Assurance Framework

R&D research and development

RESCO renewable energy service company

RTPV rooftop photovoltaic

SERC State Electricity Regulatory Commission

SLD single line diagram

SNA State Nodal Agency

SPD surge-protection device

TERI The Energy Resources Institute

TÜV TÜV Rhineland

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UL Underwriters Laboratories

USAID United States Agency for International Development

VRA Vendor Rating Agency

VRF Vendor Rating Framework

iii

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Executive Summary

In India, the quality and safety of solar photovoltaic (PV) systems—and their installation—have become a

concern for investors, regulators, consumers, and distribution companies (discoms). The lack of quality

standards and a push for low prices has led to the installation of poor-quality products and inferior system

design and execution on site (Devi et al. 2018). These low-quality systems deliver less energy than

expected and have a lower overall lifespan, which are serious issues for developers and investors whose

return on investment depends on the amount of power generated from these solar systems for the expected

life of the project. Equipment that does not conform to minimum quality standards also creates safety

risks for business and homeowners. Overall, both performance and safety concerns lower investor and

consumer confidence in solar products, threatening to slow market development, and are likely key

contributing factors in slowing rooftop photovoltaic (RTPV) installations in India, particularly small-

capacity systems (less than 100kW). Technical issues such as the absence of standards or monitoring

systems, and the penetration of inferior-quality products in the market hamper the performance of the

solar system and create a poor reputation for PV systems and the technology (Devi et al. 2018).

India is not alone; the solar quality and safety issues it faces mirror global experiences. Worldwide,

residential RTPV consumers are typically unable to distinguish between low- and high-quality systems.

RTPV system components vary in quality, and inadequate training leads to poor installation practices.

Many inspection checklists and certification procedures to rectify these issues are already available in

India, however, they are not always used because they are not mandatory, or the workforce is not aware

of them, or may not have the technical capacity to comply. Demonstrations of quality products and

installation practices are more effective if the information reaches the consumer in a clear way. A

successful approach to improving residential RTPV system quality is likely to include an assortment of

strategies by different stakeholders, as discussed later in this report.

This report provides solar quality and safety information and best practices that can help increase

confidence in RTPV in India, particularly for small-capacity systems, and thus accelerate the growth of

that sector. New data stemming from expert interviews and a stakeholder workshop shed light on

common quality and safety technical issues at various stages of an RTPV system’s life (Figure ES- 1) and

potential solutions for addressing them. To achieve the goal of a low-cost system with high energy yield,

best practices must be followed at each stage of system life.

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Figure ES- 1. Key RTPV quality and safety issues identified by stakeholders

Note: Common problems occur at all stages of an RTPV system’s life, as indicated by the vertical levels of the

pyramid. Issues that can result in a safety hazard or severe underproduction of energy are marked with colored

icons (see legend)

The new data and analysis are used to identify a prioritized approach to addressing the most common

RTPV issues. This approach takes the form of a quality-assurance framework comprising: 1) a Module

Quality Assurance program, 2) a Safety Quality Assurance program, and 3) a Vendor Rating Framework

(VRF) which are discussed further in Section 5 of the report. We propose that the development of a VRF

is likely the next best step to focus initial efforts to improve quality and safety of RTPV installations in

India. There are currently no mechanisms in place to monitor, evaluate, and rate vendors (engineering,

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procurement, and construction contractors or installers) in India. Establishing a VRF would help measure

the quality of systems, as well as ensure compliance of those systems to established standards. As vendors

and suppliers are held accountable for component and installation quality using this framework, a VRF

would also provide an effective mechanism to link quality systems to market share by putting in place a

procedure to evaluate, rate, and certify vendors based on their track record of designing, developing, and

deploying systems.

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Table of Contents

Executive Summary.................................................................................................................................................. iv

1 Introduction ............................................................................................................................................................ 1

1.1 Solar Energy Targets and Growth in India .............................................................................2

1.2 Key Challenges of RTPV Deployment...................................................................................2

1.3 Key Stakeholders and Their Roles in Ensuring RTPV Quality and Safety ............................3

1.4 Rooftop Solar Implementation Models and their Impact on Quality and Safety....................4

1.5 Need for Quality and Safety Standards and Implementation Framework ..............................6

2 An International Perspective: U.S. and Other Global Experiences With Solar Quality and Safety Issues.... 7

2.1 Site Inspections.......................................................................................................................7

2.2 Standards for Systems—IECRE .............................................................................................9

2.3 Education and Developing Best Practices ............................................................................10

2.4 Industry-Wide Reports on Rooftop PV Quality....................................................................11

2.5 Looking Forward—Important Conclusions and Possible Paths ...........................................11

3 Research Methodology ......................................................................................................................................... 14

3.1 Literature Review..................................................................................................................14

3.2 Stakeholder Interviews: Methodology..................................................................................15

3.3 Stakeholder Workshop..........................................................................................................15

4 Key Findings: Quality and Safety Aspects of RTPV Systems in India ............................................................ 17

4.1 RTPV Project Development Cycle .......................................................................................17

4.2 Key Challenges in RTPV Quality and Safety.......................................................................18

4.2.1 System Design-Related Quality Issues .................................................................... 19

4.2.2 Component-Related Quality Issues.......................................................................... 20

4.2.3 Installation- and O&M-Related Quality Issues........................................................ 21

4.3 Key Drivers of Poor-Quality and Unsafe Systems ...............................................................23

4.3.1 Gaps in Existing Quality Standards ......................................................................... 23

4.3.2 Focus on Capital Cost Rather Than Cost per Electrical Unit .................................. 23

4.3.3 Competition in Pricing and Speed of Work............................................................. 23

4.3.4 Lack of Training for Installers—No Eligibility Criteria.......................................... 23

4.3.5 Lack of Customer Awareness .................................................................................. 24

4.3.6 Lack of Proper Inspection During and After Installation ........................................ 24

4.3.7 Absence of Mandatory Requirements for Supervision and Audit ........................... 24

5 Prioritized Solutions and Implementation Framework for Quality and Safety Issues in RTPV................... 25

5.1.1 Module Quality Assurance ...................................................................................... 27

5.1.2

Safety Quality Assurance......................................................................................... 29

5.1.3 Vendor Rating Framework ...................................................................................... 30

6 Next Steps .............................................................................................................................................................. 34

References ................................................................................................................................................................ 35

Appendix A – Referenced Published Reports ....................................................................................................... 38

Appendix B – MNRE Published List of Standards............................................................................................... 39

Appendix C – Schematic of Key Parameters for Vendor Rating Framework ................................................... 42

Appendix D – Summary List of Issues Analyzed by RTPV Project Development Stage .................................. 43

Appendix E – Complete List of Issues and Possible Corrective Actions............................................................. 45

vii

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List of Figures

Figure ES- 1. Key RTPV quality and safety issues identified by stakeholders ............................................ v

Figure 3. Design, component procurement, and installation related quality challenges based on feedback

Figure 5. Opportunities and constraints for recommended solutions to quality and safety issues in India’s

Figure 1. Key institutions and their roles in quality and safety in solar rooftop systems in India................ 4

Figure 2. Stages in the development of a RTPV project............................................................................. 18

from stakeholders........................................................................................................................................ 19

Figure 4. Key quality and safety issues, and potential solutions. ............................................................... 26

RTPV systems............................................................................................................................................. 27

Figure 6. Implementation Framework for Module Quality Assurance....................................................... 29

Figure 7. Recommended safety quality assurance process. ........................................................................ 30

Figure 8. Process for developing and implementing a vendor rating framework....................................... 33

List of Tables

Table 1. Summary of Stages Relevant to PV-System Installation, Desired Characteristics at Each Stage,

and Standards that Describe How to Achieve these Characteristics........................................................... 10

Table 2. Desired Characteristics, Observed Problems, and Possible Solutions Based on Work at NREL

and in Literature.......................................................................................................................................... 13

Table 3. Common Findings at Various Stages of PV System Installation in India .................................... 14

Table 4. Key Quality and Safety Issues, Their Impact on Project Returns, and Potential Solutions.......... 22

Table B1. Published List of Standards........................................................................................................ 39

Table D1. Design, Component and Installation Related Quality and Safety Issues ................................... 43

Table E1. Complete List of Issues and Possible Corrective Actions.......................................................... 45

viii

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1 Introduction

In India, the quality and safety of solar PV systems—and their installation—have become concerns for

investors, regulators, consumers, and distribution companies (discoms). Apart from some existing

component-related standards, design and installation standards are either lacking or not adopted by the

Indian market. The lack of quality standards and a push for low prices has led to the installation of poor-

quality products and inferior system design and execution on site (Devi et al. 2018). Existing literature,

reports from field studies that are later referred to in this report, and stakeholder interviews support this

claim. These inferior products deliver less energy than expected or have a lower overall lifespan than has

been reported in the literature—all of which are serious issues for developers and investors whose return

on investment depends on the amount of power generated from these solar systems for the expected life

of the project. Equipment that does not conform to minimum quality standards also creates safety risks for

the distribution network. Performance and safety concerns lower investor and consumer confidence in

solar products, threatening to slow market development. This is apparent in the slow growth of the

rooftop photovoltaic (RTPV)

segment in India despite being economically viable to many conventional

electricity consumers. These concerns are more prevalent with distributed solar systems where developers

and consumers have little awareness and technical competence to judge the quality of equipment and

installation, let alone the appropriateness of system design. Given the nature of these projects (small

capacity and large numbers), Indian states, discoms, and lenders have limited capacity to monitor and

enforce existing standards and guidelines for equipment and installation.

Against this backdrop, this report presents a series of best practices and priorities for use by concerned

authorities in India to improve the quality and safety of RTPV systems. Prepared under the USAID-

NREL Partnership, and in collaboration with USAID-India’s Partnership to Advance Clean Energy-

Development (PACE-D) 2.0, this report uses primary and secondary resources to help understand the

current state of solar quality and safety in India and to provide the basis for future recommendations. An

overview of issues and lessons learned about solar quality and safety issues from the United States and

other global experiences was also conducted. The report concludes with a series of potential solutions and

identify those parties that could most aptly lead change.

This report is organized into six sections:

1. Introduction—solar energy targets, key challenges of RTPV deployment, stakeholders involved,

and need for quality and safety standards

2. International Perspective—experiences from the United States and other places globally on solar

quality, safety issues, and solutions

3. Research Methodology—how information from key stakeholders was obtained and analyzed

4. Key Findings: Quality and Safety Aspects of RTPV Systems in India—key design, component,

and installation challenges, and key drivers of poor quality and safety standards

5. Prioritized Solutions and Implementation Framework—potential solutions for addressing issues

6. Next Steps

Throughout this report, we will use the term rooftop photovoltaic (RTPV) to denote small-scale PV systems

adopted primarily by residential and commercial customers and connected to the distribution system (also referred to

as distributed solar, or distributed PV in other contexts). RTPV is the term commonly used in India even though

these types of systems are not necessarily located on roof tops.

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1.1 Solar Energy Targets and Growth in India

The Government of India launched the National Solar Mission (NSM) in January 2010 with the goal of

establishing India as a global leader in solar energy deployment. Its ambitious target is to deploy 20 GW

of grid-connected solar power by 2022. The NSM aimed to reduce the cost of solar and achieve grid

parity by 2022 through:

• Developing a long-term policy

• Deploying solar on a large scale

• Conducting aggressive research and development (R&D)

• Producing critical raw materials, components, and products domestically.

In 2014, India increased the target for the NSM fivefold, from 20 GW to 100 GW of grid-connected solar

power by 2022 (Ministry of New and Renewable Energy [MNRE] 2014). The government also

segregated this target into ground-mounted and rooftop segments, specifying a 60% versus 40% split for

ground-mounted and RTPV systems, respectively (MNRE 2019).

Though the NSM included targets for both ground-mounted MW-level systems and RTPV systems, the

initial emphasis from the market was on installations of the former; hence, growth in that sector has been

larger and currently exceeds that of RTPV deployment. According to the MNRE, as of May 2020,

installed capacity of ground-mounted systems was 32.2 GW

; installed capacity of RTPV systems in

December 2019 was 5.4 GW (Bridge to India 2019). In 2015, the MNRE developed state-specific targets

based on solar resource potential (MNRE 2015). In response, certain states developed road maps outlining

a framework for achieving these targets. In addition, many State Electricity Regulatory Commissions

(SERCs) announced regulations for net metering of RTPV systems based on technical specifications and

guidance provided by the central government. Despite these efforts, RTPV deployment has been slow in

India.

1.2 Key Challenges of RTPV Deployment

Several factors have contributed to the slow adoption of RTPV in India, including:

• Cost of generation: Solar rooftop deployment is accomplished by thousands of consumers installing

these systems on their property. These systems are typically small, with higher deployment costs

(compared to ground-mounted systems), and with higher transaction costs for financing and

installation. In the current regulatory framework, RTPV is economically viable mostly for high tariff-

paying consumer categories such as commercial and industrial (C&I) (Josey et al. 2018; Jaiswal et al.

2017). Residential consumers usually pay much lower tariffs, making RTPV less attractive to them

(Patel et al. forthcoming). Higher transaction costs coupled with limited understanding of the

technology and quality of the system, further act as deterrents to residential consumers who own a

significant portion of rooftop space. In some cases, capital subsidies (central financial assistance)

available as an incentive to residential consumers have exacerbated issues due to delayed

disbursement, complex procedures, intermittent availability and long pending overdues.

• Institutional financing: Most banks either do not want to fund such small transactions or lack

familiarity with the technology to feel comfortable financing RTPV systems. These systems are often

owned by third-party developers or financed through personal savings, making it challenging to

deploy RTPV at scale.

https://mnre.gov.in/the-ministry/physical-progress

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• Utility caution and cumbersome deployment process: To date, most rooftop systems in India are

deployed by C&I consumers (Bridge to India 2019). These consumers also contribute to a high

percentage of the margins and revenues of the distribution utilities. Utilities perceive this as a

potential revenue loss and are not incentivized to develop a streamlined process (Jaiswal et al. 2017).

Utilities would benefit from additional PV technology capacity building and training, especially

regarding the safety requirements on the DC side.

• Complexity and lack of standards: The complexity of the installation process, the large number of

system components, the wide range in quality of available options, and the limitations in defining a

single national standard for these systems are barriers to the deployment of high-quality RTPV

installations. Most consumers are unable to effectively evaluate the quality of these installations to

make informed decisions.

• Quality and safety: Stakeholders have limited understanding of the quality and safety requirements

associated with RTPV and this further complicates the adoption process. Furthermore, quality and

safety considerations are particularly important to facilitate lender confidence in this investment-

intensive sector. For example, a significant portion of the overall life cycle costs come as an up-front

investment during the deployment of the systems. To recover the investment, it is critical that the

systems perform as expected. The success and sustainability of these investments, as well as the

achievement of national renewable energy targets, depend to a large extent on the performance of

these systems which, in turn, depends upon the quality of the systems, their components, the

workmanship during installation, operations and maintenance during the life of the system, and the

safety of the financed energy systems.

Over the past few years, the drastic reduction in the cost of solar coupled with a supply glut in the market

has led to a suppliers’ competition. This has forced engineering, procurement, and construction (EPC)

contractors, installers, and suppliers to cut prices to win orders—often sacrificing basic quality and safety

requirements. EPC contractors and installers may compromise on the quality of the components, the

systems, and the workmanship to keep costs low. This has created a certain amount of scepticism in the

market on the long-term performance and sustainability of the systems. To ensure the long-term health of

the sector, grow the market, and achieve India’s ambitious policy targets, there is a need for a system that

facilitates quality in these solar rooftop systems, especially for residential consumers who will make up

the bulk of the market in the future and who are most at risk.

1.3 Key Stakeholders and Their Roles in Ensuring RTPV Quality and

Safety

Ensuring quality and safety of RTPV systems falls under the domain of several central- and state-level

institutions that develop policies, regulations, rules, and guidelines for the power sector in general and for

the solar and RTPV sectors specifically. Figure 1 presents the key actors responsible for the development

of the RTPV sector in India and highlights some of the major quality and safety initiatives undertaken by

each of them.

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Figure 1. Key institutions and their roles in quality and safety in solar rooftop systems in India.

The model regulations for net metering developed by the central Forum of Regulators, and informed by

guidelines and specifications developed by the Central Electricity Authority (CEA) and the MNRE, are

the basis on which SERCs have developed their net metering guidelines. State regulations are key drivers

for RTPV deployment, with states dictating technical, quality, and compliance requirements. This

includes the technical parameters and specifications for RTPV systems and for grid integration, as well as

identifying the various limits, checks, and approval timelines. Some state regulators provide detailed

technical specifications while others refer to those specifications published by the central authorities, such

as the MNRE and CEA. Ambiguous and loosely defined technical parameters related to design,

installation, and safety aspects, and the lack of standardization have an impact on the quality and safety of

systems being installed across states. The state-level Chief Electrical Inspectorate (CEI) and the state

electricity distribution utility are responsible for the implementation of these technical and safety

guidelines and ensuring that all systems conform to the standards laid down by the SERCs, MNRE, and

CEA.

1.4 Rooftop Solar Implementation Models and their Impact on Quality

and Safety

RTPV systems in India are primarily financed and developed in one of two ways: capital investments by

consumers (owners of rooftop) or capital investments by third-party RTPV developers, also known as

Renewable Energy Service Companies (RESCOs):

• Capital expenditures (CAPEX) model—the consumer purchases an RTPV system and either

consumes electricity through net metering or sells electricity to discoms through gross metering. Most

residential RTPV systems and most small-capacity systems (less than 100 kW) are built using this

model. Normally, the smaller residential customer hires an EPC agency to manage the project from

the beginning to the end, including design, supply, and installation. These systems are susceptible to

low quality and safety hazards

because of low-level customer awareness coupled with an emphasis on

reducing capital costs.

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• RESCO or operational expenditures (OPEX) model—the RESCO invests in, operates, and maintains

the RTPV system, and the customer provides the rooftop and purchases energy generated from the

system. This model is common with C&I customers and public sector systems (for example,

government buildings) that have larger loads and rooftop area and higher system capacities (100 kW

and more). The quality and safety of such systems are better managed and maintained because the

developer is more experienced, has access to quality control and inspections, and directly benefits

from the higher revenue from better performing systems.

As of December 2019, total installed RTPV capacity in India was 5,440 MW (1,523 MW OPEX and

3,917 MW CAPEX), of which C&I customers represented 3,964 MW, public sector government

buildings represented 728 MW, and residential systems amounted to 750 MW (Bridge to India 2019).

Currently, the large C&I and public sector systems are developed under either of these models. These

consumer types and agencies have the wherewithal to develop quality systems that are safe and perform

per guidelines. However, small CAPEX-based systems and investments are likely to be the most

dominant investment model for residential consumers because RESCOs do not find it economical to

service this segment, or are prohibited from participating. Owing to improvements in technology,

economic incentives, and intermediate subsidies, it is likely that there will be an upward trend in the

deployment of RTPVs in the future. Therefore, it is critical to develop a framework and implement

solutions that address the quality and safety concerns currently prevalent with these solar PV systems.

Though limited in number, the larger solar developers in India, take measures to ensure that appropriate

quality and safety are built into the development of solar PV systems. For example, these developers

usually have a well-established team of quality-control personnel who work with component suppliers to

ensure the quality of the components. These developers also ensure that downstream work is carried out

according to their very strict quality and safety requirements.

These larger developers can implement quality measures because they have the financial resources to buy

in bulk (allowing them to dictate quality requirements to component suppliers), employ qualified

technical personnel to ensure quality of installations and components, and track quality throughout

operations to help them make future development decisions. However, most of these developers work

primarily on large grid-connected, ground-mounted systems (larger than 5 MW) and RESCO-based

distributed and solar rooftop installations. Acting as RESCOs, these developers assume performance risks

associated with their systems; this, in turn, creates an incentive to design and install high-quality systems.

In the RTPV space, these larger developers cater to either large C&I clients or participate in large RESCO

bids for institutional players (such as municipal corporations), public sector undertakings, and other

similar government establishments with high financial ratings. Small and medium establishments and the

residential sector are typically not covered by most developers under the RESCO model because of

contract security risks. These electricity consumers rely mostly on self-financed systems or on systems

developed through smaller, local RESCOs. This leads to the following issues:

• Consumers developing self-owned systems usually lack an understanding of the quality and safety

challenges associated with these systems; they tend to invest in the cheapest system available,

resulting in suboptimal performance, potential safety concerns, and impacted investment returns.

• Suboptimal performance of systems has downstream impacts on the industry and results in lower

adoption rates by other consumers because of negative word-of-mouth publicity; fewer banks are

willing to provide loans.

Price reductions and increased competition in the market will continue to make quality and safety

significant challenges for the industry. These challenges can stall the development of the distributed solar

and solar rooftop markets, especially for small and medium enterprises, and the residential sector.

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1.5 Need for Quality and Safety Standards and Implementation

Framework

Implementing quality and safety measures requires adhering to international and national standards for

component manufacturing as well as design, installation, and workmanship. It also requires a framework

that allows stakeholders to examine whether these standards have been followed, which includes a

rigorous system of testing, monitoring, and performance mapping.

Policymakers and regulators in India have developed and prescribed standards for solar PV projects—for

both large grid-connected solar projects as well as RTPV projects (Appendix B). However, most of these

are component-level standards and do not address workmanship issues. Moreover, the adoptions and

enforcement of these standards have been left to stakeholders, such as the distribution utilities, banks,

project developers, or consumers. Project developers and EPC companies tend not to enforce these

standards under price pressures, while banks and consumers often lack the knowledge to implement these

standards. This is especially true for RTPV projects because of their large numbers, high transaction

costs, lack of knowledge among consumers and banks, and the small size of individual investments.

Therefore, to ensure quality through standards, implementing a framework is critical to enforcing

standards and associated services, such as testing, inspection, and calibration.

The key challenge lies in understanding and recognizing where quality compromises occur. For example,

during the design phase, it is critical to understand the nuances of designing strings to match the

maximum output current of strings, requirements for the design of strings to match inverters, or the use of

appropriate fasteners keeping in view the wind profile of the area to name a few. Similarly, compromises

may occur when the module manufacturers’ bill of material does not conform to prescribed standards, or

if specific standards are not adhered to during the manufacturing stage. In addition to prescribing

standards, there is also a need for on the ground support through inspections and audits.

Technical issues such as the gaps in standards or monitoring systems and the penetration of inferior

quality products in the market hamper the performance of the solar system and create a poor reputation

for PV systems and the technology (Devi et al. 2018). Developing a framework that will facilitate

developers (RESCOs and EPCs) to buy the right components, as well as ensure that the components have

been tested for quality and safety, is an urgent need. A framework will also provide developers standards

to conform to, and allow consumers to see that systems are installed in a manner prescribed by standards

and best practices.

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2 An International Perspective: U.S. and Other Global

Experiences With Solar Quality and Safety Issues

India’s unique context influences how solar quality and safety issues manifest on the ground in terms of

their specific type, frequency, and prevalence. At the same time, India is not alone in facing such

challenges. Solar safety and quality issues have persisted worldwide from the technology’s early

deployment (1980s and earlier) to today. Over time, researchers have cataloged common solar quality and

safety issues and developed best practices for overcoming them—a process that is ongoing. Since its

inception, the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) has focused

on PV reliability and system performance research to improve these technologies. NREL’s PV Reliability

Group, in particular, has been involved in several efforts related to PV system quality; the group’s

experiences and lessons learned that are relevant to India are summarized below.

2.1 Site Inspections

NREL’s PV Reliability Group regularly performs PV site inspections to directly observe possible

reliability issues (or lack thereof) and help guide research. NREL also interviews system owners. The

majority of site inspections are performed on ground-mounted systems, but some are on residential

rooftop systems. Nevertheless, important commonalities have been observed. Major observed trends over

the years, and current issues with rooftop installations, are described below.

Failures in early PV systems were dominated by component failures, often in the modules and inverters.

Some examples of common failures in older PV systems include browning, cracked wires and connectors,

and compromised solder bonds. The incidents of such failures have decreased dramatically because of

improved PV component testing and standards. Programs such as the Jet Propulsion Lab block buys

between 1975 and 1985 provided guidance on which accelerated tests could reproduce observed failures.

Such tests were subsequently incorporated into component standards, such as International

Electrotechnical Commission (IEC) 61730 for module safety and IEC 61215 for module design

qualification. Qualification to international component standards has become a minimum requirement for

many large system procurements. In rare cases where modules are not designed to meet these standards,

NREL has observed a recurrence of these early problems. Based on discussions with stakeholders in India

(and outlined further in Section 4), a majority of the quality and safety issues was identified to be module

related. While standards have been developed and adopted for ensuring module quality, implementation is

lacking in India.

System downtime because of inverter failures and nuisance trips was also widespread in early systems.

Inverter issues have been slower to resolve than the majority of early module failures but are decreasing

in frequency with wider applications of revised or new inverter standards, such as IEC 62109 for safety

and 62093 for design qualification in natural environments. Benefiting from the newer inverter standards

developed and adopted, few survey respondents reported issues with inverters in India (Section 4).

Laws (codes) in the United States cover PV system safety quite thoroughly, but there are few

requirements for PV system performance: a system and components must be safe, but system energy

generation is not strictly mandated. For example, module certification to IEC 61730/UL 61730 (a safety

standard) is required via the national electric code (NEC). The NEC and building codes also govern

system wiring and grid connection, fire resistance requirements, and mechanical loads. Only within the

last year have governments started to require performance standards, such as the state of California

adding a requirement that modules meet IEC 61215/UL 61215 design qualification to receive state

incentives.

This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications.

System energy generation can be compromised by poor choices in any aspect of the system construction.

Some system owners have cited an overemphasis on physical system completion rather than quality and

energy generation, which they believe was due to developers receiving tax incentives at physical system

completion. Thus, despite substantially improving module reliability, other factors may impact system

performance severely. An example is a system where the trackers were not certified or tested for PV

usage; most became stuck within a year of initial operation.

Some owners of large systems are more focused on return on investment through long-term energy

generation. These project owners and designers have become very technically savvy in the areas of

component certification, module degradation rates, and system construction requirements. The RTPV

consumer unknowingly benefits from this technical know-how because high-quality (certified) PV

components have become widely available.

Poor system design and installation are much more common in rooftop systems than in large ground-

mounted systems. For example, NREL has seen many rooftop systems inadvertently installed with

significant shading. Systems have been installed facing north (in the northern hemisphere) with the

designer seeing only that the location is not shaded. In other cases, installers have misinterpreted claims

about microinverters to mean that the modules can perform adequately in the shade if microinverters are

used. NREL has also seen multiple cases where installers flush-mounted modules to the roof, which

decreases performance and longevity because of hot temperatures, without discussing or explaining

higher-performance configurations to the homeowner.

These quality-related observations connected to system size are relevant for the Indian context, where

business models for RTPV deployment can further amplify these issues as discussed in Section 1.4.

A key stumbling block in U.S. rooftop system quality is that the consumer usually cannot distinguish

between a high- and low-quality system. While there are some quality marks that are discernible to a

subject-area expert (e.g., IEC component certification and North American Board of Certified Energy

Practitioners training of installers), these valid indications of quality are not well known. Instead, cost-

per-watt and customer recommendations are often used to select an installer. Even some government

websites that purport to compare installers only provide cost-per-watt information. Customer

recommendations may be misleading. Such recommendations are more likely to be based on the

installer’s personality or punctuality because most consumers cannot evaluate PV system quality. NREL

inspected a system with significant shading (using a string inverter), code violations, flush-mounted

modules, no warranty, and inoperable data transfer from the inverter, where the installer was highly

recommended by the homeowner’s friend.

When a homeowner suspects a problem with the PV system operation, it may be difficult to obtain

warranty benefits. While a part (such as a prematurely failed inverter) may be covered, the homeowner

may still be required to pay for shipping and labor. NREL encountered two cases where homeowners

were able to detect module performance problems and experienced a great deal of resistance from the

manufacturers in obtaining replacement modules (although they did eventually succeed).

Installers cite some challenges unique to rooftop installations. Some believe that they are shipped lower-

quality modules than those shipped to large sites because they cannot afford random-sample module

testing like the larger users. These installers believe that they may be shipped modules with cell cracks

and other flaws that are not visible to the eye. Some installers have also cited unhelpful inspections that

can delay the project by days. It is important to remain sensitive to these issues in thinking about quality

requirements.

This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications.

2.2 Standards for Systems—IECRE

To improve system quality and provide solutions to the issues raised in the previous section, NREL

worked with teams of international experts to develop the PV portion of the IEC System for Certification

to Standards Relating to Equipment for Use in Renewable Energy Applications (IECRE) for PV system

certification

(https://www.iecre.org/about/what-it-is.htm, https://www.iecre.org/sectors/solarpvenergy/).

This effort involved identifying the characteristics and actions associated with high-quality PV systems,

coming to international consensus on these items, then updating or creating more than 30 standards,

technical specifications, and operational documents to reflect this content.

A general description of requirements for a high-quality system at each stage of its life is included in the

IECRE operational documents (ODs). The ODs reference standards for the details of various procedures.

For example, the OD describing system commissioning (OD-401) requires that components be of high

quality and that appropriate inspection of the installation occur before the system is considered to be

complete. The specifics of component testing and site inspection are not described in the ODs.

Component testing is accomplished via manufacturer certification of products to standards, such as IEC

61215 and 61730. Operational Document 401 describes which components must be certified to which

standards. For the details of system inspection at commissioning time, OD-401 references IEC 62446-1.

Where different requirements for different size systems are logical (e.g., onsite irradiance monitoring for

large systems versus use of online climate data for residential systems), the standards specify different

classes of systems. Table 1 summarizes the ODs used for different stages in PV installation, the desired

characteristics ensured by the OD, and the standards referenced to detail the procedures. ODs are

available free of charge at

https://www.iecre.org/documents/refdocs/

. The names of PV ODs begin with

OD-4. IEC standards may be purchased from the IEC website or through an institutional library

subscription.

The IECRE PV certification system, with certified inspection bodies and all necessary ODs and standards,

was first operational in 2017. Some aspects of the system were adopted quickly. In particular, module

manufacturers were eager to demonstrate their quality-management systems through certification to IEC

62941. Inspections and quality certificates were issued for some large PV systems. However, the

community has not yet begun to include IECRE system certifications regularly in procurement or

commissioning requirements.

This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications.

-Table 1. Summary of Stages Relevant to PV System Installation, Desired Characteristics at Each

Stage, and Standards that Describe How to Achieve these Characteristics

Stage in PV

System Life

(Document #)

Desired Characteristic

Standard Where the

Requirements Are

Specified in Detail

Choosing a Module

Manufacturer

(OD 405-x)

The module manufacturer has a quality-management system in

place that covers product design, purchasing, customer

relations, monitoring, and measuring.

IEC TS 62941

Note: This step evaluates the manufacturer, not a specific product.

Choosing an

Installer

(OD 410-x)

The installer keeps records of projects and trains employees.

Training, continual improvement (including evaluating energy

production via 61724).

IEC TS 63049

The installer follows best practices for array design (including

shading, mechanical loads, etc.).

IEC 62548

IEC TS 62738

The installer follows best practices for commissioning (including

system documentation for customer, testing, and inspection).

IEC 62446-1

Commissioning—

PV System is

Complete (OD 401)

Modules are designed to be safe and durable.

IEC 61730, IEC 61215

Power electronics are safe.

IEC 62109, IEC 62093

Commissioning: System documentation is provided to

customer. Testing and inspections appropriate for residential

systems are performed.

IEC 62446-1

Performance and capacity are clearly understood.

IEC 61724-2

Checking System

Performance

(OD 402)

Compare predicted and actual irradiance this year with

accuracy appropriate to residential systems.

IEC 61724-1

Compare predicted versus actual energy production this year.

IEC 61724-3

Compare predicted versus actual system downtime this year.

IEC 61724-3

Compare predicted versus actual operations and maintenance

costs this year.

2.3 Education and Developing Best Practices

NREL has worked in industry-wide collaborations to develop best-practices guides for several topics

related to photovoltaics. Most relevant to India is a best-practices guide for PV system installation (Doyle

et al. 2015), available at https://www.nrel.gov/docs/fy15osti/63234.pdf

. This guide includes best practices

for several aspects of installation, including requirements for personnel training, company experience and

solvency, shading analysis, shading packages, and system production estimates. Requirements are

organized into a short checklist in each section of the guide. Some requirements in the guide (e.g., a

collection of roof dimensions and type) may be of only minor importance to Indian stakeholders.

NREL has also produced a best practices guide regarding how to plan and deliver effective O&M Best

Practices for Operations and Maintenance of Photovoltaic and Energy Storage Systems; 3rd Edition

available at https://www.nrel.gov/docs/fy19osti/73822.pdf

Also available online are best-practices guides for commercial and industrial PV installations (Doyle et al.

2015), operations and maintenance (Doyle et al. 2015; NREL et al. 2016), solar resource assessment

(Sengupta et al. 2015), and development of renewable portfolio standards (Heeter, Speer, and Glick

2019).

NREL promoted an education program for authorities having jurisdiction. These authorities are the state

and local officials responsible for inspections and enforcing codes related to PV system installations. The

goal of the program was to maintain high system quality but minimize costs to the installer that might be

associated with jurisdictional authorities that have not previously specialized in solar, or low-value

This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications.

inspections. Authorities having jurisdiction were educated on important points and common failures and

how approvals are typically handled in high-volume solar areas. Installers reported a significant

improvement in how efficiently inspections and approvals were executed in areas where jurisdictional

authorities participated in an education program.

2.4 Industry-Wide Reports on Rooftop PV Quality

A number of papers and online reports document observations and recommendations for PV system

quality internationally (IRENA 2017) or in specific countries such as the United States and India (IRENA

2017; Chattopadhyay et al. 2017; N 2018), Australia (IRENA 2017; Arthur et al. 2017), and Kenya

(Jacobson and Kammen 2007; Mills et al. 2014; Duke, Jacobson, and Kammen 2002; Turman-Bryant et

al. 2015). These reports contain observations of quality issues (IRENA 2017; Jacobson and Kammen

2007; Mills et al. 2014; Duke, Jacobson, and Kammen 2002), recommendations to solve quality issues

(IRENA 2017; Arthur et al. 2017; Duke, Jacobson, and Kammen 2002; Jason S. Trager 2018),

instructions and checklists (Turman-Bryant et al. 2015; IBTS 2019.; Stanfield and Hughes 2018;

Interstate Renewable Energy Council (IREC) 2010; Brooks and James Dunlop 2016; Energy Market

Authority 2011; California Energy Commission 2001) for system design and construction, consumer

guides (Energy Market Authority 2011; California Energy Commission 2001; SEIA 2018; Chace and

Clay Mitchell 2018), and a study of successful quality improvement (Jacobson and Kammen 2007;

Turman-Bryant et al. 2015). The study of PV lighting quality in Kenya is particularly interesting because

strategies were effective, and considerable quality improvements were observed (Turman-Bryant et al.

2015).

2.5 Looking Forward—Important Conclusions and Possible Paths

Experience at NREL, and that described in the literature, is consistent in its recommendations regarding

best practices for improving quality and safety of RTPV systems in India and elsewhere. Table 2 shows a

brief summary of desired characteristics, observed problems, and possible solutions based on work at

NREL and in the literature.

Listed below are five key considerations for improving quality and safety of RTPV systems as identified

from the review of this broad collection of studies:

1. Most of the time, residential RTPV consumers are unable to distinguish between low- and high-

quality systems. The purchase of a PV system represents a complicated one-time occurrence for

many consumers, many of whom have no prior experience with this technology. System quality

contains many technical details, any of which can lead to a system failure or underperformance.

Even third-party information (including some consumer guides) tends to overemphasize the

importance of initial cost per watt, most likely because there is not a readily available

quantification of quality. Products change approximately every six months, so a useful guide

must be updated frequently. Even after the system is installed, consumers do not know if the

system is producing as expected because of the complexities of temperature, irradiance, inverter

functions, and data reporting. These situations make warranty claims particularly difficult.

2. Demonstrations of quality (installers or components) are only effective if the information reaches

the customer in a clear way.

3. Many inspection checklists and certification procedures are already available. Some checklists

focus on different aspects of the PV system (e.g., components, roofing and construction, safety,

and energy generation).

This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications.

4. Residential systems often lack long-term monitoring or effective operational indicators. A

homeowner should be able to easily see if their system is operating properly or if it requires

attention.

5. A successful approach to improving residential PV system quality is likely to include an

assortment of strategies. Up-to-date and accessible communication to customers is very important

because customers drive the market. Also important are installer training and certification, use of

certified components, inspections, and incentives, warranties, and financing that encourages the

purchase of high-quality systems.

This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications.

Table 2. Desired Characteristics, Observed Problems, and Possible Solutions Based on Work at

NREL and in Literature

Desired

Characteristic

Observed

Problems

Possible Solutions

High-quality

components

Early life component

failure

• IEC component certifications—minimal cost to consumer

because manufacturer performs test once per product

• Publicize components that meet requirements online to

customers

Counterfeit

components

• Import control and random testing of products at market with

consumer-accessible online publication of results

• Development of national certification labs when possible

Installers buy poor-

• Provide channels of communication between installers and

quality components

distributors or manufacturers so those up the supply chain

because they are

know about the problems and buyer preferences.

most readily

available

Competent

installation

professionals

Mistakes made

because of lack of

training or

experience

• Make relevant training programs more accessible

• Publicize system designers and installers who meet training

or certification requirements to consumers

• Require training or certification for installers to participate in

certain types of financing or incentive programs

• Require system inspections by third parties or government

agencies. A large investment is required to make sure all

inspectors are expert enough to add value and that a lack of

inspectors does not delay projects.

Highest-quality

systems are

purchased

Consumers purchase

a low-quality system

because the initial

cost was the lowest

• Educate consumers that initial cost is not the only important

metric. Life-cycle costs are also important

• Publicize from a trusted source, both online and in stores,

components and installers that demonstrate exceptional

quality—and those that have demonstrated poor quality

• Provide incentives to customers that participate in quality

programs

• Make available a good warranty that installers may use and

customers may look for online

• Make available financing options (e.g., system lease) that

provide incentives for both the customer and the installer to

consider quality.

Confident buyers

Consumers decide

not to buy a system

because they’ve

• A trusted third-party provider continuously updates

information online that allows consumers to know they are

selecting high-quality components and installers. The

information must be publicized so that consumers are aware

of the resource

heard about some

problems

• Make available a good warranty that installers may use and

customers may look for online

• Make available financing options (e.g., system lease) that

provide incentives for both the customer and the installer to

consider quality.

This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications.

3 Research Methodology

To gain a better understanding of quality and safety issues in India, this research effort was conducted in

three stages, starting with a literature review of solar quality and safety in India, followed by interviews

with various stakeholders in the sector, and an in-person workshop.

3.1 Literature Review

Few reports are available from previous studies undertaken to evaluate quality and safety aspects of solar

PV deployment in India. Those available are based on actual field visits and tests conducted on installed

and commissioned plants in various regions in India. Similar to the global experience described in Section

2, the majority of these studies are based on ground-mounted, MW-scale systems, and only parts of some

of these studies include rooftop systems. Nevertheless, important similarities can be observed, and

recommendations for MW-scale systems are applicable to RTPV systems as well. Common findings from

these reports are corroborated by stakeholder interviews conducted for this research and are presented in

Table 3. A list of reports, including those from non-Indian regions studied for this project, is also

presented in Appendix A.

The most frequently mentioned issue in these reports is the solar module, which represents the major cost

component of the system and most affects system life and performance. These solar modules are reported

to be of varying quality from different suppliers.

Table 3. Common Findings at Various Stages of PV System Installation in India

Stage of RTPV Project Common Findings

Solar module issues Early degradation, microcracks, potential induced degradation (PID),

snail trails

Safety and protections Incorrect earthing, insufficient lightning protection systems (LPSs),

underrated fuses and surge-protection devices (SPDs), disregard for

fire-handling systems

Installation methods Partial shadows on array, long runs of direct current (DC) cables,

loose connections and wear and tear of cables, corrosion in structure

parts

Commissioning Absence of independent inspection, lack of commissioning tests

Performance Lower energy generation, intermittent monitoring of systems, slow or

no follow up on corrective actions prompted by monitoring

O&M Inadequate maintenance, no schedule for preventive maintenance

Documentation Absence of proper documents with customers, planning and design

documents not shared with customers, power purchase agreements

(PPAs) or contracts unclear in many aspects.

These findings are attributed to some common probable reasons as presented in these reports and

corroborated by stakeholder interviews:

• Lack of awareness of these module problems by all stakeholders involved in PV power projects

• Absence of independent supervision, inspection, and audit framework

This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications.

• Lack of documentation and reporting framework

• Focus on initial cost of power plant rather than levelized cost of energy

• Cost pressures that result in low-quality and unsafe PV systems.

3.2 Stakeholder Interviews: Methodology

To gain a comprehensive understanding of quality and safety of rooftop PV systems in India and the

sector status in general, a series of interviews with different stakeholders was conducted, including EPC

companies, installers, developers, component manufacturers, and others. Authorities, financiers, and

consultants were also interviewed to provide insights from their experiences in the field. As the agencies

actually responsible for onsite quality and safety, the EPC companies and installers were included in

larger numbers as compared to others. This particular group of interviewees was selected by categorizing

them into large, medium, and small players because the issues, reasons, and possible solutions would

likely be different across such segments.

Next, a questionnaire was designed and used to conduct interviews with different stakeholders in person,

over the telephone, and via written responses. Questions focused on the role of the interviewee, reasons

for poor or high solar quality and safety, impacts of low-quality systems, strategies for improving quality,

and insight on specific categories (e.g., components and humanpower).

In-person interviews were conducted with 13 stakeholders and telephone interviews with three

stakeholders from June to September 2019. In November 2019, another 8 in-person interviews were

conducted. Both of these types of interviews lasted for an average of 1.5 hours each. Several other

respondents provided written responses. In keeping with the questions used in the interviews, these

stakeholders identified current issues based on their own experiences and provided suggestions for

addressing such issues and improving the quality and safety of RTPV systems.

Interview responses were compiled and summarized by categories used in the questionnaires, which

included component, manpower, commissioning, inspection, documentation, operations and maintenance,

tools, site, installation standards, and safety. Some of these categories, such as tools, humanpower, and

site did not receive substantial responses and, hence, were combined into an “other” category for this

report. A summary list of issues, along with frequency of occurrence and impact on project development

is listed in Appendix D; a complete list of issues and possible corrective actions is listed in Appendix E.

3.3 Stakeholder Workshop

The United States Agency for International Development (USAID) PACE-D 2.0

held a solar quality and

safety workshop on January 21, 2020, in New Delhi, India, to confirm issues raised by stakeholder

interviews and to get feedback on potential solutions. Participants included representatives from key

government agencies, technical institutions, quality monitoring centers, multilateral development

agencies, utilities and distribution companies, local and regional banks, solar PV vendors and developers,

EPC companies, O&M companies, and central- and state-level policymakers. The day-long workshop

included panel discussions and breakout sessions to review and discuss three potential solutions to

improve quality and safety of RTPV in India

• Module quality certification

• Electrical safety quality assurance

https://www.pace-d.com/

This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications.

• Vendor rating framework.

Inputs and findings from these discussions were used to further refine the solutions proposed in Section 5

of this report. There was support and general agreement that the development of a vendor rating

framework as a mechanism to evaluate, monitor, and rate RTPV vendors based on certain established

standards was a timely next step for India.

This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications.

4 Key Findings: Quality and Safety Aspects of RTPV

Systems in India

The stakeholders interviewed in the survey identified major and frequently observed issues related to the

quality and safety of grid connected RTPV systems in India, much of which corroborated existing

literature and the authors’ extensive field experience. Figure ES- 1 captures some of the most severe and

frequent solar quality and safety issues organized by category or stages of RTPV system life: site

analysis, system design, installation, commissioning, and operations and maintenance. While some issues

may have a relatively low impact on energy generation, their impact on safety can be high (denoted by the

colored icons).

4.1 RTPV Project Development Cycle

The development of a RTPV project can be divided into three broad stages: design, procurement and

installation (including O&M).

• Design: the design stage includes site assessment activities, system sizing and design, component

selection and procurement planning, and scheduling the installation.

• Component procurement: the component procurement process involves contracting for the

component, including putting in place performance guarantees, specifications and standards that the

components must conform to, specifying the particular tests that the components must go through

before being dispatched from the manufacturing facility, and the specific test results that the

developer or EPC contractor would like to see before finally receiving the components.

• Installation and O&M: The final installation stage involves receiving components at the site, site

preparation, storing material, installing the system, and completing the commissioning. This stage

usually lacks standards and is more dependent on the skills and training of the installers.

Figure 2 shows the three stages and the broad set of activities they encompass.

This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications.

Figure 2. Stages in the development of a RTPV project.

4.2 Key Challenges in RTPV Quality and Safety

Stakeholders raised concerns with component-related quality issues that span several stages of RTPV

system life, including the system design and installation phases. Most of the quality and safety issues

occurred either at the component procurement stage (about 50% of quality and safety issues experienced)

or the installation stage (about 35% of quality and safety issues experienced); the design stage contributed

to the balance 15% of quality and safety issues experienced. Within the different stages, some specific

areas caused a high proportion of challenges (Figure 3). For example, in the case of system design quality,

almost half of the quality challenges stemmed from the wrong array layout, followed by string inverter

mismatch and site access. In the case of component quality, the major area of concern was the modules

and the module mounting structures, followed by junction boxes; in the installation phase, the main

quality issues were related to fasteners, handling of modules, and earthing. Given the emphasis on issues

related to system design, component procurement, and installation and O&M, this report expands on

those topics in Sections 4.2.1-4.2.3. A summary list of issues, along with frequency of occurrence and

impact on project development is listed in Appendix D; a complete list of issues and possible corrective

actions is listed in Appendix E.

This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications.

Figure 3. Design, component procurement, and installation related quality challenges based on

feedback from stakeholders.

4.2.1 System Design-Related Quality Issues

The biggest challenge identified by respondents in the design phase of RTPV development is the

difference in array layout in the installed systems versus the design layout derived after conducting a

shadow analysis using software such as PV Syst or PV Sol. For some reason, installers or EPC

contractors change the array layout on the ground, resulting in loss of generation and, in some cases, hot

spots

due to shadows that fall on part of the array. Incorrect array layout is a major error during the

design phase and can result in lower performance, which can significantly impact lifetime returns. This

issue can either be corrected or can be identified in a post-installation inspection (i.e., by checking if the

array layout on the ground conforms to the array layout on the design drawings). Similarly, our analysis

found another significant design problem that arose from the designer not matching the string voltage

with the maximum power point tracking (MPPT) voltage range of the inverter. Here again this issue can

lead to a loss of the returns of the system and can be rectified by checking if the string voltage is beyond

the inverter’s MPPT voltage range.

Another key issue identified during the design phase was the site access issue, which impacts O&M and

the quality of installation. In a number of cases, the site was not easily accessible, and workers had to take

unnecessary risks to get to the site for installation, or the site was developed in such a way that although it

was aesthetically attractive, the installation experienced generation losses due to alignment issues. Simple

precautions, such as ensuring permanent and easy access to equipment, could be incorporated during the

design phase. This issue is more apparent with arrays on superstructures where module cleaning may be

more challenging, thereby affecting performance adversely. A planned stormwater run-off system

Defects characterized by local overheating of solar cells.

This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications.

integrated into the surrounding stormwater run-off system is also essential to avoid flooding, erosion of

foundations, and muddy ground which can prevent access.

In addition to these key concerns, other design-related issues involved improper cleaning methods for

modules, inadequate earthing provisions, and inadequate structural considerations for withstanding

weather conditions. These can have a significant impact on the life cycle returns of the project; however,

most of these issues can be avoided with good quality control, timely feedback, better training, and

awareness. A summary list of issues, along with frequency of occurrence and impact on project

development is listed in Appendix D; a complete list of issues and possible corrective actions is listed in

Appendix E.

4.2.2 Component-Related Quality Issues

Specifications and standards during the design stage dictate the identification and procurement of

components for the RTPV system. Based on discussions with stakeholders, it was found that almost 50%

of all quality issues resulted from procuring faulty or substandard components. A majority of the quality

and safety issues occurred with the module and the structure, followed by junction boxes.

In the case of structures, respondents agreed that full energy loss or complete system damage was

possible if a faulty structure was not rectified. Respondents felt that structure quality was difficult to map

and ensure but was critical for the long-term viability and sustainability of the systems. Some of the

specific quality issues highlighted by stakeholders for structures were:

• Material damage and defects (of both galvanized iron and aluminum structures)

• Poorly installed fasteners and mismatched component sizes

• Improper anchoring on sloped roofs

• Poor practices and incorrect equipment used in fixing modules onto a structure

• Design errors that result in an inability to withstand estimated dead load and wind pressure

• Post-construction inadequate finishing/ cleaning-up and waterproofing

• Lack of due diligence to determine base roof strength and quality

• Incomplete, ineffective, or nonexistent certifications.

While several standards have been developed and adopted for ensuring module quality, implementation is

lacking. In terms of structures, due to the varied nature of sites, standardization is a major challenge, and

this is coupled with the fact that most of the players are small and medium industries with limited design

capabilities. This makes ensuring quality of structures a challenge, especially for small RTPV projects

installed in small towns and cities. One of the most critical components in solar PV systems is the

inverter, but few survey respondents reported issues with inverters. This may be because the market is

dominated by a few large manufacturers who may view quality as critical to gaining and maintaining

market share.

Procurement of modules and certification of structures is key to addressing these component-related

issues. Module certification is an evolving topic, and several banks, developers, and EPC companies have

learned how to manage it efficiently. However, small EPC companies and developers often lack the

technical and financial strength to undertake this certification. There are existing tests that are critical for

certifying these components and for ensuring their high quality. These include acceptance testing at a lab

or at the module manufacturer’s site (through tests such as Flash, electroluminescence (EL), light induced

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degradation (LID), and visual inspection and strict monitoring of the bill of materials). Structures have

two issues:

• Certifying the manufacturing of structures—this can be done by testing and certifying their structure

designs.

• Certifying joints and fasteners—this requires a different type of certification (e.g., finite element

analysis or wind tunnel testing) that is only possible for a limited number of standard structures that

are used across multiple locations.

In addition to the structures and modules, the junction boxes were identified as a key challenge. When

junction boxes don’t meet safety criteria, the result could be a total loss of the system from accidents.

Stakeholders also identified specific issues related to the structure, modules, and junction boxes, which

occur during the development and commissioning of RTPV systems. These issues include nonuniform

galvanization of steel, lack of certifications, rusting, no due diligence on roof strength adequacy, and the

use of poor-quality module subcomponents during manufacturing. A summary list of issues, along with

frequency of occurrence and impact on project development is listed in Appendix D; a complete list of

issues and possible corrective actions is listed in Appendix E.

4.2.3 Installation- and O&M-Related Quality Issues

The installation and O&M stages accounted for numerous quality issues identified by the stakeholders

across the life cycle of an RTPV system. Most of these quality issues relate to the installation of the

systems and their subcomponents, their packaging, transport, storage, onsite handling, and monitoring. A

key challenge was the quality of fasteners used in the structure. As discussed earlier, structure designs

need to go through a thorough wind tunnel test before being adopted. However, the biggest challenge for

the Indian market is that almost all structures are unique to match the site’s requirements; therefore, it

becomes impossible to test and certify every site for each new system or project.

Two other key issues around installation quality and safety are earthing and lightning (E&L) protection

and the handling of the modules. For example, in the case of E&L protection, some of the specific quality

issues highlighted by stakeholders were:

• Use of improper cables—wrong size and wrong type of cables are used; mismatch in cable connectors

used.

• Use of improper protection devices or no protection devices—lack of fuses and use of wrong surge

protectors.

• Inadequate or improper lightning-protection systems—improper selection and installation of lightning

arrestors.

• Inadequate earthing provisions—lower-than-necessary earthing pits or rods.

Some of the specific quality issues highlighted by stakeholders for the handling of modules were:

• Material damage and defects (revealed only over the period of installation) in cells, laminates, back

sheets, and junction box components.

• Transportation mismanagement (e.g., loosely and/or poorly packed, inappropriately loading and/or

unloading of components that causes damage).

• Invalid and mismatching module certificates.

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• Poor installation of modules without referring to the manufacturer’s instruction manual.

• Ineffective cleaning methods by installers that are harmful to the modules.

Additionally, stakeholders also identified structural hardware issues and lack of inspections by qualified

personnel. A summary list of issues, along with frequency of occurrence and impact on project

development is listed in Appendix D; a complete list of issues and possible corrective actions is listed in

Appendix E.

Table 4 summarizes the key quality and safety issues experienced by most projects between the design

and implementation stages, and highlights potential solutions that can be adopted to address these specific

issues.

Table 4. Key Quality and Safety Issues, Their Impact on Project Returns, and Potential Solutions

Stage of Project

Development

Key Issue Potential Solutions

Design

Incorrect array layout

• Array layout to conform to shadow analysis drawing (check

drawing with actual layout)

String to inverter

voltage mismatch

• PV Syst/ PV Sol reports should be used to verify proper

matching of strings to MPPT range of inverter (onsite

matching; post installation check)

Absence of safe

structural and site

access

• Maintain pathway next to array for O&M

• Easy access to modules without the need of specialized

equipment

• Provision of lifeline for safety for sloping roof installations

Components

Poor design and

incorrect selection of

structural material

• Structure design certification to match wind zone of the

location

• Proper material treatment (selection of aluminum alloy or

galvanization thickness of galvanized iron)

Low quality modules

• Confirm that supplied module bill of materials matches the

tested and certified IEC 61215 bill of materials

• Acceptance testing by buyer at manufacturing facility

o Flash test

o EL test

o LID

o Visual inspection

Improper design of

junction boxes

• Integrate with inverter or test all protection devices

Installation and O&M

Incomplete E&L

protection

• Lightning arrestors effective radius should cover array

• Ensure minimum number of earthing (3 per system)

• Soil resistivity in each earth pit (< 5 ohms)

Improper handling of

modules

• Thermal imaging test (post installation to check if micro

cracks have developed in handling)

Incorrect module

fixing hardware

• Well defined hardware specifications; fasteners, clamping

and hardening requirements

In Section 5, a comprehensive, multipronged quality assurance framework is presented that aims to

address the major design, component, installation, and O&M issues identified by stakeholders, and help

improve the overall long-term quality and safety of RTPV systems in India.

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4.3 Key Drivers of Poor-Quality and Unsafe Systems

Survey respondents offered the following list of possible reasons for poor-quality and unsafe rooftop PV

systems in India, which corroborates the authors’ extensive expertise, other literature, and experience in

the field.

4.3.1 Gaps in Existing Quality Standards

The MNRE has listed various mandatory standards applicable to different components within grid-

connected RTPV systems (Appendix B). However, these standards only pertain to components; there are

no mandatory standards for workmanship, installation, and grid integration. So, while the components

may adhere to the mandatory standards, those standards alone are not sufficient to ensure high-quality and

safe RTPV systems.

4.3.2 Focus on Capital Cost Rather Than Cost per Electrical Unit

The most common cause for various issues in RTPV systems is overemphasizing the capital cost rather

than the cost of generation or cost per generated unit. In practice, stakeholders involved in any RTPV

system installation have a singular focus—that of reducing the capital cost. In doing so, they may

compromise on various quality aspects and safety features that are essential for a high-performing system.

Because of very low entry barriers into this particular segment, many new entrepreneurs and small

agencies enter this business and compete heavily with each other solely on the basis of capital cost rather

than long-term system performance and the levelized cost of energy. Unfortunately, customers also tend

to focus on low initial cost rather than studying technical features and considering life-cycle costs.

Moreover, it is common for customers to demand pricing similar to ground-mounted, megawatt-level

projects because they incorrectly interpret the limited information available, and they lack the knowledge

to differentiate between ground-mounted and rooftop PV systems.

4.3.3 Competition in Pricing and Speed of Work

Fierce competition in the market compels the system integrator and installer to use low-priced

components as well as to cut costs by either omitting completely or undersupplying required features

within the system. Because the solar module contributes to more than 50% of the system’s cost, the focus

is usually on procuring the lowest-priced solar module rather than looking at the quality aspects, such as

the bill of material, construction quality, and track record of the module manufacturer. Basic and

mandatory standards for solar modules are easily met by all manufacturers present in the market.

However, there is also a gap in checking whether such module standard certificates are applicable to the

particular module bill of materials that is being purchased, and whether this certificate is valid at the time

of procurement. System components, other than the module and inverter, are primarily procured from

local suppliers, and may be of low quality and sometimes may not even meet mandatory standards or

requirements due to a lack of awareness, knowledge and training.

Cost cutting during system installation also happens in the balance of systems components; these can be

missing from the system or the quality may be undesirable. This can have serious impacts on the safety of

personnel, on the rooftop and building, as well as on the system and the grid. The components most

commonly used to cut costs have to do with protections, such as earthing and lightning protection, as well

as disconnect switches, overcurrent protection, and surge-protection devices. Neither grid engineers nor

customers are fully able to confirm if the supplied components are essential and/or present in RTPV

systems.

4.3.4 Lack of Training for Installers—No Eligibility Criteria

In India, the RTPV sector is at a nascent stage; hence, various stakeholders lack the proper knowledge or

experience to achieve quality systems and installations. RTPV systems are quickly becoming a

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commodity product and, similar to other products purchased by customers for their private use, customers

fully depend on the expertise of the system provider, which is the only agency they are in contact with

while choosing a system and when the system is being commissioned on their rooftop. Some

entrepreneurs are new to the field, are not extensively educated about the technology, and may not

appreciate the importance of quality, resulting in higher failure rates of small-capacity systems often

executed by these entrepreneurs. Similarly, the grid engineer who inspects the installation, primarily from

the point of view of grid safety rather than system performance, may not be well equipped to advise

installers and customers on the quality of the system.

Currently, there are few mandatory eligibility criteria for installers and system integrators for

commissioning RTPV systems. Also, the states, either through the State Nodal Agency (SNA) or

discoms, do not opt for empanelment of system integrators and suppliers because they fear the extra

burden in case of a dissatisfied customer.

4.3.5 Lack of Customer Awareness

Rooftop systems can be broadly categorized into large-capacity systems for C&I customers and small-

capacity systems for residential customers. Currently, C&I consumers primarily opt for using the OPEX

model wherein the system is designed, installed, owned, and maintained by the developer or RESCO, and

the customer is happy to pay for the energy generated from the system. Such systems typically perform

better compared to residential RTPV systems because the revenue for the developers depends on energy

generation. In small-capacity residential systems, customers may not have experience or knowledge about

system performance or expected energy generation. Most customers are happy about savings achieved in

their electricity bills even when these savings are far below the potential savings that could be achieved

by their system.

4.3.6 Lack of Proper Inspection During and After Installation

Another missing activity in the overall framework of grid connected RTPV systems is the lack of

inspections by an independent agency that is experienced, professional, and capable of identifying issues

as well as recommending corrective actions. Often, it is left to the system integrator—or sometimes only

to the installer—to commission the system. Many times, the only inspection carried out on site is by the

grid engineer, who primarily inspects the grid-integration aspect of the system, not the direct-current side

that can have a larger impact on system performance. When systems are financed by a bank or third-party

investor, these agencies have some checks and balances in place if the investor is an experienced, serious

player in the RTPV sector; currently, such investors are few in number. Bankers may depend on the

lenders’ engineers whom they would appoint only for systems above a certain capacity. Many small-

capacity systems may be inspected only by the bank officer who is generally unaware of the technical

aspects because this sector is completely new for financing professionals.

4.3.7 Absence of Mandatory Requirements for Supervision and Audit

Systems installed under a RESCO model (primarily C&I customers), may get an inhouse inspection as

well as commissioning tests conducted by an experienced engineer. There are no standards for these tests

to be conducted before declaring the system commissioned and before synchronizing the system with the

grid—either by the company engineer or by a utility-grid engineer.

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5 Prioritized Solutions and Implementation

Framework for Quality and Safety Issues in RTPV

Possible government-led efforts to improve RTPV quality and safety can be as simple as providing good

quality metrics to consumers, or as complex as detailed mandatory inspections, required by law, on each

system. To evaluate which measure to implement, one must weigh the expected impact against the

expense, resources and efforts. A progressive approach from the simplest, least-expensive solutions,

toward the more complex ones, can maximize benefits per investment, allow gradual development of

infrastructure and workforce, and provide time and experience to tailor policies before implementing the

most expensive steps. As discussed earlier in this report, in addition to adhering to prescribed standards

during the design, manufacturing, and installation of RTPV systems, there is a need for a framework that

allows stakeholders to examine whether these standards have been followed, which includes a rigorous

system of testing, monitoring, and performance mapping.

With these principles in mind, given the issues identified in this report and international best practices

reviewed, a multipronged approach to address long-term quality and safety through the implementation of

a Quality Assurance Framework (QAF) is suggested. The QAF aims to:

• Ensure market focus on developing quality systems and not solely on low upfront cost systems

• Enhance and improve customer understanding of the need for quality and safety in RTPV

• Facilitate the design, development, and deployment of standardized systems and products in the

Indian RTPV market

• Facilitate the development and adoption of industry-wide best practices for the design, procurement,

installation, and maintenance of RTPV systems

• Provide resources (information, tools) to help system owners and asset managers plan an effective

O&M program, estimate a budget for on-going O&M requirements, and effectively monitor

performance and take action based on monitoring results.

The QAF focuses on three main components (Figure 4):

• Module Quality Assurance Program: This process would focus on the components and help ensure

module quality. It would also help small-capacity and dispersed systems to adhere to certain

standards. It could be implemented by a Module Quality Certification Agency (to be established).

• Electrical Safety Quality Assurance Program: This process would certify for safety during the

design phase by ensuring adequate site access, provide design certification during the component

stage, and help ensure adequate electrical and lightning protection during the installation phase.

Distribution utilities and Electrical Inspectors could play a role in ensuring that all safety standards

for the RTPV system were followed.

• Vendor Rating Framework: Implementing a VRF may help evaluate the quality of work undertaken

by EPC companies and installers. The ratings from this framework would allow the consumer,

investor, or developer to identify the best providers and their capacity to install quality RTPV

systems. This would require establishing a Vendor Rating Agency (VRA) to oversee the

implementation of this process.

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Figure 4. Key quality and safety issues, and potential solutions.

Each component is described in the following sections, with particular emphasis on the VRF because

stakeholders identified this concept as useful and easier to implement in the short term. At this initial

stage, it is proposed that separate agencies manage each of these components until a VRF has been

established and attained scale. Once established, and as the market matures, all three components could be

implemented by a single agency—the VRA—which could act as a central authority addressing quality-

related issues in the long term.

There are unique opportunities and constraints related to the design and implementation of the three

components discussed below (Figure 5).

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Figure 5. Opportunities and constraints for recommended solutions

to quality and safety issues in India’s RTPV systems.

5.1.1 Module Quality Assurance

Modules, which still make up almost half of the total cost of the project in India, need to meet basic

quality standards for each project. Although several global standards and design qualification tests (e.g.,

IEC 61215, IEC 61730, and IEC 62804) have been developed to ensure the safe operation, service life,

reliability, and durability of PV modules, these standards alone have not been adequate in ensuring that

modules conform to these standards in India. Most manufacturers get a few of their modules tested for

these design standard certifications. However, modules being produced on each run do not necessarily

conform to the same requirements as outlined in the tests. The only way to ensure that the modules

conform to these requirements is through a set of tests on a random sample of the modules produced as a

part of the production run, making it important to address module quality issues at the manufacturing

facility or as close to it as possible.

While subjecting each production run to these rigorous module quality tests makes sense from a quality

perspective, this type of testing is not available for small developers and EPC companies that purchase

modules in small quantities from module producers. Large buyers often have their own staff or engage a

third-party quality assurance company at production centers to ensure quality because of their purchase

volume. However, the transaction costs are too high for small RTPV developers, and most module

manufacturers will not allow these developers to run these tests.

Module quality issues could be addressed through:

• Third-party testing and aggregated procurement in the short term: Aggregating and

procuring modules through larger distributors will help support testing module quality at the

production site at a lower cost. This would involve EPC companies and developers, especially

small vendors procuring modules through a single entity. This would result in better purchasing

power and economies of scale at the module manufacturer’s end as well as result in lower

transaction costs for testing.

The first step is to develop a strategy for aggregating module procurement. Costs of

implementing module quality testing (MQT) will remain relatively high unless the modules to be

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tested are aggregated. This step will include developing a demand aggregation strategy to pool

demand from solar PV rooftop module developers and EPC companies. It will also include

identifying the mechanisms by which this will be undertaken, including how costs and results can

be shared. A second step is creating a module procurement aggregator. This step includes

identifying an agency to coordinate aggregation of orders from the RTPV industry in India.

Aggregation at an agency level will lead to a number of downstream benefits:

o Economies of scale for procuring modules

o Bargaining power with module manufacturers

o Improved quality control

o Lower cost of module quality testing.

• Mandating module quality testing by the distribution utility over the medium term: Module

quality testing can also be mandated by discoms and can be implemented using a third-party testing

and validation agency. This agency would provide certification for specific lots of modules produced

that would be checked by the discom at the time of commissioning. However, costs of testing will

remain high unless conducted in large batches. Discoms would be a suitable agency to implement this

at the initial stage because they are the only government agency that visits each solar rooftop project

site. This would allow testing and certification of modules before project development.

Developing a module quality testing and certification protocol is a key step in this process. MQT is a

standard process for most large developers who either have trained technical staff or hire the services

of laboratories, such as Underwriters Laboratories (UL) and TÜV Rheinland (TÜV), to undertake

MQT. Designing an MQT protocol would include putting a standardized process with requirements in

place. It will outline the testing parameters that will be evaluated, the sampling methodology that will

be used, and the manner in which the results will be provided and interpreted. The MQT will provide

guidance to developers, EPC companies, and consumers on component quality used in manufacturing

the modules, the quality acceptance tests performed on these modules, and the results of these tests,

including details of how these tests were performed.

• Rating of module quality as a part of the VRF over the long term: Rating by an independent

agency as part of the VRF would also allow developers, banks, and consumers to understand the

quality of the modules from various module manufacturers. This would be done after commissioning

and would be time-consuming because a huge amount of data would have to be collected, analyzed,

and released. Implementing module quality certification might work more effectively once the market

matures

Figure 6 shows how this framework can be implemented.

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Figure 6. Implementation Framework for Module Quality Assurance

5.1.2 Safety Quality Assurance

Protection and safety are major concerns for utilities and, although time consuming, RTPV protection and

safety issues should be addressed by the distribution utility during the commissioning process. Currently,

safety checks are largely ignored, and some safety features are not mandated. This is exacerbated by a

lack of consumer awareness. Small RTPV projects are often not a priority for discom engineers in India,

especially when site inspection and report generation are time consuming, and most engineers do not have

access to tools and adequate training. Some state regulations mandate safety features that discoms must

uphold (e.g., the Bangalore Electricity Supply Company (BESCOM) has interconnection process

mandates and audit safety features, and Kerala CEI has published standardized single-line diagrams that

include safety device specifications), but there is room for improvement.

Based on the major safety issues discussed in this report, utilities are the best stakeholders to ensure that

junction boxes and electrical and lightning protections meet the required standards, that site access is

adequate, and to provide design certification of structures. Figure 7 shows how this process can be

facilitated.

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Figure 7. Recommended safety quality assurance process.

Note:the utility plays a major role in safety checks.

Utility personnel are often overburdened; it is important to provide the necessary tools and training to

support this process and make it more efficient. There is a need for IT-based tools and applications that

can be used to certify these requirements and generate reports, allowing utility personnel the speed and

flexibility to capture all of these requirements online. This process would also ensure improved

compliance with quality and safety standards prescribed in the regulations.

5.1.3 Vendor Rating Framework

There are currently no mechanisms in place to monitor, evaluate, and rate RTPV vendors in India. A VRF

can help measure the quality of systems as well as ensure compliance of these systems to certain

established standards. Vendor rating is a procedure whereby a VRA provides solar EPC companies and

installers a score or ranking based on factors such as the quality of onsite work (design, components,

installation) and the performance of their systems. A VRF can be used as a single point of reference for

all stakeholders, including consumers, financial institutions, and developers, to identify top-quality

vendors for future solar system installations, operations, and maintenance. As vendors (including EPC

companies or installers) and suppliers are held responsible for component and installation quality using

this framework, a VRF can provide an effective mechanism to link quality systems to market share by

putting in place a procedure to evaluate, rate, and certify vendors based on their track records of

designing, developing, and deploying systems. As such, an effective VRF may accelerate the adoption

rate of RTPV by providing confidence to customers and discoms that reputed vendors sell high-quality

solar products.

An effective VRF would identify all relevant criteria for assessing vendors. It would also provide vendors

with information about their performance weaknesses so they can take corrective action. A VRF could

provide continuous review of standards for vendors, thus supporting continuous improvement of vendor

performance. The main types of vendor requirements would include:

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• Standard quality assurance (QA) plans of vendors: consumers and the VRA should check the QA

plan of vendors, which should include incoming material quality checks, in-process checks,

quantitative methods of random testing, final system testing, and acceptable or passing levels.

• Component procurement guidelines: these would be a major component of the QA plan.

Guidelines will confirm that materials and components used in the system comply with all

certifications and confirm that these have gone through thorough and rigorous checks before

deploying into the system.

• Installation and commissioning checklists for inspection and sign off: the vendor must conduct

independent pre- and post-commissioning inspection checks, which would occur at varying levels of

detail and technicalities. These checks and their results should be available to the consumers and the

rating agency.

• Design approach guidelines: VRA should review the entire process of survey and design adopted by

the vendor, the tools used by the vendor (for shadow-analysis, structure analysis, generation

estimation, etc.), the vendor's approach for developing designs (e.g. string sizing, allowable shadow

loss, etc.), and qualifications of vendor staff to conduct these jobs.

5.1.3.1 Benefits of a VRF by Stakeholder

A VRF will provide benefits for each of the stakeholder groups involved with solar PV in India:

• Vendor Rating Agency: To develop a comprehensive framework for ranking vendors and designing

a business model to make this financially viable, a specialized agency with extensive experience in

undertaking ratings across India must be identified. The VRA needs excellent working relationships

with industry and experience in training and building capacity. The VRA would develop requirements

for rating vendors on appropriate criteria in collaboration with the MNRE and discoms. Technical and

research-focused organizations, such as the Confederation of Indian Industry, the Energy and

Resources Institute, or Gujarat Energy Research and Management Institute (GERMI), could serve as

the VRA.

• Vendors: For vendors that volunteer to participate, the VRF will assess their performance and

identify their strengths and weaknesses, enabling them to make improvements. Vendors can also use

this tool to benchmark quality.

• Developers: The VRF will help developers evaluate the performance of vendors, EPC companies,

and installers, and identify high-quality vendors. It will provide a platform to access the performance

of a specific vendor’s solar PV system in real-world conditions. The quality of construction may vary

significantly from one EPC company to another. Hence, the reputation, track record, industry

expertise, and bankability of the EPC contractor are critical when assessing the quality of a project.

With this framework in place, developers can distinguish the best from the rest. Selection of top-

ranked vendors will also provide better performance and workmanship guarantees. Developers

operate within an environment of extreme pricing pressure brought on by a competitive-bid process.

A VRF will provide developers the ability to make decisions based on quality, price, and vendor

reputation.

• Customers: The VRF will ultimately enhance the quality of systems installed by customers. It will

also promote awareness among customers about the risks of poor-quality solar installations,

operations, and deployment, highlight those vendors that have been rated as providing higher-quality

services and systems, and weed out low-quality vendors.

• Investors/Financiers: The VRF will help investors by providing preliminary assurance of the quality

and capabilities of vendors whose systems are to be financed. This will provide financiers with the

support needed to identify high-quality vendors and systems without expending much effort. Once the

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rating system is mature, financiers may also devise a system where highly rated vendors receive some

benefit in loan processing or interest rates.

5.1.3.2 Proposed VRF Operational Approach

This section outlines a potential approach to operating a VRF. Initially, the vendor rating mechanism

would be voluntary for vendors—some vendors would see the benefit of ratings through increased sales.

An eventual aim of a VRF is to make certification required for every RTPV vendor (EPC company or

installer) using an NABCEP-like framework, in order to compete in the market.

The VRF would look at a vendor’s systems and processes as well as sample installations to arrive at a

rating. The rating would be time bound and restructured as requirements change. Sampling of systems

will allow vendors to take action if issues arise and continuously improve ratings. The VRA would use

the framework to establish an internal process and standardized terms and conditions for vendor

assessment, adaptable for use by all Indian states. The VRF would also include guidelines for vendor

empanelment, tendering, O&M, and after-sales support by vendors. It will create a stringent compliance

and monitoring framework to evaluate the services provided by vendors on a regular basis and determine

penalties, such as lowering a vendor’s rating. Key parameters for rating vendors and evaluating their

performance would fall into three categories

• Financial strength—vendor’s sales trends and basic financial ratios as an indicator of growth and

acceptance in the market by customers

• Technical capacity—assessed through documentation such as standard purchase/work orders,

customer handover documents, design and engineering documents.

• Systems and processes—implementation of quality and safety would be reviewed through technical

inspections of randomly selected actual system installations covering design, component, installation

and O&M aspects. System performance and customer feedback would also be considered. Of the

three categories listed here, reviewing a vendor’s systems and processes would carry the highest

weight.

Appendix C provides a schematic of key parameters on which vendors may be rated.

The process of developing, finalizing, and deploying a VRF will involve this sequence of activities

(Figure 8):

1. Develop a rating methodology and key parameters for rating vendors: Define the parameters

based on which the vendors would be rated. These would focus on the technical and financial

strength of the vendors, their systems and processes to manage and maintain quality, the quality

of their manpower, and the quality of the installations developed by these vendors. A sample

between 5% and 20% of all systems developed by a vendor would be surveyed based on the

criteria and quality to be mapped and rated.

2. Create an IT application to facilitate the vendor rating: The rating methodology and the

parameters will be combined with an IT application that will provide a score once the rating has

been undertaken.

3. Identify a Vendor Rating Agency: Identify the agency that will manage the VRF once it is

developed. This would include piloting the process and rolling it out. This step would also

include developing a business plan and capacity development plan for the agency as well as

understanding the scope of services the agency can provide.

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4. Train rating agency/rating professionals: Define the learning and training objectives for

undertaking a vendor rating and create a training and certification program for the professionals

who would rate these vendors.

5. Market the VRF: Define the usability of the VRF, including key benefits the VRF will provide

to stakeholders. Be sure to include how the VRF will help raise customer awareness levels about

the need for high-quality and safe solar PV systems in India.

Figure 8. Process for developing and implementing a vendor rating framework

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6 Next Steps

A multipronged quality assurance framework is outlined in this report that includes:

1. Module quality assurance through a Module Testing and Certification Agency

Electrical safety assurance through utility inspections

Quality of system design and implementation through a Vendor Rating Framework.

A detailed path forward for implementing a VRF is presented. Future work is needed to develop a plan

for implementing other components of a quality assurance framework that include key institutions and

their responsibilities, timelines, and other necessary resources. Ensuring electrical safety will depend

heavily on utilities (discoms) that will have to confirm mandatory safety parameters for each system

through inspections and sanctioning procedures. An app or similar online tool could help build discom

engineer capacity to accomplish these tasks. Module quality assurance through testing and certification

would require identification of inspection and certification bodies that would work in tandem with module

aggregators, whereby costs of such a certification would be bearable even for small EPC companies and

installers.

This prioritized approach is based on the input from Indian stakeholders as well as reports of earlier

studies conducted on some sample site inspections. Given the increased involvement of different

stakeholders suggested in this report, agencies may have to adapt to evolving roles and responsibilities in

the Indian rooftop and distributed PV sector. In addition to the enhanced engagement with these

stakeholders through deliberations and interactions, it will be useful if the USAID PACE-D 2.0 program

familiarizes these stakeholders to the similar roles being played by agencies in other regions of the world.

There may be numerous things to learn from experience elsewhere and this will contribute substantially to

these agencies adopting roles in ensuring high-quality and safer PV systems in India.

This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications.

References

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Appendix A – Referenced Published Reports

Studies in India on commissioned PV plants

• Pilot Study on Quality Aspects of PV Plants in India – Strengthening quality infrastructure for solar

industry - India

• By PI Berlin, September 2017

• All India Survey of Photovoltaic Module Reliability: 2016

• NCPRE, IIT Bombay & NISE

• UL Engineering challenge 2015 – Team 1

• UL Engineering challenge 2015 – Team 2

Similar Studies in Non-Indian Regions

• 2018 Solar Industry Business and Technology Trends

• Solar Under Storm by Rocky Mountain Institute, October 2017

• Review of Failures of Photovoltaic ModulesBy Photovoltaic Power Systems Program, International

Energy Agency 2014

Best Practices and Developers’ Guides

• Best Practices Manual and Guide by USAID PACE-D TA and GERMI funded by MNRE

• Interconnection and Inspection of Grid Connected Rooftop Photovoltaic Systems – A Guide for

Utility Grid Engineers by USAID PACE-D TA and SCGJ

• Greening the Roofs – A Guide for Solar Entrepreneurs by USAID PACE-D TA and SCGJ

• Evaluation of Solar Proposals – A Guide for Financial Institutions, Solar Developers and EPCs by

USAID PACE-D TA and SCGJ

• Utility scale solar photovoltaic plants – a project developer’s guide by IFC 2015

• SAPC Best Practices in PV System Installation by NREL, 2015

• Guidelines for GRPV – UL

Quality Component Report

• Module reliability scorecard by DNV GL 2018

This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications.

Appendix B – MNRE Published List of Standards

Quality Certification, Standards, and Testing for Grid-Connected Rooftop Solar PV

Systems / Power Plants

Quality certification and standards for grid-connected rooftop solar PV systems are essential for the

successful implementation of this technology. It is also imperative to put in place an efficient and rigorous

monitoring mechanism, adherence to these standards. Hence, all components of grid-connected rooftop

solar PV system/ plant must conform to the relevant standards and certifications given below:

Table B1. Published List of Standards

Solar Module

IEC 61215/ IS

14286

Design Qualification and Type Approval for Crystalline Silicon

Terrestrial

Photovoltaic (PV) Modules

IEC 61701

Salt Mist Corrosion Testing of Photovoltaic (PV) Modules

IEC 61853

- Part 1/ IS

16170: Part 1

Photovoltaic (PV) module performance testing and energy

rating: irradiance and

temperature

performance measurements, and power rating

IEC 62716

Photovoltaic (PV) Modules

– Ammonia (NH3) Corrosion Testing

(As per the site condition like dairies, toilets)

IEC 61730

-1,2

Photovoltaic (PV) Module Safety Qualification

– Part 1: Requirements for

Construction, Part 2: Requirements for

Testing

IEC 62804

Photovoltaic (PV) modules

- Test methods for the detection of potential-induced

degradation. IEC TS 62804

-1: Part 1: Crystalline silicon

(Mandatory for applications where the

system voltage is >600 VDC and advisory for

installations where the system

voltage is < 600 VDC)

IEC 62759

-1

Photovoltaic (PV) modules

– Transportation testing, Part 1: transportation and

shipping of module package units

Solar PV Inverters

IEC

62109-1, IEC 62109-2

Safety of power converters for use in photovoltaic power

systems –

Part 1: General requirements, and Safety of power converters for use in photovoltaic

power systems

Part 2: Particular requirements for inverters. Safety

compliance (Protection degree

IP 65 for outdoor mounting, IP

54 for indoor mounting)

IEC/IS 61683

(as

applicable)

Photovoltaic Systems

– Power conditioners: Procedure for Measuring Efficiency

(10%, 25%, 50%, 75% & 90

-100% Loading Conditions)

BS EN 50530

(as

applicable)

Overall efficiency of grid

-connected photovoltaic inverters: this European Standard

provides a procedure for the

measurement of the accuracy of the maximum power

point

tracking (MPPT) of inverters, which are used in grid-connected photovoltaic

systems. In that case the inverter

energizes a low voltage grid of stable AC voltage

and

constant frequency. Both the static and dynamic MPPT efficiency is considered.

IEC 62116/ UL

1741/ IEEE

1547

(as applicable)

Utility

-interconnected Photovoltaic Inverters - Test Procedure

of Islanding Prevention

Measures

IEC 60255

-27

Measuring relays and protection equipment

– Part 27: Product safety requirements

This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications.

IEC 60068

-2 (1, 2, 14, 27,

30 & 64)

Environmental Testing of

PV System – Power Conditioners and Inverters

a) IEC 60068

-2-1: Environmental testing - Part 2-1: Tests - Test A: Cold

b) IEC 60068

-2-2: Environmental testing - Part 2-2: Tests - Test B: Dry heat

c) IEC 60068

-2-14: Environmental testing - Part 2-14: Tests - Test N: Change of

temperature

d) IEC 60068

-2-27: Environmental testing - Part 2-27: Tests -

Test Ea and guidance:

Shock

e) IEC 60068

-2-30: Environmental testing - Part 2-30: Tests - Test Db: Damp heat,

cyclic (12 h + 12 h cycle)

f) IEC 60068

-2-64: Environmental testing - Part 2-64: Tests - Test Fh: Vibration,

broadband random and guidance

IEC 61000

– 2,3,5 (as

applicable)

Electromagnetic Interference (EMI) and Electromagnetic Compatibility (EMC) testing

of PV Inverters

Fuses

IS/IEC 60947 (Part

1, 2 &

3), EN

50521

General safety requirements for connectors, switches, circuit

breakers (AC/DC):

a) Low

-voltage Switchgear and Control-gear, Part 1: General rules

b) Low

-Voltage Switchgear and Control-gear, Part 2: Circuit Breakers

c) Low

-voltage switchgear and Control-gear, Part 3: Switches, disconnectors,

switch

-disconnectors and fuse-combination units

d) EN 50521: Connectors for photovoltaic systems

– Safety requirements and tests

IEC 60269

-6

Low

-voltage fuses - Part 6: Supplementary requirements for fuse-links for the

protection of solar photovoltaic energy

systems

Surge Arrestors

IEC 62305

-4

Lightening Protection Standard

IEC 60364

-5-53/IS 15086-5

(SPD)

Electrical installations of buildings

- Part 5-53: Selection and erection of electrical

equipment

- Isolation, switching and control

IEC 61643

- 11:2011

Low

-voltage surge protective devices - Part 11: Surge protective devices connected

to low

-voltage power systems - Requirements and test methods

Cables

IEC

60227/IS 694, IEC

60502/IS 1554

(Part 1 & 2)/

IEC69947

General test and measuring method for PVC (Polyvinyl

chloride) insulated cables

(for working voltages up to and

including 1100 V, and UV resistant for outdoor

installation)

BS EN 50618

Electric cables

for photovoltaic systems (BT(DE/NOT)258), mainly for DC Cables

Earthing /Lightning

IEC 62561 Series

(Chemical

earthing)

IEC 62561

-1: Lightning protection system components (LPSC) - Part 1:

Requirements for connection components

IEC 62561

-2: Lightning protection system components (LPSC) - Part 2:

Requirements for conductors and earth electrodes

IEC 62561

-7: Lightning protection system components (LPSC) - Part 7:

Requirements for earthing enhancing compounds

Junction Boxes

IEC 60529

Junction boxes and solar panel terminal boxes shall be of the

thermo-plastic type

with IP 65 protection for outdoor use, and

IP 54 protection for indoor use

Energy Meter

This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications.

IS 16444 or as

specified by

the

DISCOMs

A.C. Static direct connected

watt-hour Smart Meter Class 1 and 2 — Specification

(with Import & Export/Net energy

measurements)

Solar PV Roof Mounting Structure

IS 2062/IS 4759

Material for the structure mounting

Note: Equivalent standards may be used for different system components of the plants. In case of

clarification the following person/agencies may be contacted.

• Ministry of New and Renewable Energy (Govt. of India)

• National Institute of Solar Energy

• The Energy & Resources Institute

• TÜV Rhineland

• UL (Underwriters Laboratory)

This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications.

Appendix C – Schematic of Key Parameters for Vendor Rating Framework

Technical

Capability

Parameters 30%

Assets

Work

experience of at

least 3 years.

Experience in

designing

systems

Number of

technical

workforce

Number of

certified

Certifications

Use of system

software

Number of

Qualified

Engineers

Experience in

providing supply

integration and

installation,

O&M and other

services for

atleast three

years.

At least one

project out of

the aggregate 1

MW should

have a capacity

equal to or

greater than

100 kW.

System and

Process

Parameters 50%

Procurement policy of the firm 2%

Quality checks as per standards and norms

Installation checks as per standards and norms

Consumer feedback

modules

Quality / certifications and gaurantee for

inverters

Commissioning

Overvoltage protection

Lightning protection 2%

Manufacturer guarantees

Minimal shadowing effect 2%

Roof perforations in accordance with technical

rules and standards

PV system / surge protection / protection

against electrical shock

The wiring system was chosen and installed that

it will withstand the expected external forces

such as wind, ice, temperature and sun

radiation

All electric circuits, protective devices, switches

and connection terminals are labeled

A schematic circuit diagram displayed on site

A general overview displayed for emergency

workers

All symbols and labels are suitably and

permanently fastened

PV modules are, in accordance with

manufacturer’s guidelines, properly fastened

and stable, and rooftop connection

components are weather-resistant

Daily monitoring of the inverter - check

operation display

Yield contract guarantee insurance

Cleaning of the modules twice a year during the

contract period

This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications.

Appendix D – Summary List of Issues Analyzed by

RTPV Project Development Stage

Table D1. Design, Component and Installation Related Quality and Safety Issues

Design Related Quality and Safety Issues Frequency Impact

Respondent

(%)

Part or full shadow on the array throughout the year or some days of the

year

H H 60

Inclined array on super structure or on sloping roofs looks good but is

difficult to clean and maintain and repair

H M 75

Wrong enclosures of JB / SCB / DCDB / ACDB

Under specifications of protection devices like isolators, MCBs, MCCBs

Structure not able to withstand high wind pressure due to wrong material,

loosely fixed members and modules, wrong design; not suitable for wind

zone according to the standard

H H 90

Provision of insufficient (or lack of) working space in form of walkways,

railings, staircases, lifelines

H H 60

Inadequate earthing provision

Over estimation of energy and emphasis on capital cost

Designing array without shadow considerations

String design exceeds MPPT voltage range of

inverter H H 60

String mismatch

H H 50

Component Related Quality and Safety Issues Frequency Impact

Respondent

(%)

Mild steel used for structure

- rusting (even with anti-rust paint) H H 70

Low

-quality module mounting structures - design errors that result in an

inability to withstand estimated dead load and wind pressure

H H 90

Lack of due diligence to determine base roof strength and quality

H H 70

Incomplete, ineffective, or nonexistent certifications

Galvanizing not uniform, not of required thickness; leading to corrosion

H H 70

Low gap between ridge of the corrugated metal sheet roofing and module

back surface; increase in module temperature

H H 60

Too thin

structure components (angles, tubes, squares, C or I section)

resulting in warping and bending of structure

H M 70

Structure Certificate not submitted; Certificate is incomplete; Certificate

does not serve the purpose

H M 70

Poor quality components (cells, EVA, back sheet, JB, etc.) used in module

manufacturing

H M 90

Missing module certificates (or invalid / mismatching)

H M 70

Procurement of modules without due diligence and inspections

H H 90

Installation and O&M Related Quality and Safety Issues Frequency Impact

Respondent

(%)

Lack of inspection by qualified and experienced engineer leaves many

areas for improvement that cannot be rectified later

H H 90

This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications.

Structure components, hardware and fixing to the roof

Walkways, railings, earth pits are not checked

CEIG / Discom inspection does not completely cover PV side aspects

Handling of modules prone to accidents and unseen module damage

Modules tightened at different torques producing stress on modules and

exposing to damage under high wind conditions

H M 70

In O&M, SPDs not periodically inspected to check if these have been

sacrificed and need replacement

H M 60

This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications.

Appendix E – Complete List of Issues and Possible Corrective Actions

It is to be noted that in the field responses and observations, as EPC or installers are party to all the identified issues as well as best practices, the

parties to take corrective actions do not include these two stakeholders. However, it is understood that all these actions are to be implemented by

EPC and installers only. The party mentioned in the ‘party to take corrective action’ is over and above these two.

Table E1. Complete List of Issues and Possible Corrective Actions