Solar Photovoltaics in Severe Weather: Cost Considerations for Storm Hardening PV Systems for Resilience

Resilience can be defined as the ability to anticipate, prepare for, and adapt to changing conditions and withstand, respond to, and recover rapidly from disruptions through adaptable and holistic planning and technical solutions (Hotchkiss 2016). Solar photovoltaic (PV) power has many advantages as a resilient power source, including the ability to provide power after a natural disaster. While solar arrays can survive severe weather events, in some case systems are compromised and left unable to provide power (Hotchkiss 2016). For PV systems to act as resilient power providers, they must remain operational. Building a system that is more likely to survive a severe storm event can come at a higher construction cost than those built to less stringent standards.

Previous efforts have identified various system measures and practices that can increase the likelihood of a PV system surviving a severe weather event (Robinson 2018; Burgess 2018; FEMA 2018). This report provides initial estimates for the up-front cost premiums for various methods of storm hardening PV systems.

This report aims to:

  1. Provide an initial estimate of the additional costs of various storm hardening measures for PV systems
  2. Disseminate information and about strengthening PV systems and to foster greater industry communication and momentum around the topic
  3. Promote a greater consideration for potential lifetime PV system maintenance costs
  4. Encourage a greater consideration of the site environmental conditions and extremeweather events a PV system is likely to encounter over its operational lifetime
  5. Help developers weigh the costs of storm hardening a PV system compared to the costsof recovering, repairing, and repowering a compromised system following an extremeweather event
  6. Provide a resource for developers installing systems in severe weather locations, siteoperators, investors, codes and standards developers, among others.
  7. Promote the installation of more resilient PV systems
  8. Form the foundations of future work to more accurately estimate the costs of installingresilient PV systems.Overall, the main steps to PV resilience are quality assurance in system design, quality control during installation, and ongoing operations and maintenance (O&M) (Lopata 2019). Systems can fail because of one, two, or all steps, or for another reason altogether—a storm of extreme force, for example. To achieve more resilient PV systems, it is paramount that PV developers and installers promote rigorous attention to quality throughout the project. This report focuses largely on specific design features that can help make PV system’s more resilient, but ensuring quality construction and installation is equally important.This report investigates 13 storm hardening measures for solar PV systems, summarized in Table 1. For more background on these measures, please reference Robinson (2018).

This document summarizes early efforts to estimate the initial costs of storm hardening measures for PV systems. It is informed by feedback that the National Renewable Energy Laboratory (NREL) received from industry experts through one-on-one interviews. This work is only as reliable as the feedback received, and NREL understands that some of the cost estimates may differ from actual costs from projects around the globe. Furthermore, system costs are constantly changing, so the values in this report represent an average snapshot of the state of the industry. We also do not account for local variation in costs. The authors welcome feedback to achieve an even more accurate representation of storm hardening costs.

This report analyzes ground-mounted and roof-mounted fixed tilt solar PV systems only. It does not include tracker systems because fixed tilt systems are typically sturdier and an installation constructed to be storm hardened should be designed to be more structurally stable. However, tracker systems currently account for the majority of large-scale PV being installed, and they are being installed in storm-prone regions. Future work will aim to investigate storm-hardening for PV tracking systems.

This report only analyzes initial costs of each of the considered measures. While it will naturally cost more to design and build a more robust system, this initial cost could lead to outyear cost savings. These lifecycle cost savings could come from reduced O&M, decreased repair costs, and shorter system downtimes, among others. While difficult to quantify, there is also a value in resilience and increasing the likelihood of a PV system providing power after a severe weather event.

An intended outcome of this report is to identify the long-term benefits of installing storm hardened PV systems. While the focus is on severe weather regions, many of the design principles could increase resilience in other regions, as well. This report may spur further research into this area, the development of products and solutions specifically tailored to severe weather sites, and to greater understanding of the value of resilient PV installations, all of which could lead to more resilient PV systems worldwide.

This report is available at no cost from the National Renewable Energy Laboratory at http://www.nrel.gov/publications.

Download the Report

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RENEWABLES 2020 – GLOBAL STATUS REPORT

RENEWABLE ENERGY POLICY NETWORK FOR THE 21st CENTURY

FOREWORD

Every year, we launch the Renewables Global Status Report (GSR) to present the latest data and facts on renewable energy policies, markets and investments. This year, however, something is different. We collectively witnessed the adoption of immediate and drastic measures in response to the COVID-19 pandemic. Ensuing lockdowns and economic consequences have disrupted everyone’s lives.

Time seems to be separated into a pre-COVID and a post-COVID period. Energy supply and demand have been dis- rupted, and carbon dioxide emissions fell. In such unprecedented times, stepping back to look at what happened in the renewable energy sector in 2019 may seem counterintuitive. But we need to do this.

It’s clear that we need to study the global picture with a long-term view to make the right decisions going forward. If we don’t, we risk getting sidetracked by a short-term perspective. As disruptive as COVID-19 has been, the crisis does not alter observable trends in the energy sector that have persisted for years. The truth remains: we need to enact a structural shift built on an efficient and renewable-based energy system if we want to decarbonise our economies.

Many of the same themes from prior years resurfaced again in GSR 2020. Year after year, we have reported success in the renewable power sector. And year after year, we have reported that renewables lag in other end-use sectors like heating, cooling and transport, and that these sectors suffer a lack of policy support. We need to report about successes as well as take a more critical look at areas where progress is weak, to enable better decision making and advance the uptake of renewables.

In the effort not only to provide accurate data but also to advance renewables in areas of weaker historic progress, GSR 2020 is different from former editions. Rather than only tracking support for renewables broadly, we decided to actively address the disconnect in progress among sectors. You will find some new figures and the start of ongoing data tracking on renewable energy policies, generation and use in different end-use sectors. We hope that this more specific look at each end-use sector (Buildings, Industry and Transport) will provide information needed to make better decisions.

At the halfway point of 2020, we find ourselves in a period of global flux. We are also in a moment of increasing conscious- ness: public support for renewables is at an all-time high, and many people are becoming more aware of the various benefits of renewable energy. Let’s seize this unique moment to create lasting policies, regulations and targets, and an environment that enables the switch to an efficient and renewable-based energy system. Globally. Now.

Some things don’t change, even after COVID-19. As with all REN21 publications, GSR 2020 is the product of a collabora- tive process built from an international community of renewable energy contributors, researchers and authors. This year’s report consolidates data from more than 350 experts to provide an up-to-date snapshot of the state of play of renewables. On behalf of the REN21 Secretariat, I would like to thank all those who contributed to the successful production of GSR 2020. Particular thanks go to the REN21 Research Direction Team of Hannah E. Murdock, Duncan Gibb and Thomas André; Special Advisors Janet L. Sawin and Adam Brown; the chapter authors; our editor Lisa Mastny; and the entire team at the REN21 Secretariat.

We sincerely hope that GSR 2020 will contribute to important changes in the near future.

Rana Adib

Executive Director, REN21

June 2020

01 GLOBAL OVERVIEW
Renewables grew rapidly in the power sector, while far

fewer advances have occurred in heating and transport.

Renewable energy had another record-breaking year in 2019i, as installed power capacity grew more than 200 gigawatts (GW) – its largest increase ever. Capacity installations and investment continued to spread to all corners of the world, and distributed renewable energy systems provided additional households in developing and emerging countries with access to electricity and clean cooking services. Also during the year, the private sector signed power purchase agreements (PPAs) for a record amount of renewable power capacity, driven mainly by ongoing cost reductions in some technologies.

Shares of renewables in electricity generation continued to rise around the world. In some countries, the share of renewables in heating, cooling and transport also grew, although these sectors continued to lag far behind due to insufficient policy support and slow developments in new technologies. This resulted in only a moderate increase in the overall share of renewables in total final energy consumption (TFEC), despite significant progress in the power sector.

As of 2018, modern renewable energy (excluding the traditional use of biomass) accounted for an estimated 11% of TFEC, only a slight increase from 9.6% in 2013. The highest share of renewable energy use (26.4%) was in electrical uses excluding heating, cooling and transport; however, these end- uses accounted for only 17% of TFEC in 2017. Energy use for

transport represented some 32% of TFEC and had a low share of renewables (3.3%), while the remaining thermal energy uses accounted for more than half of TFEC, of which 10.1% was supplied by renewables. Overall, the slow growth in the renewable energy share of TFEC indicated the complementary roles of energy efficiency and renewables in reducing the contribution of fossil fuels in meeting global energy needs.

Among the general public, support for renewable energy continued to advance alongside rising awareness of the multiple benefits of renewables, including reduction of carbon dioxide (CO2) and other greenhouse gas emissions.

Governments around the world have stepped up their climate ambitions, and by year’s end 1,480 jurisdictions – spanning 28 countries and covering 820 million citizens – had issued “climate emergency” declarations, many of which were accompanied by plans and targets to transition to more renewable-based energy systems.

At the same time, while some countries were phasing out coal, others continued to invest in new coal-fired power plants, both domestically and abroad. In addition, funding from private banks for fossil fuel projects has increased each year since the signing of the Paris Agreement in 2015, totalling USD 2.7 trillion between 2016 and 2019. Although energy-related CO2 emissions remained stable in 2019, the world is not on track to limit global warming to well below 2 degrees Celsius (°C), let alone 1.5 °C, as stipulated in the Paris Agreement.

i The Renewables 2020 Global Status Report focuses on developments in renewable energy in 2019, and therefore does not reflect the impact of the COVID-19 pandemic on global energy systems. For immediate impacts on the renewable energy sector as of mid-2020, see Sidebar 1. An overview of the full impacts of the COVID-19 crisis on the sector will be included in GSR 2021.

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Distributed Solar Quality and Safety in India

Key Challenges and Potential Solutions

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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A Renewable Energy Mini-Grid Technical Assistance Guide – Take-aways from 15 years of GIZ support in mini-grid market development

Executive Summary – Mini-grid technical assistance recommendations in a nutshell

Over the last 15 years, Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) has trialed, adjusted and refined approaches to providing technical assistance (TA) to govern- ments interested in rural electrification with mini-grids. This report uses the wealth of experience gathered by various

GIZ mini-grid programs and derives some essential lessons leading the way towards a new understanding of the role and aim of mini-grid TA.

Successful mini-grid TA overcomes the dilemma of expectations between governments and mini-grid companies. Governments typically want to see successful pilots readily deployed in their own country, plus potential financing for large-scale mini-grid roll-outs lined up before they take the effort of adjusting

the policy and regulatory framework. In contrast, private mini-grid companies want to see an enabling policy frame- work in place before they start investing. The TA provider brings the “loose ends” together through the promotion of successful mini-grid pilots, rural electrification and energy access planning, the development of mini-grid regulation in cooperation with the government, capacity building with the public sector as well as the private sector, the development

of country specific tender mechanisms, the acquisition of funding for large-scale mini-grid roll-out and the promotion of productive use of electricity and new business model development. GIZ project managers report that embedding
a mini-grid expert into the government partner’s organization 
has facilitated communication and capacity building, while various units and external experts address the many aspects
of project preparation and implementation. On the private sector’s side, hands-on support for pilot implementation (system design, financial modelling, capital acquisition, etc.) is usually more welcome than theoretical training sessions. The TA provider’s main challenge is to coordinate all relevant stakeholders including Ministries, Departments and Agencies (MDA), parliament, private sector, academia and civil society, towards finding a national consensus on the degree of gov- ernment funding channeled into mini-grids vs. mini-grid tariffs charged to electricity customers and institutionalizing imple- mentation instruments. While a complete national consensus is usually impossible to achieve, getting as close as possible to this national consensus requires comprehensive coordination

efforts, as well as the use of technically clear language in explaining state-of-the-art delivery models and regulatory concepts. Usually, the delivery model and related regulatory concept selected for implementation is also a direct deriva- tive of the discussion on the national consensus level. “The devil is in the detail”, and this is where GIZ’s long-term on-site presence, intercultural competence, institutional relations and long-term mini-grid TA experience has proved to play out especially well.

Mini-grid TA providers must understand that they have succeeded once the mini-grid market thrives without them and their service is no longer required. This can be achieved best through thorough front-to-end planning, whereby

the endgame of mini-grid TA is the hand-over of all market coordination tasks to a group of organizations managing the large-scale roll-out of mini-grids. These are usually government entities in cooperation with a development bank. In the past, this hand-over has often not worked as fluently as possible. In some cases, TA provider and development bank have found each other in competition for the same government staff resources in the implementation of projects on both ends. In other cases, development banks find frameworks have been developed in a manner unsuitable for large-scale investment, ignoring the fact that TA without the lever of large-scale financing which only development banks bring along, makes governments much less motivated to adapt and thus success is much harder to achieve.

When mini-grid TA providers are aware of development banks’ conditions to start a mini-grid roll-out program and financiers give a clear indication to the government that once these frameworks are in place, access to large-scale finance shall be available, both conflicts above can be resolved. In this manner, mini-grid TA providers have a clear aim to work towards, and development banks find perfect starting conditions once they enter the mini-grid space in a country. It is critical for the health of a renewable energy market that primary stakeholders are aligned, sending one clear message to the private sector, and for this, intense cooperation between government, TA providers and development banks is necessary.

The most fundamental condition for a mini-grid roll-out
is the financial sustainability of mini-grids. Innovations improving the financial sustainability of mini-grids are evolving with support from mini-grid TA. So-called Fourth Generation business models use mini-grids as a starting point to generate additional revenues beyond electricity sales to village customers. While larger financing windows are com- ing online in an effort to accelerate off-grid electrification, mini-grid TA is now tasked to identify and implement Fourth

Generation mini-grid business models in cooperation with mini-grid operators. In addition, new methods of electricity demand projection based on household Average Revenue Per Customer evaluations will probably soon help reduce the highest risk for profitability in mini-grids, the demand or volume risk. If TA can also overcome the mistrust between private sector and governments, leading to the private sector not embracing regulation, the basis for a successful and flourishing mini-grid sector is set.

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AN OVERVIEW OF BEHIND-THE- METER SOLAR-PLUS-STORAGE PROGRAM DESIGN: WITH CONSIDERATIONS FOR INDIA

Executive Summary

Indian consumers have been deploying behind-the-meter generation (predominantly diesel backup, and, more recently, photovoltaic) and storage systems (predominantly lead-acid and other kinds of batteries as uninterrupted power supplies) by the millions for decades (Jaiswal et al. 2017; Seetharam et al. 2013; IFC 2019). These storage systems are used by consumers to address reliability issues within the Indian power system, and their deployment is driven by consumer preference rather than any specific government program or policy. However, the same energy storage systems could provide additional services to the consumer and distribution companies if properly regulated and designed from the outset to be grid interactive. Grid-connected distributed solar PV (DPV), or rooftop solar, has also seen wide deployment in India and features prominently in the Government of India’s plans for a transition to clean, reliable, and affordable energy for all. At the same time, many utilities and state governments, as well as the central government in India are currently funding-constrained for both operational and future capital expenditures in the power sector, and some perceive customer-sited resources as exacerbating existing financial challenges.

In that context, behind-the-meter energy storage systems paired with distributed photovoltaic (DPV)— with the capability to act as both generation and load—represent a potentially unique and disruptive power sector technology capable of providing a range of important services to customers, utilities, and the broader power system in India. Globally, jurisdictions with high penetration of DPV have seen faster uptake of behind-the-meter energy storage systems, such as in California and Hawaii (GTM and Energy Storage Association 2019). India, with more than 4 GW of installed rooftop solar, is primed for the uptake of behind-the-meter energy storage, as consumer economics become more attractive with the fast- falling cost of energy storage systems. A proper framework to coordinate the deployment and operation of these distributed systems can balance stakeholder benefits from their presence on the grid. Without appropriate regulations or technical requirements, however, these systems could potentially 1) cause safety concerns for the utility; 2) exacerbate utility revenue losses; or 3) limit the ability for stakeholders to achieve certain policy goals. This report aims to offer a comprehensive, evidence-based approach to designing customer programs based on experience in the United States that can help regulators, utilities, and policymakers in India manage the range of challenges and opportunities that increased behind-the- meter energy storage deployment will bring to the power system, in particular when these systems are paired with DPV.

This report has been prepared by the National Renewable Energy Laboratory (NREL) with support from the U.S. Agency for International Development (USAID) for discussion purposes with a broad range of stakeholders. These include Indian regulatory agencies (such as the Forum of Regulators, the Central Electricity Regulatory Commission, and various State Electricity Regulatory Commissions), policy makers, utilities, and developers to inform a broader dialogue around the future direction of Indian states’ approach to regulating and facilitating DPV-plus-storage systems. Importantly, this report is intended to offer key regulatory considerations for facilitating DPV-plus-storage programs for retail customers. As the role of regulators is often to convene and balance the interests of a broad range of stakeholders, including policymakers, utilities and customers, this report focuses on their role in the development of behind-the-meter DPV-plus-storage programs. Throughout the report, relevant cases from U.S. states are provided as examples of how novel regulatory issues related to behind-the-meter energy storage systems paired with distributed photovoltaic are being addressed in practice.

Click here for the full report

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Solar Risk Assessment: 2019 – Quantitative Insights from the Industry Experts

Introduction

“In God we trust, all others must bring data.” – American Statistician W. Edwards Deming
Rarely does a single investment yield both significant social and financial benefit. In this way, solar is unique: this rapidly growing asset class offers the promise of substantial returns on investment in both.

While the financial community is—rightfully—focused on newly emergent risks of this asset class, such as managing the merchant tail and basis risk, it’s important that the financial community remains vigilant on the question of solar production risk.

Over the past few years, it’s become in vogue for financial investors and pundits alike to publicly dismiss the possibility of a solar power plant underperforming, with remarks like, “The sun will always shine,” and “Panels always work because they have no moving parts.” Success breeds complacency, and complacency breeds failure.

We are among the industry’s leading experts on the measurement and management of solar production risk, cumulatively representing hundreds of years of experience in our respective fields. Each of us are risk specialists with in-depth data on a specific element of solar production risk.

Rather than publishing “yet another” opinion, we are committed to letting the data speak for itself. Designed intentionally for a non-technical financial community, this report will be refreshed every year to provide investors with the latest insights on the evolution of solar generation risk.

Fundamentally, it is our hope that this report will serve as a guide for investors who recognize the importance of allowing data-based insights to inform the deployment of capital.

We look forward to the shared work of advancing our solar industry.

TOC

kWh Analytics: The “1-in-100 Years” Worst Case Scenario? It Occurs More than 1-in-20 Yearspage3image44576960

DNV GL: Narrowing the Performance Gap: Reconciling Predicted and Actual Energy Production

PV Evolution Labs: Over 5% of Commercial PV Modules Fail IEC Testingpage3image44574080

Borrego Solar: Thoughtful Inverter Procurement Can Prevent 25% of Lost Revenue: Inverter Warranty Management

Clean Power Research: Understanding Irradiance Value in Solar Project Bankability: How to Sniff Out Irradiance Shopperspage3image44576192

Heliolytics: Recoverable Degradation: How to avoid 0.1%/yr Losses Clean Energy Associates: Aggregate Factory Report Shows High Levels of Major (35.5%) and Critical (1.3%) Findings Among Supplierspage3image44570816

Strata Solar: Force Majeure & Energy Modeling: 1 Hurricane, 81 PV Plants Downpage3image44567168

Wood Mackenzie Power & Renewables: Solar O&M Pricing has Dropped ~60% with More to Comepage3image44571392

SunPower: Incomplete EPC Punch-listing Results in 1.2% Performance Loss in Year 1 Operations

Click here for the full report

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Data shows solar asset underperformance and bias towards optimistic pricing

Image: Black & Veatch

Solar assets are underperforming far more frequently than official energy estimates would suggest, validating an industry-wide bias towards overly optimistic pricing, according to the industry experts who contributed to KwH Analytics’ 2020 solar risk assessment report. “From a business standpoint, this means that smart investors need to take a step back and adjust to reality,” Richard Matsui, CEO and founder of kWh Analytics said.

“P90 downside events occur so often that they have nearly become P50,” kWh Analytics said in this year’s Solar Risk Assessment report. By definition, P90 events should occur once every 10 years, but they are now at least three times more frequent because of the unreliable energy estimates that have been baked into projections.

The situation is fueled, in part, by the fact that it is a seller’s market; buyers need to be competitive to get the best solar assets.

“Many projects perform up to the rosy expectations but, on average, projects are underperforming their financial expectations,” Jackson Moore, head of DNV GL’s solar section said, noting that the data-driven insights in the report make this clear. “We want data to be as accurate as possible, so it can support a sustainable solar industry,” Dana Olson, global solar segment leader at DNV GL added. Accuracy means avoiding a correction, he added, noting that the solar industry’s optimistic projections problem will not be solved without transparent insight into the sources of underperformance being experienced in the field today.

According to Matsui, the structural setup that underpins the aggressive solar production predictions bias exacerbates the situation. Like the big three credit rating agencies pre-financial crisis, the independent engineers that are hired by solar developers to give solar production estimates have an inherent profit motive for giving an aggressive projection, Matsui explained. “It’s a way to gain market share,” he said.

The data is hard to dispute, however. The report noted that for commercial scale solar projects optimistic irradiance assumptions contributed to a 5% underperformance on a weather-adjusted basis and that “weather-adjustment bias” is responsible for up to 8% bias in measured underperformance.

The report goes on to highlight O&M cost variation issues, disappointing inverter performance and the increasing frequency of diode and string anomalies after the first year.

Source: PV Mag

Click here to access the KWh 2020 report https://www.kwhanalytics.com/solar-risk-assessment

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PLEASE NOTE THAT WE ARE NOWSOLAR.WORDPRESS.COM or NOW.Solar, the old links will no longer function, please use in place of natgrp.wordpress.com

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Impact of Component Reliability on Large Scale Photovoltaic Systems’ Performance

Abstract: In this work, the impact of component reliability on large scale photovoltaic (PV) systems’ performance is demonstrated. The analysis is largely based on an extensive field-derived dataset of failure rates of operation ranging from three to five years, derived from different large-scale PV systems. Major system components, such as transformers, are also included, which are shown to have a significant impact on the overall energy lost due to failures. A Fault Tree Analysis (FTA) is used to estimate the impact on reliability and availability for two inverter configurations. A Failure Mode and Effects Analysis (FMEA) is employed to rank failures in different subsystems with regards to occurrence and severity. Estimation of energy losses (EL) is realised based on actual failure probabilities. It is found that the key contributions to reduced energy yield are the extended repair periods of the transformer and the inverter. The very small number of transformer issues (less than 1%) causes disproportionate EL due to the long lead times for a replacement device. Transformer and inverter issues account for about 2/3 of total EL in large scale PV systems (LSPVSs). An optimised monitoring strategy is proposed in order to reduce repair times for the transformer and its contribution to EL.

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Solar Under Storm Part II – Select Resilent Rooftop Best Practices

Solar Under Storm Part II is a response to the overwhelming reception of the original report, which provided best practices for ground-mount solar photovoltaic (PV) projects. It is also a response to stakeholder requests for a rooftop-focused report for the growing commercial and residential solar industry in the Caribbean and other vulnerable geographies with exposure to high-wind events.

High wind speeds increase risk factors for solar projects tremendously, but many solar installation companies inadvertently overlook or incorrectly apply low-wind speed designs (borrowed from Europe or the United States) for projects in high-wind zones like the Caribbean. These low-wind mistakes become catastrophic in high-wind events.

PREFACE

Solar PV failure reporting is needed because some failures are highly visible while others are not,
either because they are infrequent in occurrence or because they are privately dealt with and not publicly published. Showcasing a wide range of failures has multiple benefits:It provides proof to designers, installers, and customers that solar PV system resilience matters

Ramifications for product and project design, vendor selection, installation, and maintenance become real because they are tangibly connected to real- world failures

It helps solar professionals learn from past mistakes, which is critical as repeating mistakes damages the reputation and credibility of the solar industryLike the first version, this report provides an opportunity to address resilience for both a general and technical audience.

The report disseminates technical information to non-technical readers and creates a more informed solar professional, regulator, government official, utility, and customer. A well-informed customer base will systematically strengthen the PV industry by requiring vendors to incorporate resilience guidelines into their projects.

In an industry that has experienced drastic cost reductions year after year, in the “race-to-the- bottom” aspect of project and product design, it is critical for customers to understand best practices and not accept low-cost shortcuts that could jeopardize project life or energy production. Supplying the customer with a minimum set of guidelines raises the bar, and those guidelines can only be improved through innovation and definitive testing, which in turn creates a stronger industry.

The purpose of this document is to respond to the growing needs of the solar industry and combine field observations, photographic evidence, and expert analysis to provide actionable recommendations aimed at increasing the resilience of current and future rooftop PV systems. This report will touch upon flat- roof and pitched-roof PV power systems containing flat-mounted, tilt-mounted, fully ballasted, and hybrid ballasted/penetrating systems. It excludes canopy PV systems and ground-mounted systems (both fixed and tracking) as the recommendations for rooftop projects are specific to their application. Canopy and tracking systems may be addressed in future versions of the report if interest persists. Ground-mounted systems were addressed in the original Solar Under Storm report, which is still available from Rocky Mountainpage7image10047808

1

This report is organized into five sections:

1. Introduction
2. Root cause identification methodology and findings
3. Failure mode and effects analysis (FMEA) 4. Technical discussion
5. Conclusion

The intended audience for Sections 2, 3, 4, and the Appendix is engineering professionals responsible for PV system design, PV system specifications, and/ or PV system construction oversight and approval. Sections 1 and 5 are intended for a more general audience of customers, governments, utilities, regulators, developers, and PV system installers who are interested in improving PV system survivability to intense wind-loading events.

Solar Under Storm Part II was developed with direct feedback from solar companies in the Caribbean that learned lessons in solar project resilience firsthand during and after Hurricanes Irma, Maria, and Dorian. Continuous feedback from the solar installer community is vital to the success for solar PV resilience. Thus, RMI and the Clinton Foundation’s Clinton Climate Initiative will host workshops and other opportunity for on-going communication on this topic—notably through the forum of the Clinton Global Initiative (CGI) Action Network on Post-Disaster Recovery.



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