Authors
Brian Westgate, Daniel Arthur, Conor Hoey, Tess Laffer
Sponsor
Alternative Technology Association
Advisors
Stephen M. McCauley, William R. Michalson
Term
March – May 2017
Abstract
The goal of this project was to assist the Alternative Technology Association by providing an enhanced assessment methodology for solar photovoltaic systems, emphasizing the development of a quantifiable evaluation of reliability and performance. To realize this goal, we interviewed industry leaders, surveyed solar consumers, and researched factors affecting solar photovoltaic system quality. The project resulted in a more comprehensive assessment methodology to aid the ATA in providing consultations that examine the value of solar photovoltaic systems.
Executive Summary
This project focuses primarily on analyzing the quality of solar photovoltaic systems. Recently, Australia has become heavily reliant upon renewable energy resources such as solar and wind power. However, as the Australian solar market continues to grow rapidly, consumers are becoming more reliant on solar photovoltaic systems that have inherent failure mechanisms. For this reason, it is important to develop a quantitative methodology capable of comparing these systems and providing the public with products that will perform reliably, at a high level of efficiency for its expected life. An assessment of this nature will help to increase implementation of solar photovoltaic systems across Australia.
The Alternative Technology Association (ATA) supports widespread implementation of renewable technologies and provides advice to consumers and municipalities seeking to install them. Among these consultations, they provide assessments for municipalities participating in bulk buy programs. These bulk buy programs allow municipalities to implement renewable technologies at a more affordable cost. For these assessments, the ATA has an assessment methodology consisting of a decision-making matrix capable of comparing solar products based upon five categories: Price, Warranty, Quality, Company Experience, and Customer Service. While the matrix was helpful in pointing consumers in the right direction, some of the ranking methods used within the matrix were rudimentary, due to the absence of reliability and performance data for products currently on the market.
This project provides a new, more comprehensive assessment methodology for solar photovoltaic systems, focusing primarily on performance and reliability of products; while also providing a better understanding of factors and metrics affecting system quality for ATA consultations.
Methodology
In order to properly complete the project, the team completed the following four objectives:
- Research factors affecting solar PV quality
- Evaluate metrics indicative of solar PV quality
- Develop an understanding of consumer priorities
- Design a more comprehensive multiple-criteria decision-making matrix to compare photovoltaic component quality
To begin, the team researched factors affecting solar photovoltaic system quality and common failure modes of systems. The team conducted interviews with industry leaders including manufacturers, retailers, installers, and researchers to gain a better understanding of the operation of solar photovoltaic systems and what factors an industry leader would utilize to classify a system as “high quality”. A coding mechanism was constructed to turn qualitative interview data regarding system quality into quantifiable data backed by industry leaders. Table 1 represents the industry leaders interviewed and their combined years of experience in the solar industry.
Through the data collected in the interviews, the team determined the types of reliability data used by industry leaders to determine system quality. The team made use of various research institutions’ data, online databases, product data sheets, and independent research to draw conclusions regarding reliability and performance of solar products and metrics which best identify them. A survey was sent out to solar consumers to determine consumer priorities when purchasing a solar photovoltaic system. The survey also provided a section for solar photovoltaic system owners to provide information about their system. The survey received 868 responses from consumers across Australia. Figure 1 displays the distribution of survey responses across Australia in comparison to the population distribution.
Findings
Consumers recognize the importance of purchasing high quality solar PV systems
Based on the results of the ATA subscriber survey, 70.62% of respondents value the quality of their system over other factors such as price, warranty, customer service, and company experience. This is critical because it reinforces the value of a more comprehensive quality assessment methodology for solar PV systems. This provides both context and importance to the project detailed within this report.
Importance of various factors affecting the quality of solar photovoltaic systems
Factors such as company reputation and location, system design, and installation were determined to affect the quality of PV systems. Interviewees continually mentioned the reputation and location of a company as important factors to consider when purchasing PV systems. A company with a good reputation and local office has proven the quality of their products and is capable of providing proper after-purchase support. In addition, it is crucial to properly design the system for a given application. The various construction types of solar PV components perform differently from application to application, and failure to account for this during design can affect the long-term reliability and cost of the system. Lastly, selecting a Clean Energy Council (CEC) accredited installer is critical to the performance and reliability of the system. Improper installation can lead to microfractures, water damage, and short circuits that limit the effectiveness of the system.
The Australian energy market currently lacks standardized shipping guidelines
Microfractures are a common failure mode identified by this study that can be mitigated by proper shipping and installation. Microfractures are caused by increased stress on the module glass. This can be caused by loading the glass above its rating. The Australian market currently makes use of CEC installation guidelines, but lacks a similar system for the shipment of PV systems. This creates major uncertainty for consumers when purchasing these systems.
Importance and lack of metrics quantifying the overall quality solar photovoltaic systems
Throughout the team’s research it was identified that the solar photovoltaic industry lacks metrics indicative of system quality. Manufacturers are extremely hesitant to publish failure information regarding their products, third party test results are not always unbiased or comprehensive, and products are changing so rapidly that performing reliability tests is extremely difficult. However, use of information of this nature has the potential to provide justifiable, uniform comparisons of PV system quality. For this reason, the team developed a methodology for performing a reliability analysis capable of generating this quantifiable data.
Recommendations
We recommend that consumers only hire installers that are accredited by the Clean Energy Council.
This study identified installation as one of the most common causes for failure with solar photovoltaic systems. Therefore, to improve the reliability and performance of PV systems, it is critical that they are installed correctly. In an effort to mitigate the risk of these improper installations, we suggest consumers only make use of CEC accredited solar installers. A company that maintains CEC accreditation has been successfully installing products for an extended time period.
We recommend that consumers solicit post-installation inspections of their systems to ensure the quality of shipping and installation and perform regular maintenance on their systems.
Consumers can solicit these inspections from their CEC accredited installer or from their state government. By conducting these inspections consumers will be able to determine the quality of the installation work. Using Maximum Power Point Tracking will allow the inspector to determine the initial functionality of the system compared to its manufacturer rating. This comparison makes it possible to identify any defects in installation, and correct them before they become more serious post-warranty problems. These inspections should be performed regularly following installation to ensure optimal system functionality. We also recommend that consumers keep a log of all inspections and maintenance done on the system to make potential warranty claims simpler if issues do arise.
We recommend that the ATA work in conjunction with the Clean Energy Council to develop industry guidelines regarding the shipping of solar PV system components.
There are currently Australian regulations regarding both the manufacturing and installation of solar PV components, but there are no such regulations for shipping. Through our interviews and research it was identified that microfractures and other damages are often caused by poor shipping methods such as stacking panels or insufficient protective packaging. This is often because the shipping protocols are currently established by the manufacturers themselves. For this reason, we recommend that the ATA work with the Clean Energy Council to develop a set of guidelines for the proper transportation of solar PV components, especially solar modules.
We recommend that the ATA solicit failure rate data from solar PV manufacturers.
We recommend that the ATA request manufacturer failure data. Whether this data be from accelerated life testing or warranty claims, it will increase the amount of reliability data available to the ATA and enhance the certainty to which they can make their assessments. The team was only successful in soliciting failure rate information from one solar manufacturer. If the ATA uses their leverage to request this data it will greatly enhance their assessments. This failure data could also be included in their published buyer’s guides for personal use by their subscribers, assuming the ATA does not need to sign a Nondisclosure Agreement to acquire the data.
We recommend a project be completed analyzing the quality of off-grid system components to the ATA’s assessment methodology for these systems.
The current ATA assessment methodology is primarily focused on the evaluation of grid- connected photovoltaic systems. However, as the Australian energy market continues to change many consumers are making the switch to off-grid and hybrid systems. These systems require additional technology such as batteries and charge controllers. As these two system types become prevalent within the Australian market it will be crucial for the ATA to have the capacity to provide justifiable recommendations to its members regarding these technologies.
Deliverables
Equipped with survey results representative of Australian consumer perspectives, as well as factors and metrics to assess system quality provided by industry leaders and additional research, the team was able to create an enhanced assessment methodology for the quality of solar photovoltaic systems. While the five categories themselves remained unmodified, each category was reweighted based upon consumer priorities derived from the survey. The quality section included more quantifiable metrics of performance and reliability, allowing for a more accurate analysis of system quality. An application specific tab was also created for the purpose of reallocating weightings based upon the application of the system being assessed. With these modifications, the ATA will be able to provide more comprehensive assessments of solar photovoltaic systems and have more confidence in the data used for consultations.
Other physical deliverables include a registry of both solar modules and solar inverters relevant to the Australian market, a new tender request form for the ATA to easily gather data for their assessment matrix when providing a consultation, and a survey for their website that consumers can access to report system failures. In addition to these deliverables, the team also provided the ATA with research regarding material performance, common failures and how to mitigate them, a comparison of the main categories of solar modules and inverters available on the market today, and an analytical tool that could be used to assess system reliability based upon survey responses.
Final Report
A Comprehensive Methodology for Assessing the Quality of Solar Photovoltaic Systems