Vivek Kuthanazhi

Visual Degradation in Field-Aged Crystalline Silicon PV Modules in India and Correlation With Electrical Degradation

This paper presents the analysis of visual degradation data collected during an All-India Survey of Photovoltaic Module Degradation conducted in 2013, in which 57 crystalline silicon modules were inspected in the five different climatic zones of India. Analysis of the data indicates that the highest percentage of modules suffered discoloration in the Hot and Dry climatic zone, with the Hot and Humid zone coming in second in the list. A higher percentage of modules have suffered corrosion in the Hot and Humid zone, as compared with other zones. The modules installed in the Cold climate suffered the least degradation. Both discoloration and corrosion have been seen in modules across all age groups, even in some of the modules installed less than five years ago. On the other hand, delamination and backsheet degradation have been seen only in modules more than a decade old. The visual degradation data have been correlated with the electrical performance data and reaffirm the direct relation between encapsulant discoloration and reduction in short-circuit current and output power, as well as that of series resistance with metal corrosion.

Performance degradation in field-aged crystalline silicon PV modules in different indian climatic conditions

A survey of field-aged crystalline silicon modules in various climatic conditions in India was carried out, focusing on modules, which show visible signs of degradation. Analysis of the survey data indicates that the power degradation rate is highest in the Hot & Dry climatic zone, followed by the Hot & Humid zone, while it is least in the Cold zone. The degradation in power output of crystalline silicon modules is primarily due to reduction in the short-circuit current, followed by decrease in fill factor while the decrease in open-circuit voltage is very small. Analysis of the survey data also indicates that degradation rate of multi-crystalline silicon is slightly higher than that of mono crystalline silicon.

Linking performance of PV systems in India with socio-economic aspects of installation

A survey of PV modules in the field for more than 5 years in India has been conducted The analysis revealed that module degradation rates are linked with the social and behavioral issues of the end users. The appropriateness in system installation, maintenance and hence the degradation depends on the type of ownership of the system, the financial model for the installation and the end purpose. We found that whenever there are cash flows associated with the installations in terms of savings or income generation, the maintenance activities are properly done, irrespective of the type of ownership of the system. Community owned PV installations were found to be better installed and maintained than individual systems because of the presence of institutionalized mechanisms for operation and maintenance.

Selection of photovoltaic modules for off-grid rural application based on Analytical Hierarchy Process (AHP)

Rural electrification, especially in the developing countries, is one of the major applications of solar PV based energy systems. The choice of an appropriate PV module and battery technology is very crucial for the success of a product or business model. In the context of PV for off grid rural applications, the choice of technology is not only determined by technological parameters, but also by various socio - economic parameters and other practical constraints. The use of Analytical Hierarchy Process (AHP) as a tool is an attempt to identify and include all the parameters which influence the choice of technology, directly or indirectly and to perform a pre-simulation ranking of technology alternatives. All the factors are arranged in a logical hierarchical tree according to their level of influence in the decision making. Based on the current values of quantitative attributes and the perceptions of the decision maker, pair wise comparisons of attributes and technologies are performed and the ranks of technologies are determined. For a better understanding of the relative importance of the attributes in decision making, a `sensitivity analysis can also be performed.

All India Survey of Photovoltaic Module Degradation 2014: Survey methodology and statistics

This paper presents an overview of the 2nd All India Survey of Photovoltaic Module Degradation, conducted in the months of September to December 2014. A total of 1080 modules belonging to different photovoltaic technologies were inspected from 45 different sites which are spread across the 5 different climatic zones of India. This is the first survey in India in which electroluminescence, illuminated and dark I-V measurements, insulation resistance and various other tests were carried out on PV modules installed in the field. The goal of the survey is to determine the degradation in the field-aged PV modules and find correlations between visual, electrical and physical degradation of the PV modules. The purpose of this paper is to present an overview of the survey methodology and statistics to the PV community.

Correlation of electrical and visual degradation seen in field survey in India

This paper presents an analysis of the electrical and visual degradation data gathered in the 2nd All India Survey of Photovoltaic Module Reliability, conducted in 2014, in which a total of 1148 modules were inspected in different climatic zones of India. The modules in the Hot Climates are seen to degrade faster than modules in the Non-Hot climates. Fill Factor (FF) reduction has been found to be the main cause for power reduction in young modules (less than 5 years old), while for old modules (more than 5 years), Isc reduction is the main culprit. Visual degradation in the modules has been quantified and correlated with the degradation in various electrical parameters. The degradation in Isc correlates with the discoloration and delamination of the encapsulant and the degradation in the FF correlates well with the extent of the corrosion in the metallization.

Meeting Mid-Day Peak Loads through Distributed Rooftop PV Systems: Tale of Two Cities

This paper presents a comparative study of the expected changes in load curves of two major cities in India, if their respective rooftop PV potentials are achieved. Rooftop PV potential assessments studies done for the city of Mumbai concluded that the city has around 1.72 GW potential. Based on similar studies, the city of Delhi is reported to have around 2.56 GW potential. Load pattern of the cities were obtained from the data from load dispatch centers of the respective cities and PV generation patterns were simulated using PVSyst software. It was observed that, in Indian cities, the summer load curve has two peak demand points, one at midday and one in the late evening. In winter, the peak occurs in the morning. If we can have a fairly distributed rooftop PV system in the city (so that the local fluctuations in generation due to cloud movement, etc., can be neglected) the citys peak load demand during the midday can be easily met using distributed PV systems. Similarly, the maximum ramping rates of demand before and after the integration of PV were comparable, but time shifted, thus would not pose any major threat to the stability of the grid.

Estimating Mumbai's rooftop PV potential through mobilization of IEEE student community

Generating fine grain data about the rooftop PV potential of a city can help the city planning and administration authorities to effectively draft and execute regional rooftop PV policies. A quick and `holistic rooftop potential estimation approach was developed and tried out in the city of Mumbai, India. Students from IEEE student branches of twelve engineering institutes in the city were trained as surveyors for estimating the rooftop PV potential of buildings. They were taught how to use GIS tools and simulation software to measure the rooftop area suitable for PV installation. They did site surveys to measure the roof area of selected buildings and validated their GIS based study. They also interviewed building owners to understand their perspective towards PV. Different areas within the city were assigned to different teams of students and finally the data was consolidated and used to estimate city level potential. The study concluded that there is a potential to install 1.72 GW over various buildings in the city.

Planning for integration of solar photovoltaics into the energy needs of villages through local self governments: An experience in the state of Kerala, India

Decentralization of energy planning through local self-governments has become a possibility since the development of solar photovoltaics and other small scale power generation technologies. The state of Kerala, India is well known for its success stories in decentralized administration of villages through panchayati raj1 institutions. Panchayats in Kerala have proved their efficiency in the past by handling development projects, hence the scope for implementing decentralized PV power plants in a panchayat scale in Kerala is quite high. A study was conducted at Chendamangalam gram panchayat, Kerala, India to assess the electricity demand and rooftop PV power generation potential of a typical panchayat located in the low-lands of Kerala. The changing trends in electricity consumption due to the use and spread of new appliances and 100% grid extension to the villages could be discerned. Appliances like televisions, ceiling fans, water pumps, washing machines, electric mixers, refrigerators etc has penetrated well in this area. Inverter based power back up systems and new high power equipments like induction cookers, air conditioners, water heaters etc. are increasingly being used by the domestic consumers, which indicate a possible leap in electricity demand in the near future. The study could conclude that the collective shade free rooftop area from nearly 6500 buildings in the panchayat can support nearly 11.3 MW rooftop PV installations and it is more than enough to meet the current energy demands of the panchayat. Innovative design of custom PV solutions and institutionalization of operation and maintenance, supported with clear government policies and finance options can help in transforming a panchayat into an energy surplus entity.