In a four-year project sponsored by the German Federal Ministry of Economics and
Energy, a consortium of German experts assessed the quality of actual PV power installations.
The researchers now report on how the effects of several common module failures on module and
string performance highlight the importance of consistent quality assurance to prevent risks to
Module failure | Defective modules causing power losses in PV systems need to be easily detected with a rapid and cost-effective inspection method. Researchers from Institute for Solar Energy. Research in Hamelin (ISFH) explain how UV fluorescence of module encapsulation polymers is used for the fast detection of module failures under daylight conditions without disconnection, allowing the inspection of up to 200 modules in an hour during daytime.
Operations and maintenance | India’s solar industry has been focused on reaching a hugely ambitious target of 100GW of PV by 2022. But as Tom Kenning reports, the need to get smart on managing and maintaining solar assets is now becoming an overriding priority
Forecasting | Predicting the power production of a PV plant offers a multitude of benefits to plant owners and grid operators. Jose Ruiz-Arias looks at the challenges of accurate forecasting across different timescales and in different climate zonesForecasting | Predicting the power production of a PV plant offers a multitude of benefits to plant owners and grid operators. Jose Ruiz-Arias looks at the challenges of accurate forecasting across different timescales and in different climate zones.
Data | The collection of inaccurate data at any point in the life cycle of a solar plant will undermine almost every aspect of the investment accounting. Mark Skidmore, Samantha Doshi, Matthia Heinze and Christos Monokroussos from TÜV Rheinland discuss the importance of precision data gathering in mitigating risk for builders, operators and financiers
System monitoring | The international standard guiding the monitoring of PV systems has been revised to include greater emphasis on accuracy. Will Beuttell of EKO Instruments explains some
of the key aspects of the revised standard and how it will help satisfy the maturing PV industry’s appetite for better quality data on plant performance.
O&M | Every photon and electron lost in a PV system represents unrealised revenue. The Solar Energy Research Institute of Singapore has developed a holistic diagnosis package – the PV System Doctor – to identify and cure underperforming PV power plants in real time. The team behind the service explains how it helps maintain a healthy PV system and ensure expected returns – or even surpass them
Wireless monitoring can offer your solar business real-time data with the lowest cost of ownership, explains Aeris.
Potential induced degradation (PID) of photovoltaic (PV) modules gets a lot of attention since 2010 when Solon published their findings about a degradation mechanism in their PV modules caused by high potential differences. When multiple PV modules are connected in series, a potential difference up to 1000 V or at some places even 1500 V is created between the cell and the grounded frame. This electrical field causes a leakage current and ion diffusion. PID is a multi-level degradation with causes and solutions at cell, module and system level.
A test campaign was conducted within the frame of a feasibility study for pidbull, a curing technology for PID developed by pidbull nv. 80 PV modules were characterized whereof 49 PV modules were stressed and cured for PID. The selected set of PV modules was composed of 49 different module types of 33 brands. The test was done according to the foil-method, as described by the standard in progress IEC 62804. However, to apply higher stressing and curing rates, the modules were tested with an aluminium foil inside a climate chamber for 96 hours. After the stress test, only 22% of the tested modules passed the 5% loss criteria as described by IEC 62804. In other words, 78% out of a set of today's most installed PV modules in Flanders are PID sensitive. Remarkable is that only 16 out of the 49 PV modules have less than 20% PID after the stress test. Additionally, a linear trend for PID reversibility was shown for modules with a stress level of less than 85%. The modules which lost more than 85% due to PID showed a lower recovery rate or in worst case didn’t recover at all.
Asset management | As one of the biggest utility PV owners in the UK, Foresight has extensive experience of getting the most out of operational solar plants. Its technical director Arnoud Klaren draws on some of the lessons the company has learned from minimising the risks that affect solar projects over their lifetime.
Operations & maintenance | Proposals by Chinese authorities to scale back the subsidies available for grid-tied PV will require new efforts to maximise the performance of power plants. Karl Hong Wan of the GCL Design & Research Institute explores some of the innovations in O&M practices that will help China’s solar industry cope with decreasing financial support.
The timely and skilful interpretation of performance data from the monitoring of operational PV power plants is vital to improving the management and thus profitability of those plants over their lifetime. Achim Woyte shows how data mining and artificial intelligence can serve the management of solar assets.
The past two years have seen a boom in the deployment of mobile PV testing laboratories. Sara ver Bruggen reports on how technological advances are helping investors and developers in new and emerging solar markets get the best from their assets.
Potential-induced degradation can cause significant power loss in modules if the appropriate precautions are not taken. In the first part of a new series in PV Tech Power on module failure, Peter Hacke and Steve Johnston assess the current state-of-the-art in detecting, avoiding and mitigating the worst effects of PID.
The European solar industry has followed the lead taken by its counterparts in the US by developing best practice guidelines for the burgeoning O&M business. Stefan Degener, senior director of O&M at First Solar, who led a group to develop the guidelines, speaks to Ben Willis about their significance and aims.