Improved Monitoring Leads to Greater Efficiency

The market for sustainable, renewable energies is growing fast and, in recent years, great progress in terms of the overall efficiency of PV systems has been made. In order to follow the constantly growing PV market it is necessary to develop more sophisticated monitoring tools which are capable of finding a fault or failure in the PV system as soon as possible. The ability to predict failures by monitoring changes in system parameters offers plant owners the possibility to increase profitability by decreasing downtime.


A recent study by the International Energy Agency found that PV plants are performing at a satisfactory level within given parameters but could achieve higher levels of output. “Task 13”, a research project set up by the Photovoltaic Power System Programme (PVPS), a cooperation platform within the IEA, set out to investigate module errors, analytical monitoring methods and long-term performance analyses. Its findings can be summarised thus (all IEA PVPS Task 13 reports can be found here):

• Faults and defects reduce PV plant efficiency
• Fault finding and troubleshooting must be carried out in greater depth
• IEA recommendation: measurements should be taken directly at the junction box

The Performance Ratio (PR) of PV plants has increased by up to 20% today when compared to 35 years ago, with some plants running at as much as 90%. Others, however, can only point to a value of 70%. Investor confidence would be greatly boosted by increasing the PR to a higher, sustained level, resulting in higher bankabilitylower capital costs and hence lower production costs. The way to achieving this is through rapid, exact fault finding. As things stand at the moment, profit-reducing faults remain, in some cases, undetected. If detected, a more exact analysis of the problem can be prohibitively complicated and expensive. It is true to say that it is less than clear as to which methods are best at finding which faults. Defective bypass-diodes are a case in point. Although they pose a danger to safety, no great effort has been made to find a reliable way with which to detect them (for further information please see IEA PVPS Task 13, Review of Failures of Photovoltaic Modules Final, 2014).

The answer to these problems is module-specific monitoring. The IEA recommends that measurements be taken directly at the junction box. It is impossible to say whether a reduction in performance is due to a system error or merely lower irradiation, when monitoring is conducted only at the power collection point. In the event of a PV plant producing less energy than expected, junction box or string based monitoring significantly reduces the amount of time and money for detecting the failure.

Monitoring at the junction box level is, therefore, strongly recommended. Junction-based monitoring could lead to an increase in revenue of up to 12%. This is in reality a potential 400% increase when compared with the hitherto predicted 3% plant revenue. So the IEA’s recommendation for junction-based monitoring would not only revolutionize O&M of the PV industry but also hugely increase profits for operators. Real-time remote diagnosis enables the taking of immediate action without wasting any time, thus avoiding revenue losses. It pays to remember that defective parts affect not only the performance of part of the plant but the plant as a whole. Precise directives based on intelligent analysis software plus an easily understandable presentation of results facilitate not only a sound decision-making process even before a team of specialists steps foot on the plant, but can also reduce costs even further as the team need not be of an exceptionally high professional grade. Upon the failure being identified the module in question can simply be exchanged resulting in low revenue loss and no extra costs due to the commissioning of a team of specialists to find the failure.

The one remaining question is whether there is already a product on the market that can achieve all this. And the resounding answer is a clear yes. The SunSniffer is capable of all this, collecting and analyzing data at junction box level, making fault finding and elimination child’s play.