ADLER Solar database: Performance levels of crystalline silicon modules versus thin film modules evaluated

2/13/18, 12:53 PM -

The data evaluation of testing over 40.000 PV modules between 2008 to 2015 shows that thin film modules were significantly more prone to reduced performance

Based on measurement readings of its in-house database of over 40,000 PV modules evaluated between 2008 to 2015, ADLER Solar has gained revealing insights in re the quality of PV modules. Tested under unified „Standard Test Conditions“ (STC), the performance level of crystalline silicon as well as thin film modules were evaluated.

Original ratings of the tested modules ranged from 39 Wp to 340 Wp. CTO Sönke Jäger, responsible for the evaluation, recorded the respective deviation from quoted original ratings. The interpretation of the ADLER Solar measurement readings showed that tested thin film modules were clearly more susceptible to lesser performance rates than crystalline silicon ones. The results also made obvious that most degradation mechanisms were module inherent, read in this tested batch the cause for capacity reduction lay primarily on cell level.

What role did micro fissures play?

Another interesting result of this study: there was no explicit linear correlation between the size of micro cracks in crystalline silicon modules and underperformance; rather, it seemed to depend on many different factors like shape and length of the fissure, cell position and intensity. Noteworthy was as well that many PV modules with various, heavy micro cracks often presented an underperformance rate below the warranty value limits defined by manufacturers.

Stopping degradation through targeted Repowering measures

“Accordingly, especially PV systems with thin film modules offer great repowering potential and thus the chance to replace affected modules with new, more efficient ones for the remaining life cycle. However, rather than a simple exchange of modules, it is all about a smart redesign of your PV plant according to latest standards: from repositioning modules to a complete revamp of the net grid feed in concept. Plus, using the freed-up space for a new PV system (up to 750 kW) to generate additional revenue according to the EEG 2017 feed in tariff stipulates a classic win-win situation,” explains Sönke Jäger, CTO ADLER Solar.

PV insider with 10 years of experience

Securing quality levels of PV plants and performance optimisation have been a core competence of ADLER Solar for 10 years by now. The PV experts will continueto examine the quality of PV modules based on age and origin. Looking at differences between various crystalline silicon modules as well as a separate assessment of new modules when it comes to incoming goods inspections is also on the list for future projects.


About ADLER Solar

ADLER Solar is the leading full service provider for the solar industry. We deliver a broad spectrum of technical solutions and services that guarantee a high-performance level and smooth running of a photovoltaic plant throughout its entire life-cycle. As independent PV experts with headquarters in Bremen and a branch in Waldkraiburg near Munich, as well as an office in London, we support manufacturers, operators, installers, technical advisors, insurance companies and banks with our expertise “Made in Germany”. Our service portfolio includes After-Sales Services, Inverter Services, PV Plant Construction, Test & Repair, Repowering, Claim Management, Engineering Consulting and EPC Management.

ADLER Solar employs 80 members of staff in Germany, Europe and Japan. Since 2015, ADLER Solar has been operating in Japan as part of a joint venture with YKD, ADLER Solar Works. In the same year, the Norwegian company Aqualis ASA and ADLER Solar Services GmbH entered into a strategic partnership.

For further information about ADLER Solar please contact:

Bettina Duske

Senior Manager Marketing Communications

+49-(0)421-835 701 00


For further information about Repowering please contact:

Sönke Jäger


+49-(0)421-835 701 90