Expert advice, analysis, troubleshooting and expert reports

HaWe Engineering GmbH supports you professionally and independently in the quality assurance of your photovoltaic system. Our qualified employees will advise you from the evaluation of the site to the trouble-free operation – in Germany as well as worldwide.

In the field of photovoltaic engineering, we have specialized in the expert work. With yield forecasts and yield reports, we estimate the expected yield of your photovoltaic system at the specific location and depending on the selected module technology and system configuration. If required, you will receive an initial site assessment, a more detailed yield forecast or a well-founded and comprehensive yield report for your photovoltaic system.

Our scientific reports meet the requirements of the “self-obligation of the yield assessors” in the context of the uvs working group “Quality assurance for solar funds” and are recognized by all well-known banks.

Upon completion, our certified employees will create a commissioning report. In this way you start ideally into the operation phase.
This can also be secured by our services: We ensure smooth operation by thermographically measuring your plant. In this way, yield- and safety-relevant defects can be quickly identified and quickly and safely addressed by our detailed expert opinions.

Your advantages at a glance

  • Securing your investment and return on investment by providing scientifically based expert opinions
  • Asserting warranty and guarantee claims
  • Higher yields of the PV system by detecting and eliminating performance-reducing factors
  • Reliable measurement results through high-quality measuring equipment
  • High system availability and safe operation through proficient quality assurance
  • Short processing times due to many years of experience of our certified experts
  • Safeguarding of plant operation by eliminating relevant defects

Our expert service

Our expert services (reports, expert opinions, tests, measurements, evaluations, etc.) are carried out under consideration of the generally accepted rules of technology. According to the Energy Industry Act §49, compliance with the generally accepted rules of technology is presumed if the technical rules of the German Association for Electrical, Electronic & Information Technologies (VDE) are observed for systems for the generation, transmission and distribution of electricity (VDE) are complied with.


The professional acceptance of your PV-System is the requirement for a trouble-free plant operation.

An acceptance of your PV-system is espescially important for quality assurance. At best, the plant gets accepted immediately after commissioning. Our expert staff inspects the photovoltaic system and identifies possible deficiencies in design, execution, construction and potential production defects in individual PV modules and BoS electrical components.

Relieable operation of the system is only possible due recoginzing and repairing deficiencies early – also beyond the warranty period of the components. Our assessments and reports are robust and accepted by banks and courts.

Excerpt from our service catalog:

  • Check of the PV system documentation (according to VDE 0126-23-1)
  • Technical inspection and sighting on site (according to VDE 0100-712)
  • Measurement of current-voltage characteristics (U-I characteristics according to VDE 0126-24)
  • Photovoltaic thermography (according to IEC TS 62446-3)
  • Inspection of plant monitoring
  • Comparison of planning documents

Operational phase

Protect your return on investment by identifying and correcting deficiencies that affect returns.

Not every photovoltaic system produces the yields that were predicted in a yield forecast or profitability calculation during planning. If there is a relevant difference between the predicted and the actual yield value, it makes economic sense to carry out an error analysis.

Our employees have many years of experience in the measurement of PV systems of all sizes. They specialize in quickly and thoroughly discovering the causes of reduced yields in photovoltaic systems. The selection of suitable test measures and the use of state-of-the-art measuring technology in the inspection of your system leads to the shortest possible processing times. Among other things, we base our inspection on thermographic analyzes, operating data evaluations and characteristic curve measurements.

The following applies to every plant operator: The fewer errors that occur within a photovoltaic plant, the more yield can be achieved with the plant. We help you to find these errors and show you how you can optimize your yield. In this way, the predicted yield or profitability of your PV plant can be secured or even exceeded over the remuneration period.

Excerpt from our service catalog

  • Troubleshooting through photovoltaic thermography
  • Controll of the monitoringsystem
  • Operating data analysis
  • Warranty check
  • Performance analysis
  • Technical due diligence
  • Plant analysis
  • Damage assessment

Module damage

HaWe Engineering GmbH has documents and information on the subject of “failing module backsheet film” with references to the state of knowledge in the industry.

Some module manufacturers used unsuitable backsheet foils in 2010 – 2013, which show chalking and cracks over time, among other things. Detailed repair descriptions are now available from several manufacturers.

In the laboratory, therefore, the functional properties of the faulty modules are to be characterized and evaluated as the status quo, this includes

  • Insulation testing under wetting, IEC 61215-2:2016 (MQT 15)
  • Visual inspection, IEC 61215-2:2016 (MQT 1)
  • Characterization of the foil material

The insulation test is used to clarify whether modules with cracked back foil already lead to poor insulation. Falling below the minimum value required in IEC 61215 is considered a product defect.

The condition of the cracked backsheet, the delaminated and the discolored areas can be characterized by further tests:

  • Determination of pull-off forces at the weakest interface backsheet/EVA/cell or glass
  • Determination of the elongation at break of the backsheet

Strongly degraded adhesion forces can easily lead to delamination. Discolored areas – e.g. (yellowing, “browning”) – are also an indication of incipient degradation of the polymer, in advanced stages this can lead to adhesion problems.

Cracks in the backsheet indicate a decrease in elongation at break. Some backsheet materials used in PV applications tend to show severe degradation of elongation at break after exposure to UV, temperature and moisture. As a result, the material becomes brittle and cracks at points with increased elongation stress (e.g. along the cell edges).

TiO2 particles used as filler material can trigger photocatalytic degradation under UV weathering, which leads to leaching of the TiO2 filler from the polymer matrix and can be wiped off the back sheet as a white coating (dusting, “chalking”). In this case, too, degradation of the elongation at break and embrittlement of the material must be expected.