Online Interview with Tüv Rheinland

As a German-capital-company TÜV Rheinland, active in 65 countries with a long-standing corporate history of more than 140 years, is working for providing services with the best and highest quality standards in several fields, which are Product Safety Tests and Certification, System Certification, Industrial Services, Training and Consultancy.

TÜV Rheinland is also active on solar energy. With its comprehensive service offerings, the company supports each sector of the photovoltaic marketplace – from supply chain to investment and installation – from initial manufacturing to final product. Thanks to this broad activitity scope, TÜV Rheinland provides the local support, with global market access reach.

To find informative answers for common questions on solar energy (its future, qualities and investment variables) we have directed our questions to TÜV Rheinland that have broad network of expertise in every segment of the solar energy industry and long standing experience. Joerg Althaus, TÜV Rheinland’s Regional Field Manager Germany and IMEA, has provided a lot of comprehensive information about solar industry from the TÜV Rheinland’s perspective.

1) Could you please shortly make an introduction for TÜV Rheinland Energy department?​

TÜV Rheinland is a world leader in testing and supply chain management services for the solar industry. With over 35 years of experience, TÜV Rheinland offers a global presence, industry expertise and a wide-range of comprehensive services to address the challenges of the solar market. TÜV Rheinland is well positioned to support PV module and component manufacturers with all of their testing and certification needs, including inspecting and auditing production lines and PV product quality, and power measurements regarding degradation modes of PV modules. As an independent third-party, TÜV Rheinland’s world-wide organization has you covered when it comes to supply chain management. TÜV Rheinland is also ready to support independent engineering for PV power plants, including development, design, construction and operation of the plant. With over 250 PV experts located around the globe, TÜV Rheinland can cover the full PV power plant value chain, including pre and post shipment, no matter where you are located. TÜV Rheinland’s technical and engineering expertise coupled with a comprehensive understanding of the investment needed to support power plants establishes the company as a world leader in customer service and satisfaction. The global network of TÜV Rheinland laboratories is located in all major solar hubs, including: China, USA, India, Japan, Middle East and South America. For more information, please visit:

2) What is the main function of PV-Lab’s of TÜV Rheinland?​

Our labs have two main functions:

– On the one hand we are testing and certifying PV modules, PV components, inverters, energy storage systems for manufacturers acc. to international or national standards to provide them with global market access.

– On the other hand we are providing supply chain management services, which means, we perform factory audits, production audits, pre-shipment audits and quality control tests on samples picked from the factories. E.g. if an EPC buys PV modules from China for a project in MENAT, we would be picking PV modules in accordance with AQL level and check Mpp power, gel content, electroluminescence measurements, etc.

3) Everyone is talking about the end of the fossil-fuel era, what next? Are we gonna really head for renewables or is nuclear power and others still a strong option?​

It is clear, that we have immense growth in RE and will have for the next decades. RE are a necessity and are in many cases already he financially more feasible option vs. other technologies. Looking forward there is no reason to believe, that the positive cost development will change to a less competitive situation.

4) Is solar really sustanable? What are the real costs and return on investment expectancy?​

As with any investment, the sustainability and profitability depends on good planning and quality assurance. Solar projects that are well planned and where the business plans are built on good validated data are very successful. On the other hand, we are involved in many cases, where quality control and technical understanding was lacking, causing big gaps between predicted energy yield and real yield. Involving an experienced technical advisor and implementing quality control measures is key to success with large scale PV projects.

5) Which problems do you encounter most? What are your suggestions for dealing with them?​

In many cases investors or developers trust on documents and minimum requirements rather than requiring concrete quality control through a sound contract with their suppliers. This may lead to underperforming PV modules or fast degradation of components. We see non-compliance with codes and good practice in a majority of PV systems. Many of the issues turn out expensive to fix, but are easy to avoid.

6) H​ow is the quality processes of the manufacturer correlated to the quality of the solar module?​

It is important to state, that a quality certificate in accordance to international standards is only a minimum requirement. Many manufacturers do more than expected from a standard point of view. However a certificate does not replace the requirement for per project quality control. It is highly advisable to require independent inspections and sample testing per PV project, to have a good understanding on the actual quality status.

7)​ What would be your Top 5 suggestions for the solar power plant investors?​

  1. Make sure you know and fix the Bill of Material (BoM) of the modules your purchase
  2. Impose third party quality control measurements on your suppliers
  3. Understand the local soiling conditions and adjust cleaning cycles
  4. Make choice of technology based on local conditions (temperature dependence)
  5. Base your performance ratio (PR) and degradation assumptions on valid data