25 October 2019

PVmoduleTech 2019: The need for accurate performance measurements

Recently, PV-Tech took the opportunity to catch up with Erik Bentschap Knook, Chief commercial officer at Eternalsun Spire and a key partner at the forthcoming PV ModuleTech 2019 in Penang.

We talked about some of the new industry trends in module manufacturing and technology, and how Eternalsun Spire has been working to address these trends.


What have been key industry trends in the sector this past year and how has Eternalsun Spire addressed these trends?

Erik Bentschap Knook: "A major key trend this year is that the industry is becoming more aware of PV module performance outside of "Standard Test Conditions". Temperature related and short term degradation effects like LID/ LeTID get much more attention from PV manufacturers. This is mainly driven by the downstream market which is quickly becoming more quality aware. Especially, temperature related performance parameters like temperature coefficients gain more importance as they have a strong effect on yield in different regions. Measuring temperature coefficients accurately has been a challenge for PV industry and recent round robins show up to 10% uncertainty. In some cases, every 10% of measurement uncertainty leads to 1% of yield loss every year.

Our mission is to contribute to the growth of solar industry by providing the most accurate performance measurements to reduce the industry’s safety margins. Through smaller safety margins, less money is left on the table, which will be key to protect profit margins in this price competitive industry. Over the past year, Eternalsun Spire developed a dedicated testing process to decrease measurement uncertainty of temperature coefficients by 50%."


So, how can Eternalsun Spire decrease measurement uncertainty of temperature coefficients and how is that different for high efficiency modules?

"Uncertainty in measuring temperature coefficients is driven by solar simulator light quality and unstable, non-uniform temperature control. With the introduction of high efficiency modules, many sun simulators are inadequate to measure the power output accurately. They have too short of a light pulse and do not have the UV and IR spectrum that is required. On top of that many traditional set-ups cannot control and especially stabilize temperature. The two effects combined lead to very inaccurate results.

At Eternalsun Spire we developed a system and testing method with the goal to decrease measurement uncertainty of temperature coefficients. Unlike traditional test set ups, we introduce an accurate way to measure temperature coefficients, achieving reduction of safety margin by half. The set up combines the Spire Single Long Pulse laboratory flasher with a temperature control chamber which is placed on top of the flasher. The system has 270ms Single Long Pulse duration and extended spectrum from 300nm to 1200nm according to IEC 60904-9 ed.3 to test performance parameters of existing and future high efficiency modules. The temperature chamber enables 10-85C temperature range with -/+ 1C temperature uniformity, which is extremely uniform and can be held exactly stable."


How is Eternalsun Spire involved in bifacial PV module testing & characterization?

"At Eternalsun Spire, we have two active members within the IEC TC82 WG2, in charge of IEC 60904-1 standard regarding IV measurements of bifacial PV devices and we have actively contributed to its development by conducting scientific research on single side illumination vs double side illumination test methods for bifacial commercial size PV modules. We are also participating in an inter-laboratory Round Robin for bifacial PV module measurements at OdinSpire, our bifacial-ready test laboratory in the harbor of Rotterdam.

In addition, we recently published a joined article with CEA INES with insights on how to accurately measure the efficiency of bifacial HJT modules. We are proud that leading R&D institutes have recently decided for our single long pulse technology, as it allows them to do a real measurement of even the highest efficiency technologies, including bifacial PV, without need of correction methods required for shorter pulses, which add uncertainty to the maximum power measurement."


How can Eternalsun Spire help module buyers make informed purchasing decisions?

"We suggest module buyers to challenge the manufactures and become more aware of the quality of the selected modules. Eternalsun Spire can provide the tools and application knowledge to energy companies, EPCs, installers to do supplier and product evaluation for their PV projects. For this purpose, we set up OdinSpire, a quality inspection PV lab in Rotterdam harbor in the Netherlands. At OdinSpire we support module buyers to test the quality and power output of imported modules before installation. We perform a wide range of quality testing services such as performance at STC, temperature coefficients, energy rating, LeTID."


We noticed you made a slight name change. Can you elaborate why?

"We decided to merge the two brand names as we are the combination of an innovative, young company - Eternal Sun - and an industry recognized name with broad experience company - Spire Solar. This combination creates a unified environment to keep developing innovative and high quality solutions for our customers."


What are you looking forward to hearing about at PV ModuleTech 2019?

"PV ModuleTech is a great platform to meet with key players from the PV module value chain. The conference gives us the opportunity to discuss with a wide range of industry experts and further improve our solutions for quality control of existing and future PV module technologies."


source: pv-tech.org