Hamza Samdi

PV Module Power Increase: A Glance Behind the Scenes

PV module manufacturers compete to increase the power generated per PV module under STC conditions; this is not only to meet the demand.

PV Module Power Increase: A Glance Behind the Scenes

PV module manufacturers compete to increase the power generated per PV module under STC conditions; this is not only to meet the demand.

Hamza Smadi

May 6, 2020

Power per PV module is a significant factor when choosing a manufacturer to supply PV modules. PV module manufacturers have been competing to increase the power generated per PV module under STC conditions. This is not only to meet the demand for higher power PV modules but also to reduce the manufacturing cost per Wp. A brief introduction to the wafer classifications must be provided to understand the relationship between increasing the PV module power rate and the manufacturing details.

Before 2010, most of the PV module manufacturers were using small size monocrystalline 125mm width cells. After 2010 the well-known 156mm wafers were used vastly; very few manufacturers were still working with the 125mm wafers until 2014 when the p-type of such wafers disappeared from the market. In 2013, M1 (156.75-f205mm) and M2 (156.75-f210mm) wafers were introduced by LONGi, Zhonghuan, Jinglong, Solargiga and Comtec in a standard release. These wafers were the mainstream in module production until 2017. The M2 wafers achieved a power increase per module up to 5Wp without changing the module size. Last year, the G1 (158.75 mm) wafers were used by giant Tier-1 Chinese module manufacturers. On the other hand, M6 (166mm) and M12 (210mm) wafers were adopted by overseas manufacturers such as Hanwha Q-Cells.

Increasing the power generated per PV module decreases the manufacturing cost. Thus, the volume of the annual shipment rises for the same number of modules manufactured compared to previous years. Seeking more power per PV module is facing a milestone. Increasing the module efficiency beyond 21% is the bottleneck that most module manufacturers face while trying to meet the market demand on higher power PV modules.

PV-TEC Back End: Wafer in firing furnace. The PV-TEC Photovoltaic Technology Evaluation Center inaugurated in 2006 at Fraunhofer ISE was the first non-Profit R&D laboratory in the field of crystalline silicon solar cells based on large scale and mostly automatic equipment. Copyright: Fraunhofer ISE / Dirk Mahler

Many manufacturers began to produce high power modules by changing the module dimensions. Until 2018, most of the PV modules had their 72 solar cells stacked in a 1.940352 m2 module with power around 380W@ 19.58% module efficiency. Nowadays, manufacturers produce 144 Half Cut Mono PERC cells in a 2.209184 m2 module with power up to 450W@ 20.37% module efficiency. Such an increase in module power is not directly related to solar cell efficiency development; instead, it is thanks to the increase in module dimensions, which is around +12.16%.

All in all, high power PV modules are beneficial in reducing the LCOE for commercial utility-scale projects and minimizing the BOS costs, such as mounting structure material, installation costs, project installation time and land requirements. On the other hand, the relationship between increasing the module power and the decreasing the manufacturing costs will soon reach a saturation period. Then, we will have to wait for more cell efficiency development to break the 21% module efficiency barrier. It is inevitable when the current market technology/price stream is considered.

References:

Canadian Solar. HiKu & HiDM Series, https://www.canadiansolar.com/. Accessed 6 May 2020.
Jinko Solar. Eagle & Cheetah Series, https://jinkosolar.eu/en/. Accessed 6 May 2020.
LONGi Group. https://en.longigroup.com/. Accessed 6 May 2020.
Osborne, Mark. "Updated ITRPV highlights solar wafer size transition and processing tool throughput issues." PV Tech, 4 Nov. 2019. https://www.pv-tech.org/news/updated-itrpv-highlights-solar-wafer-size-transition-and-processing-tool-th. Accessed 6 May 2020.
----. "Why are monocrystalline wafers increasing in size?" PV Tech, 8 Jul. 2019. https://www.pv-tech.org/editors-blog/why-are-monocrystalline-wafers-increasing-in-size. Accessed 6 May 2020.
PV InfoLink. "Wafer trends for 2020: Transitioning to larger size." InfoLink, https://www.infolink-group.com/en/solar/analysis-trends/Wafer-trends-for-2020-Transitioning-to-larger-size. Accessed 6 May 2020.
Saur News Bureau. "Longi Solar Explaining the Larger Size of Mono Silicon Wafers." Saur Energy International, https://www.saurenergy.com/solar-energy-blog/longi-solar-explaining-the-larger-size-of-mono-silicon-wafers. Accessed 6 May 2020.
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