The efficiency of a solar module is its ability to convert the incident solar light into electrical energy per unit area. And the average efficiency of a solar panel has been ever increasing with many advancements taking place at both the cell and module levels.
TaiyangNews has been publishing the listings of top commercial module efficiencies as part of Advanced Module Technologies reports. However, the efficiencies were published separately for 60 and 72-cell modules in the past. Since efficiency is not dependent on the number and size of cells, and with all leading module makers offering their top products in both the cell configurations, this year's TaiyangNews Report on Advanced Module Technologies report simply lists the top efficiency modules independent of any such area factors. And, we have increased the minimum qualification to 21% against 20% in the 2019 report. Note that we have listed only the top module from each cell technology stream of one module maker.
With this revised criterion, according to our research (status: December 2020), a total of 21 products from 18 different companies have made it to our list this year. Our previous report consisted of 17 and 16 products in 60 and 72-cell configurations respectively.
Our research pegs the highest commercial module efficiency at 22.7% for a back-contact module from Maxeon. These Maxeon 3 series modules feature SunPower's proprietary IBC technology implemented on 5-inch n-type wafers. The module is built with 104 of such Maxeon Gen 3 solar cells. The US/Chinese company has scaled up the technology to the M4 wafer format, marketed as Maxeon 5 series, which achieved a maximum efficiency of 22.5%. This product though doesn't find mention in this top efficiency segment, according to the note above. Maxeon does take the second place as well, as its Performance series, based on PERC technology at the cell level and employing shingling for interconnection, attains the second best efficiency of 22.5%. This module series is built on the G1 wafer format.
An HJT module from Suntech featuring half-cell, MBB and bifacial technologies comes in third with an efficiency of 22.1%. It is somewhat surprising though that Suntech is able to offer better module product over its much established peers despite its reliance on external sources as it doesn't have its own HJT cell production facility at least as of now. The MBB and half-cell module from Jolywood based on TOPCon cell technology attained 22% module efficiency, a level also reached by an IBC module from LG.
The simple mantra of employing cells based on high efficiency cell architectures is true for the above top-rated products, but doesn't necessarily apply as we go down the efficiency list. This is demonstrated by one of GCL's PERC modules, which achieves a rated 21.9% efficiency with just a combination of MBB and half cells. It is a large module built with 156-half cells (78 eq.) of 182 mm edge length, and thus also has a high-power rating of 610 W. Not just GCL, products from 11 more suppliers based on simple PERC cell technology and a combination of half cells and MBB at the module level have efficiencies of over 21%. JinkoSolar's Tiger Pro series using Tiling Ribbon technology and Trina Solar employing 3-cut format are using a bit more advanced module technologies to reach 21.33% and 21.2%, respectively.
A common attribute of these high-efficiency modules using standard PERC cells is that they all are based on very large wafer formats as of today – either 182 mm or 210 mm edge length. While it sounds counterintuitive, the approach of increasing the wafer size is actually helping to improve efficiency. One of the main reasons is that all larger wafers are made using the latest generation production tools based on advanced technologies at all stations of the process chain – from wafers to modules. This results in high-quality raw material for cell lines, which are processed using brand-new machines at the cell level as well. Process uniformity and control are at their peak – the end product of superior quality. These larger wafers are also compatible with advanced metallization layouts, such as MBB.
Among the companies offering modules based on high efficiency cell technologies, REC and Risen are promoting products based on HJT technology with efficiencies of 21.7% and 21%, respectively. SPIC and FuturaSun are promoting IBC modules in half cell layout with efficiencies of close to 21.3% and 21.1%, respectively.
NOTE: The data for the products in the table above is taken from specs provided by the companies along with data sheets (status: Dec. 2020).
For detailed information about module products and efficiencies, please download and read TaiyangNews report on Advanced Module Technologies 2021, which can be downloaded for free here.