While bifacial solar modules hog utility scale power plants and when combined with trackers, their impact becomes all the more noticeable, the industry is now exploring ways and technologies to further optimize this pairing, to further bring down overall levelized cost of electricity (LCOE). That comes at a time solar LCOEs slightly increased due to supply chain issues, although solar PV with trackers remains the lowest cost power generation source, according to BNEF (see Global Fixed Axis Solar Costs Go Up 14% YoY).
Day 2 of TaiyangNews Bifacial & Solar Trackers Conference on July 6, 2022 attempted to decipher the ongoing conversation into this domain. The speakers looked at the topics from the angles of a research institut (ISC Konstanz) a tracker supplier (TrinaTracker), a module producer (JinkoSolar), an encapsulation manufacturer (Hanghzhou First), and a software company (PVcase).
Sharing what's new in bifacial solar, Managing Director Advanced Cell Concepts and Member Executive Committee at ISC Konstanz, Dr Radovan Kopecek took the audience through the natural evolution of solar PV technology.
Kopecek said in the last 2 years there has been a spurt in the use of bifacial solar panels and there is a growing market for this technology even beyond utility scale, mentioning for example even balcony solar applications, among others. While currently it is bifacial PERC that rules the roost, n-type crystalline silicon PV will be the 'new emperor' of energy markets from 2025 onward.
What works for n-type is its ability to offer higher bifaciality and lower degradation value, therefore bifacial nPV that's more suited for hot climates. To optimize bifacial solar, developers will also need to work on standards and albedo enhancements like Jolywood did for the 500 MW Ibri II project in Oman (see 500 MW AC Ibri II PV Project Online In Oman).
Launched in May 2022, SuperTrack Smart Control Monitoring from Trina Solar's TrinaTracker is aimed at improving energy yield of projects by up to 8%. Head of Solutions Sales for EMEA, TrinaTracker Oscar Aira discussed how this system improves power generation with its intelligent working.
Listing its features, Aira said the SuperTrack Smart Control Monitoring enables low LCOE with its smart tracking and backtracking algorithms as opposed to conventional tracking algorithms, meteorological data sharing that leads to high reliability for solar installations. For bifacial modules specifically, it optimizes power production in highly diffuse irradiance conditions.
A key proponents of commercializing n-type TOPCon cell technology, JinkoSolar's Manager Song Li talked about the company's choice of this technology. He counted higher power warranty of 30 years as compared to the traditional p-type module with the 1st year degradation being lower than 1%, and maximum bifacial factor reaching 85% compared to p-type's 75% that leads to significant power gain by around 2.03%. The power yield will further go up in case of high temperatures.
Sharing the company's cell efficiency roadmap, Li said p-type PERC has reached the efficiency limit of 24.5%, and now it is time for n-type for which JinkoSolar aims to exceed 26% by 2023.
Hangzhou First's R&D Engineer Steven Tang deliberated on packaging solutions for bifacial n-type module from the reliability perspective. He presented the possible reliability concerns with TOPCon modules and the encapsulation solutions of the company, particularly TF4N POE that showed strong resistance against finger corrosion.
Tang also referred to the company's high reflective black backsheet for monofacial modules using bifacial cells, and claimed that even though it is black the backsheet will reflect the light. In addition to providing a pleasant all black appearance, the reflective black backsheet results in 2% power gain, at par with the white variants, he added.
As solar projects become more technically complex, the models used to simulate these do not always work as accurately leading to underperforming assets. This can eventually hamper the yield and the financial prospects, explained Lithuania based software company PVcase's Market & Insights Analyst Miguel Herrero.
Herrero said his company's 'revolutionary' and 'more realistic simulation' PVcase Yield estimation software developed with solar cell testing and simulation leader IMEC, a Belgium based research institute, calculates the performance of each string in the PV plant instead of assessing 'lumped performance'.
The 3D ray tracing used by the software is adapted to large scale solar which Herrero called a 1st in the industry: it resolves at cell level the effects of partial shading due to surrounding objects and albedo and can be used for any plant size.
Executive Panel
Moderated by TaiyangNews Managing Director Michael Schmela, the executive panel discussion revolved around optimizing solar power plant's LCOE using bifacial and solar trackers.
TUV Rheinland's Global Segment Coordinator Solar, Christos Monokroussos recalled the initial period in 2016-17 when bifacial modules were being tested, and in a short span of time, these have come into mass production. Today these have a variety of applications. The good thing is there are less failures being reported for these installations.
There is increased consolidation in the industry hence companies with experience and expertise in PV technology are mostly seen in the market. There may be a few new entrants coming in as Europe and other markets tend to build their local supply chains, but so far there is no major generalized dip in quality seen.
Chinese tracker supplier Antai Solar's Global Engineering Director Emmanuele Chiappori expressed concern at manufacturers and developers trying to curb costs even where it is not necessary to, and this may end up harming a project's prospects even though it may look good on paper. He said the key is to invest in technology to build really solid projects that can last their lifetime of 25-30 years. As for trackers, he believes there needs to be in-depth studies into the role of trackers in helping improve yield of bifacial modules.
According to Dr Radovan Kopecek of ISC Konstanz, in 5 years from now, there will be a mix of PERC, HJT and later on IBC solar cell technologies that use n-type modules as well as trackers because these contribute to bifaciality and therefore better power generation. While there will be much more n-type, he does not see the end for PERC in 5 years.
The day 1 of TaiyangNews Bifacial & Solar Trackers Conference on July 5, 2022 explored the winning combination of bifacial solar modules and solar trackers (see Bifacial & Solar Trackers Conference Day 1).