Joining efforts for extensive Adaptation of Novel bifacial modules in Utility-scale Solar

In this project, Scatec Solar and IFE will investigate the use of two-sided (so called "bifacial") solar cells for use in large scale solar power plants. Bifacial solar modules can produce more electricity than traditional modules by harvesting sunlight from both sides, and they can therefore also produce energy from light reflected from the ground and the surroundings. To produce even more energy, bifacial solar modules can be combined with trackers, helping the PV modules to follow the path of the Sun across the sky. The price of such bifacial solar modules has only recently become low enough to be used in large scale solar projects, and in 2019 Scatec Solar opened the World?s first large-scale PV power plant based on bifacial modules in combination with trackers. The Benban plant in Egypt, where 390 MWp of bifacial PV modules are mounted on 1-axis trackers. consists of ~1.1 million bifacial PV modules, corresponding to ~78 million individual monocrystalline silicon solar cells! This plant alone produces 930 million kWh of clean electricity per year, enough to power 420 000 households with an estimated saving of 423 000 tons of CO2 emissions annually. This innovation project will help Scatec Solar and IFE understand the gain in production enabled by bifacial solar modules and build experience of how such solar power plants should be built and operated in the most efficient manner. This will give Scatec Solar an important competitive edge and an opportunity to continue growing into the demanding global PV market. It is well known in the literature that the market-leading simulation tool PVsyst underestimates the irradiation that is incident on the rear-side of bifacial modules mounted on trackers. To confirm this, simulations must be compared with irradiance measurements carried out along the rear-side of the modules by pyranometers or reference cells. Results from PVsyst have been compared with similar results from several simulation tools with different working principles and level of detail in the modeling. Such a comparison rely on uncertainty estimates that support the statistical confidence that can be attributed to any discrepancies between simulations and measurements. We have developed a new methodology for estimating such measurement uncertainties from measurements made with many pyranometers distributed across the solar power plant. Such an uncertainty estimate is also important for assessing spatial and temporal variations in albedo and the irradiance incident at the rear-side of the modules measured in bifacial solar power plants. Based on this, we have developed a new method for calculating these quantities and assessing their statistical significance. Calculating the increase in electricity production due to the use of bifacial solar cells rather than monofacial solar cells is complicated. Special emphasis has been placed on developing a detailed methodology for making such calculations. Insights that have been gained in the project have been presented publicly on four occasions. During The Norwegian Solar Cell Conference in Son, results from IFE's bifacial test facility at Kjeller were presented. Moreover, during a webinar held by The Norwegian Solar Energy Cluster, Scatec presented their experiences with bifacial pv. In the same webinar, IFE also presented an example study where front and rear irradiation was simulated with both PVsyst and the more detailed ray-tracing software bifacial_radiance. The results were compared with measurements made in several locations along the front- and the rear-side of the modules. Finally, results will also be presented at the European Photovoltaic Solar Energy Conference and Exhibition (EUPVSEC) in Lisbon, Portugal 18. - 22. September 2023.This work focus on spatial variations in albedo in a utility-scale bifacial PV power plant and this variations impact on energy-yield simulations.

Ved begynnelsen av prosjektperioden var det lite etablert praksis både for design og drift av tosidige solcelleparker og kunnskapsbehovet var stort. Det var usikkerhet knyttet til effekten av albedo, drift av albedo målestasjoner, behov for vasking av baksiden, tap knyttet til stygge fra bakside strukturer og tap knyttet til elektrisk mismatch. Det var også usikkerhet knyttet til presisjonen til ulike simuleringsverktøy som brukes til å beregne innstrålingen på baksiden av modulene. Dette er faktorer vi har fått kunnskap om i løpet av prosjektperioden. Etter 3 år tar tosidige solcelleparker stadig nye markedsandeler, og Scatec leder an i denne utviklingen. Kunnskapen Scatec har tilegnet seg gjennom dette forskningsprosjektet sammen med operasjonell erfaring gir Scatec nå har en kompetitiv fordel og mulighet til å vokse i et krevende globalt marked. Enkelte resultater, som degradasjonsraten og tosidighetsgevinsten, kan ikke deles med offentligheten grunnet sensitivitet. Metodikkene som har blitt utviklet vil imidlertid bli publisert på sentrale konferanser og i fagfellevurderte tidsskrift. Dermed vil også prosjektets resultater være nyttige for forskningsfeltet.

This innovation project will help Scatec Solar realize a large potential for value creation by increasing the use of bifacial solar modules in future PV projects. A bifacial solar module can produce more electricity than a traditional module by harvesting sunlight from both sides, thereby also taking advantage of light reflected from the ground and its surroundings. Although such cells are not new as a concept, bifacial solar cells have only recently obtained appreciable shares of the market. While laboratory tests clearly show the potential of bifaciality to increase production, important questions remain about field performance. As for many other anticipated innovations in the photovoltaic (PV) industry, lack of data and standards contribute to substantial financial risk. To change this situation, and to allow the Norwegian solar energy producer Scatec Solar to benefit from its current pole position in the industry shift to bifacial technology, there is an urgent need for research on this topic. This innovation project will give a solid data foundation to understand the gain in production enabled by bifacial PV, the required conditions to realize this gain, and build experience of how component performance and degradation compare with conventional systems. The core of this project is Scatec Solar’s innovative Benban Solar Park, where single-axis trackers and bifacial PV modules are combined in utility-scale production for the first time in the world. This pioneer project provides unique production data, enabling the proposed innovation project to break completely new ground. By limiting uncertainty of future investments, thus reducing both financing costs and project development time, Scatec Solar will remain a highly competitive bidder in the utility-scale PV market. This will give Scatec Solar an important competitive edge and an opportunity to continue growing into the demanding global PV market.