Soltec spearheads research in bifacial solar tracking

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Soltec manufactured its first tracker designed for the mounting of bifacial panels in Chile in 2015 and in 2018 opened a bifacial tracking research centre in California. Such commitment is easy to explain: a bifacial solar tracker harvests energy from both its front and rear side, capturing the sunlight reflected on the ground. And under the right conditions, yield will increase by more than 30%.

The standard features of the SF7 solar tracker from Soltec provide bifacial compatibility due to the higher mounting height, a shadow-free backside and wider service aisles between tracker rows. These features mean that the bifacial modules are further off the ground, reducing the intensity of the shading on the tracker itself while enhancing bifacial gain. It also avoids the main disadvantage of most solar trackers: the axis casting shadows on the backside of the bifacial panel.

The double-width aisles between the SF7 tracker rows help increase the capture of the albedo reflected from the ground and from the solar modules of adjacent trackers. Wider aisles also facilitate the passage of array washing and vegetation control vehicles, thereby reducing O&M costs.

The SF7 Bifacial harvests energy from both its front and rear sides, as it captures the sunlight reflected on the ground beneath the solar tracker. Given the right conditions, energy production increases by more than 30%. The solar tracker from Soltec has recently been supplied for a solar project in the Israeli region of Merhavim and Bnei Shimon. The project has a total capacity of 17 MW, of which 2 MW is produced by bifacial modules. The plant is equipped with a total of 534 units of the SF7 Single-Axis Tracker and 64 units of the SF7 Bifacial.

As Emilio Alfonso, commercial vice-president of Soltec for the EMEA region, explains: “the main challenges of this project stem from the extreme weather conditions inherent to a high altitude, desert location. Logistics created challenges when complying with the works schedule, given its location a long way from urban centres and main roads. Fortunately, our experience allows us to successfully work under this type of conditions”.

Pioneers in bifacial tracking

Soltec is a pioneer in bifacial tracking. By 2015 it had already manufactured the first tracker specifically designed to be mounted with bifacial panels for a plant located close to the La Silla European Southern Observatory in Chile. This 1.72 MWp PV plant is for experimental purposes and represents the innovation, research and development invested, making the La Silla solar tracking plant an exceptional project.

Promoted by the Italian developer Enel Green Power, with Soltec responsible for its installation and design, this plant is located on the fringes of the Atacama Desert, in the region of Coquimbo. The site stands at an altitude of 1,800 metres and covers half the energy demand of the European Southern Observatory. Its location is no coincidence for an experimental installation of this type, given that the clean atmosphere of the area facilitates the research work.

The project, which continues to be the only one of its type in the world, incorporates major PV industry innovations. Two different types of trackers have been used for three different types of modules with the aim of analysing both efficiency and productivity. For this, Soltec has specifically designed two different tracker models to maximise the production of the modules used: in the first place, conventional polycrystalline; and secondly, polycrystalline with electronic optimisation which improves efficiency under certain conditions. Lastly, bifacial technology which is the most important type of module at this solar plant.

As a result of this project, Soltec has developed the first solar tracker with bifacial modules specifically designed for industrial plants. This tracker maximises the PV yield of the bifacial module thanks to the fact it makes use of the solar energy reflected on the ground. Bifacial panels have the capacity to harvest this diffuse energy. For conventional modules and optimised modules, Soltec has designed and installed a solar tracker configured with 4 rows of 19 modules in a horizontal layout.

Moreover, the standard design of the solar trackers from Soltec offers one of the highest tolerance levels to gradients on the market: up to 17% in a N-S orientation, thereby minimising earthworks, trench laying and internal roads. The selected configurations create spacious aisles which make O&M work more efficient.

The entire implementation and development of new technologies reflect the research mission of the plant. The project developer, Enel Green Power, decided to use this plant as an experimental field in which to test different technologies under real conditions in order to improve the future of PV production.