The reflective power of the ground proves to be decisive in increasing energy yield and optimising the latest smart solar cell systems

In the world of solar energy, there is a term that until a few years ago was known almost exclusively to physicists and climatologists, but which is now rapidly gaining a key role in the design of the most advanced photovoltaic systems: albedo.

This concept, which measures a surface's ability to reflect sunlight, is becoming a key parameter in optimizing bifacial panels, the new frontier of solar energy.

It's no longer just about installing modules in the sun: now the ground underneath also comes into play, becoming a key player in the production of clean energy.
Thanks to increasingly refined technologies, designers and companies in the sector are learning to "read" the landscape not in terms of exposure, but also in terms of reflectance, materials and geometry.

A silent revolution, but one with potentially enormous impacts on plant performance, energy costs, and the speed of the energy transition.

When the reflection of the future of the soil and the environment wins

Albedo literally means "to reflect": a surface with a value of 1 reflects 100 percent, one with 0 absorbs everything. In solar fields, natural terrain reaches between 10 and 30 percent, similar to meadows or cultivated fields; with snow or light surfaces, it can even exceed 50 percent.

In bifacial modules, the backside captures not only direct or diffuse sunlight, but also that reflected from the ground: a productivity gain of 10 percent to 25 percent, according to various estimates.

International studies on seasonal and spectral variability

International research has highlighted that albedo is not a fixed value: it varies with seasons, land use, snow cover, and even soil porosity and moisture. A team from the University of Calabria in Italy, in collaboration with the Aristotle University of Thessaloniki in Greece, has published a study in "Energy Reports."

Comparing simulations of roofs with albedo between 20 and 80 percent in Milan and Cosenza, the team found that, if the coverage exceeds 50 percent, the energy produced by bifacial modules can increase by up to 18 percent, thanks to the combination of reflections from the panels and the ground.

At the same time, advanced analytical models, such as those developed by MDPI and RINA, are introducing concepts such as “view factor” and “effective albedo” to correct errors in traditional calculations.

Experts: "Albedo changes within a few meters and days"

An interview with Solargis experts Vicente Lara Fanego (PhD, Solar Modelling) and Harsh Goenka (Business Development) underlines the urgency of sustained surveys:

"Albedo changes even within a few meters and days. An error of 0,1 can cause a difference of up to 4 percent in annual production."

The company Enertis Applus+ and the University of the Basque Country have also proposed high spatial and temporal resolution measurement technologies, integrating satellite data to reduce errors by 2-8 percent.

Practical solutions: how to increase existing albedo

Field options range from white polypropylene geotextiles to light-colored pebbles or sand: low-cost materials – US$1–2/square meter – that can increase albedo by up to 60–75 percent.

According to the IEA-PVPS study, targeted coverage under the modules is effective, but requires a fair economic compromise and constant maintenance to avoid decay due to dirt or UV rays.

An interesting example comes from Soltec's white paper: field tests in California, USA, showed gains of 15,7 percent with a 55 percent albedo and a 2P assembly on SF7 trackers; with medium albedos, the advantage drops to about 9,6 percent.

Designing Smart Systems: Height, Distance, and Geometry

Optimizing the albedo means integrating advanced design: defining the distance between rows, the height from the ground and the orientation, not only for the front but also for the rear.

Bayesian algorithms and LCOE optimization models show that standard slopes (equal to latitude) are not always optimal; the best combination can reduce LCOE by up to 23 percent.

In Monferrato or Tuscany, for example, increasing the module height by just 1 meter and on light soil allows for annual gains of more than 30 percent compared to plantings on dark soil.

Nicola Rossi: “An extraordinary opportunity for innovation

Nicola Rossi, Head of Innovation at Enel Green Power, said in an interview in 2025:

"The energy transition is an extraordinary opportunity for innovation. Thanks to digitalization, the use of new materials, and the synergy between renewables and emerging technologies, we can accelerate decarbonization and radically improve the efficiency of our plants."

"For us at Enel Green Power, which operates over 1.200 renewable energy plants worldwide, optimizing land use and increasing energy efficiency are key to achieving our sustainability goals. Hence the opportunity to use bifacial modules wherever possible and cost-effective, which can enable productivity increases of up to 10 percent compared to traditional modules."

adds the Italian company in a note.

Perspectives: artificial intelligence, continuous monitoring

The frontier now is AI: automated measuring stations, orientable albedometers, drones, and IoT sensors allow for real-time data acquisition and adjustment of parameters such as trackers or soil irrigation.

Systems like those from Enertis or Solargis will soon be able to influence industrial-scale projects, identifying high-potential surfaces even before installation.

Albedo represents a fundamental lever in the evolution of solar energy. With advanced geometries, selective reflective materials, and accurate measurements, a new era of innovation is dawning.

Adequate investment in research and experimentation will allow simple solar fields to be transformed into highly efficient plants, with tangible climate and environmental benefits: less land consumed, more energy produced, and lower emissions.

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