BIPV breakthrough from Spain: a semitransparent solar panel with tracking and micro-concentration improves power output and daylight transmission.
A new BIPV technology combines daylight with energy efficiency
A new innovation from Spain is reshaping the future of building-integrated photovoltaics (BIPV). Researchers at the Instituto de Energía Solar, part of the Universidad Politécnica de Madrid, have developed a semitransparent photovoltaic module that integrates a micro-concentration system and sunlight tracking. The result is a building-integrated panel that either boosts solar energy production or enhances indoor daylighting – without sacrificing aesthetics or space.
The potential of vertical surfaces for BIPV
BIPV technologies aim to generate solar power without using additional land, extending production beyond traditional rooftops. The next frontier? Vertical surfaces like windows and glass façades. These surfaces, however, require solar devices that can balance electricity generation with light transmission – and that can compete with traditional building-applied photovoltaics (BAPV).
Currently, semitransparent solar panels are among the most advanced BIPV solutions. These panels typically use double-glass structures with spaced crystalline silicon cells, allowing partial light passage. Alternative research is focusing on fully transparent or translucent modules based on organic semiconductors, dye-sensitized materials, or perovskites.
However, most of these technologies share a common issue: low power density and high production costs. Today, semitransparent PV modules can cost between €600 and €1,000 per square meter, with performance still lagging behind conventional solar panels.
A smarter BIPV solution with integrated tracking
The Madrid team’s breakthrough introduces a new kind of BIPV module that incorporates a smart micro-concentration system. Using narrow, flat linear Fresnel lenses with integrated tracking, the module focuses sunlight onto thin photovoltaic cell strips. These cells can also be paired with secondary optical elements to further boost efficiency.
Crucially, the panel features an intelligent daylight management system. The transparent backsheet allows diffused sunlight to enter the building with reduced glare. Meanwhile, the rear layer that houses the solar cells can move, adjusting the cell position relative to the optical focus based on sunlight angle and indoor lighting needs.
Strong results from early testing
The researchers report promising performance. “A peak optical efficiency of 76% is achieved, remaining above 60% for incident angles greater than 55° when using a secondary optical element,” the team notes. Photorealistic simulations show that the module delivers comfortable indoor lighting, surpassing conventional semitransparent BIPV panels in both illumination and power output.
To top it off, the system’s optical design is compatible with low-cost UV roll-to-plate printing, paving the way for scalable and affordable production.
