TU Graz's foldable PV system delivers up to 56 percent more electricity

Technical core: Linear actuator

Buchroither describes the technical core as follows: "Kerninnovation des Systems ist ein patentierter linearer Aktuator, der die Anlage sowohl zur Sonne ausrichtet als auch zusammenfaltet." This linear drive allows the module surfaces to follow the sun's position and, when needed, to be folded together in a space-saving and protected manner. According to the Graz research team, this is a dual function that addresses both electricity production and protection of the system.

Compared to fixed-mounted PV modules, the pivoting and foldable solar system delivers an average surplus yield of just under 40 percent, according to the project leadership. On individual days, up to 56 percent more yield was achieved. These figures are based on measurements at the demonstration system operated by the institute on the Inffeldgasse campus.

More electricity in the morning and evening hours

According to Buchroither, the additional electricity yield during the margins of the day is decisive for economic viability: "Morgens und abends, wenn der allgemeine Stromverbrauch besonders hoch ist, liefert sie durch das optimale Sonnenstand-Tracking mehr als doppelt so viel Strom wie traditionelle PV-Anlagen, was auch zur Netzentlastung beiträgt", the Graz group leader emphasized. With this, TU positions the solution as a contribution to stabilizing the electricity grids during high-load morning and evening hours.

A second advantage lies in weather protection. "Bei Sturm- und Regengefahl klappen die Module 'face to face' zusammen und werden horizontal - mit den Rückseiten nach außen gerichtet - gelagert", the project team stated. Through this protective function, damage from storms, hail, or heavy rain is to be reduced, and locations for solar systems that would not be feasible with rigid modules are to become usable.

Storm protection and cost advantages

The design also promises economic advantages. Buchroither explained: "Durch diese Doppelfunktion sparen wir Installations- und Betriebskosten, wodurch sie die Wirtschaftlichkeit verbessert". By combining tracking and storm protection in a single mechanical system, the need for separate protective structures is eliminated, which is expected to lower the system's overall costs.

With the demo system on the Inffeldgasse campus, the Institute of Electrical Measurement and Sensor Systems aims to show that tracked photovoltaics can also be implemented on urban rooftops. The researchers see this as an approach to advance the energy transition in densely built areas, where installation space is scarce and weather exposure is often high.

Outlook on scaling and market

It remains open how quickly the technology can be scaled into the market. Further testing phases, discussions with industrial partners, and possible licensing of the patented actuator are typical for such research projects. Concrete steps toward serial production cannot be derived from the available information.

Overall, TU Graz points to an average value of about 40 percent surplus yield over fixed-mounted systems and to daily peaks of 56 percent. Whether these values are reproducible under other climatic conditions will need to be shown by future measurements at additional sites.

The research work is part of the activities of the Institute of Electrical Measurement and Sensor Systems at TU Graz. Buchroither and his team see the combination of tracking and folding mechanics as an option to increase the area productivity of photovoltaics while simultaneously improving robustness against extreme weather events.