Switzerland: Growers Day highlights tomato production under spectral filtering

Last week Voltiris, the Swiss-Dutch greenhouse energy company, welcomed more than 40 growers from Switzerland, Germany, France, the Netherlands, and the UK to Meier Gemüse in Rütihof for a dedicated Grower Day. The event offered a firsthand look at the world's first hectare-scale spectral filtering solar installation, with nearly 2,000 Voltiris modules installed across an entire hectare of cherry tomatoes.

Voltiris develops solar technology specifically designed for greenhouses, allowing growers to generate renewable energy without compromising crop performance. The visit demonstrated a clear and simple message for growers — strong crop production and on-site clean energy production go hand-in-hand with the Voltiris system.

Strong results point to practical benefits for growers
The event opened with presentations from the Voltiris team and Ruedi Meier, owner of Meier Gemüse, who shared results from the installation. The greenhouse has been producing up to 1 MWh of renewable electricity per day, while maintaining stable crop production, with a +1% yield increase compared to the reference compartment. Leaf temperatures were reduced by 3°C on average during sunny periods, helping tomatoes stay within the optimal temperature range of 20–25°C. In the Voltiris compartment, crops remained in this ideal zone 74% of the time, compared to 57% in the reference. Crops under the modules rarely exceeded a plant temperature of 28°C, safeguarding proper pollination and fruit set. With the system in place, Meier Gemüse has reduced summer grid electricity use by around 35%.

© Voltiris

The installation works were executed smoothly during four weeks in May, without interrupting production. Or as Ruedi Meier put it: "I was able to peacefully work from my office during the installation period, which says it all".

During the summer of 2025, Meier's harvest crews chose to harvest under the Voltiris modules during the hottest hours of the day, to benefit from the heat reducing effects of the system.

© Voltiris

The highlight of the day was a tour of the greenhouse. The visiting growers observed the modules overhead, examined the plants directly, and discussed how the system performs in daily production.

"Seeing the large-scale installation really shows how well the system adapts to light capture — it's very clever and easy to install," said Charlène Richard-Breyne, Head of the Energy Division at Cerafel, Prince de Bretagne, one of the leading fruit and vegetable cooperatives in Brittany, France.

A path forward for growers
The day prioritized open conversation among growers who are facing similar energy and climate pressures and are looking for solutions that reinforce production resilience without compromising yield. "We're looking to move away from carbon-based energy, and switch to other forms. My goal is to run my greenhouse as ecologically as possible, and that means finding new renewable energy technologies like Voltiris", remarked Philippe Magnin, a 6-ha tomato and cucumber grower from the Geneva area.

© Voltiris

As energy markets and climate conditions become increasingly unpredictable, greenhouse growers need stability they can rely on. The Meier Gemüse installation shows that renewable energy generation and high-value crop production can support one another in a single system.

Following the Grower Day, several participants have initiated follow-up discussions for new commercial projects, reflecting strong interest in scaling the approach.