True to our motto , “Ahead of the Times Through Tradition,” we launched another milestone in our winery’s history in 2020 as part of a pilot project: what may be the world’s first multi-use agri-PV system in viticulture. As a first step, we analyzed the use of a retractable solar roof. Learn more about this initial solution we explored in the video.
In 2019 (after three years of improving the soil structure), we planted the hardy Divico grape variety, which requires virtually no plant protection. That is why it is also referred to as a Piwi variety (fungus-resistant variety). The entire plot (approx. 8,000 m²) is fenced in, and our Ouessant sheep are already grazing there. We set the top wire high enough so that the sheep can move freely back and forth underneath the vines. This was the original idea behind the year-round dual use of the plot (as pastureland and for grape production).
Although the plot is located in a wine-growing zone, it borders directly on an industrial zone, which is why our latest Agri-PV project is a perfect fit.
In the first version, we wanted to achieve multiple uses of the land by installing a so-called retractable solar roof over the vineyard plot. In recent years, the company dhp technology has developed a solution using proven Swiss cable car technology that is currently unique worldwide. You can learn how we intended to apply this approach and technology to viticulture in the animated video above.
However, the solar folding roof solution was rejected following the preliminary study. This is because, given the soil structure, the anchors would have required enormous effort to install without concrete foundations due to the calculated tensile forces (screws driven up to 8 meters into the ground). The entire system would have become far too bulky. So we explored other solutions. The solution already in use in berry crops was the focus of the second analysis. The company Insolight offers semi-transparent modules. We wanted to expand this solution with a tracking system (to ensure the solar modules’ mobility).
Agri-PV is of interest at this vineyard in that an intelligent control system could potentially help overcome certain other challenges as well:
- If the vines need more light, the angle of the panels is adjusted (tracking).
- On hot summer days, the system provides appropriate shading.
- We are investigating whether the ripening process of the early-ripening Divico variety can be delayed to achieve a more ideal harvest time (sugar and fruit ripeness).
- In this pilot project, we aim to determine how the Agri-PV system can reduce damage to the vineyard (by delaying budbreak or utilizing waste heat during frosty nights). We may even use electricity for heating during frosty nights instead of paraffin candles.
- Multi-use as a contribution to the energy transition on a plot of land that would otherwise be used “only” for vines (resource efficiency) and is ideally located.
Although all the agencies involved considered the project worthy of support, the initiative had to be abandoned. The Department of the Environment informed us that even a simple reorientation of the solar panels is considered a construction project. Since the plot is located in an S2 groundwater protection zone, the canton cannot approve the project despite everything. To do so, the legislation would have to be amended or interpreted accordingly. As a result, we had to suspend our project.
Many people also ask us why we don’t carry out the project on a different plot. Since it requires various specific conditions (proximity to transformer stations/power lines, suitable grape variety, topography), we were unfortunately unable to identify a suitable plot in our plot registry.
Our initiative sparked a debate in Switzerland and thus helped pave the way for future projects. We’re glad that other wineries have taken up the idea and are now launching projects that will hopefully have a better chance of success.
We are aware that such agri-PV systems have an aesthetic impact on the natural environment. For this reason, such solutions cannot be installed everywhere. Of course, we see great potential for “standard” agri-photovoltaics (APV) in greenhouses used for berry and fruit cultivation.
Since the plot in the valley lies directly along the cantonal highway and there are nearby industrial facilities that can also use electricity, the plot is well-suited for this purpose as well. Due to the hardy grape variety, there is also no risk of damage to the agri-PV panels from any plant protection products that might be used.
As of 2024, there are currently no large-scale agri-PV projects of this kind that incorporate multiple uses in viticulture. This is partly because, until 2023, Switzerland’s Spatial Planning Act fundamentally prohibits agri-PV. Various research and pilot projects are underway abroad. In Switzerland, Agroscope recently commissioned a fixed-mount system on a very small scale.
A collaboration agreement was signed with Agroscope to ensure that the results are widely accessible.
We’ve done our homework and are ready for the next phase. With the amendment of the Spatial Planning Ordinance (RPV) at the national level, the way is now clear for the preliminary study and the subsequent building permit application. Of course, financing is not without its challenges. However, we are convinced that such projects are worthy of support if we are to truly achieve the energy transition. We already cover our current electricity needs (theoretically) through our own production using conventional PV systems (roof and facade solutions).
Cave du Rhodan has been a member of the industry associationSwisscleantechfor years and is therefore well-connected when it comes to developing projects that will benefit future generations. This was also the case at a Swisscleantech event, where we found Birchmeier as an industry partner for a cross-winery resource efficiency project to implement what was then the world’s only electric backpack sprayer.
Learn more about all our sustainability initiatives here:
