Less irrigation water to produce the same grapes
With this interest in research, Miguel participates in WineSolar, a project that studies how generating renewable energy can help agriculture. Solar panels have been installed in a vineyard which, while producing electricity, provide shade for the vines when they need it to protect them from high temperatures.
‘We’re in Toledo, an area with extreme heat and very dry in the summer. We’ve been seeing that, due to this thermal stress, the plants freeze up in summer. They stop photosynthesising and that’s detrimental to the grapes’ ripening, the growth of the plants and their physiology’, Miguel explains. ‘Just like with people, when I’m hot and I’m out in the country, what do I do? I go under a tree that gives me shade. Well, here we’re going to put the plants under some panels that give them shade’, he says.
The plants under the shade of the solar panels need 30 % less irrigation water to achieve the same yield as those that are in the open air
In this way, the vineyard conditions improve and there can be a greater quantity and quality of the grapes. The first results of this study have already shown that plants under the shade of solar panels need 30 % less irrigation water to achieve the same production as those in the open. What's more, their growth is more stable: for the uncovered crops, there are "weeks when the grade and size of the grape improves and weeks in which they don't, probably due to heat stress," Miguel explains, adding that this does not happen to those that are in the shade: "Growth is more linear and more continuous throughout the season."
Solar panels that move as the vines ask them to move
WineSolar was born from a partnership between four companies from different industries. Viñedos del Río Tajo, part of the González Byass group, provides the vineyard and the knowledge of vine cultivation and oenology. PVH provides the devices that control the solar panel movements. Avvale is the technological partner. And Iberdrola España is in charge of power generation and financing the initiative through the PERSEO start-up programme.
Technological innovation plays an important role in this project. The solar panels are not fixed, because if the vines were always covered, they wouldn’t grow properly: the grapes need sun to thrive. Instead of keeping still, they rotate at certain times to provide more or less shade depending on what the plants need.
To do this, an algorithm was developed that collects real-time data on the conditions of the vineyard, such as its temperature and humidity. This is used to determine how much shade is needed and then it tells the solar panel how much to tilt.
Guillermo Truán, Director of Energies at Avvale España, explains how this differs from usual solar panel operation. ‘Normally we look for them to be at an angle where the incidence of the sun is the greatest possible for most of the time to obtain more energy,’ he says. ‘In this case, we are looking to maximise the energy received from the sun, but at the same time we are looking for the panel itself to provide the right shade conditions at all times to have the right temperature and humidity for the grapes. In other words, we are changing the reasoning to improve the grape’.
‘I think it's very nice that a living thing, like a plant, is controlling solar panels. The panels are doing what we technicians think is best for the plants’.
Miguel Tejerina technical manager at Viñedos del Río Tajo
Miguel also sees this adaptation of energy generation to the needs of the vine as a very positive thing. ‘I think it’s very nice that a living being, like a plant, is controlling the solar panels. The panels are doing what we technicians think is best for the plants, so we can say that the plants control the solar panels’, he says.
Agrovoltaic energy helps the planet
WineSolar is an example of agrovoltaic energy. This consists of combining the cultivation of agricultural products and the generation of electricity on the same piece of land. A synergy that allows space to be used in a way that has a positive environmental impact.
‘This project is the paradigm of how technology can be applied to improve climate change conditions. We are reducing water use, we are reducing CO2 emissions and we are getting clean energy’.
Guillermo Truán, Director of Energies at Avvale España
This initiative contributes to the fight against the climate crisis in two ways at once. ‘First, we are installing a renewable energy source,’ Miguel points out. ‘And the plants need less irrigation; they use water more efficiently,’ he continues. Guillermo agrees: ‘This project is the paradigm of how technology can be applied to improve climate change conditions. We are reducing water use, we are reducing CO2 emissions and we are getting clean energy’.
The project was established in this vineyard located in Guadamur in the province of Toledo because of the type of viticulture it engages in – the intensive cultivation of grapes for brandy production – and because of the high solar radiation that this area of Spain receives throughout the year. In this environment, where summer temperatures are increasingly extreme and there are problems with drought, innovations that reduce irrigation needs without reducing production are particularly valuable. With the shade of the solar panels, the aim is to enable plants in this arid climate to develop in conditions more similar to those in the north of the peninsula.
Measuring how grapes ripen
For this project to succeed, a lot of information is constantly collected from the plants. Manual measurements are taken both in the vineyards covered by the panels and in a vineyard that is not covered by the panels but is very close to them, so that all other conditions are equal. In this way they can compare one result with another and draw conclusions about the impact of putting in the panels.
Miguel and his team take regular measurements of the grape conditions (temperature, humidity, growth, acidity, etc.) to analyse the differences between those under the panels and those that are not
‘From the time the plant sprouts in April until the harvest in autumn, we take regular measurements of the growth of the shoots, the speed of that growth, photosynthesis...’, says Miguel. In addition to this information, sensors placed on some of the plants automatically measure their temperature, humidity, water consumption, the diameter of their trunks.
Miguel is not alone in this work. The Polytechnical University of Madrid collaborates with the project and some of its students come to the farm to do research. This is the case of Mariana Grosso, an agricultural engineer and student of a Master's degree in Viticulture and Oenology. ‘We take grape samples and what we do is extract pH, brix - the amount of sugar - and general parameters that tell us how the ripening process is going,’ Mariana says.
0 1 2 3 , 0 1 2 3 pH
‘We take between 50 and 100 grapes, depending on the state of the crop, and we analyse them in the lab that’s right here in the vineyard,’ she explains.
Mariana Grosso Agricultural engineer and student of a master's degree in Viticulture and Oenology
Mariana is excited to be involved in an initiative like this. ‘I find participating in projects like this and being able to see from the inside the impact of how grape ripening can be modified very fulfilling. This type of research is necessary because it’s very efficient to combine a carbon capture system such as the vineyard with renewable energy generation’, she says.
Miguel agrees with how important it is to develop projects like this one. ‘Applied research in the vineyard itself, in the winery itself, is essential. Not only in farming, but in any industry’, he argues.
This is not the first time that this agricultural engineer has been involved in research. After pursuing his undergraduate in Madrid and then a master's in oenology, he worked at a wine research centre in the Priorat region of Tarragona. There he had the opportunity to experiment with different products and vine growing techniques.
He has now been in charge of the Viñedos del Río Tajo vineyards for a decade. This job allows him to be closer to his family and has helped him to participate in half a dozen R&D projects. This is what motivates him the most:
‘I really enjoy research. It’s also something out of a technical manager’s routine. It lets me read up on new topics, look for information, bibliographies.... It makes my work and my day-to-day life much more interesting’.
