Agrivoltaics in wine growing areas

Chaire Paysage et énergie (ENSP), 2022

To download : brochure-agrivoltaisme--envoi-mail-1.pdf (870 KiB)

The sunny wine-growing Aspre, agricultural terraces open onto the Pyrenees

1 - The Nidolères wine estate in the heart of the Aspre wine region

The Nidolères estate has been a family-run vineyard for eight generations, with 32 hectares of vineyards. It is located in the heart of the Aspre wine-growing landscape unit, which benefits from the Côtes du Roussillon Les Aspres AOC. The unit is made up of gentle reliefs crossed by several rivers flowing from the mountains. It presents a landscape of flattened vineyard terraces, whose elongated reliefs open up remarkable views of the Aspres mountainous horizon, with the well-known silhouette of the Canigou peak. The edges of the terraces shaped by the watercourses offer slight relief where most of the villages have settled, in order to be close to the rivers without being affected by the floods.

2 - The agricultural diversity offered by irrigation

Traditional bi-cultural techniques are important in the region. Until the 1960s, the landscape was marked by farms mixing vines and apricot trees or vines and cherry trees. Gradually, the yields no longer correspond to the economic models of agricultural mechanisation, which leads to the loss of these traditions. Today, a few plots of orchards can be found very occasionally, rather linearly, in these landscapes dominated by vines. They are confined to the low terraces in the riverbeds.

3 - A visible disruption of the landscape: wine crisis and urban pressure

The uprooted vines and fallow plots are visible everywhere and mark the landscape. The outskirts of villages are particularly affected by this phenomenon: the wine crisis added to urban pressure seems to lead to an increase in the number of uprooted vines at the entrances to towns. Many housing estates and business parks are being built. Recent urban extensions often extend beyond the original built-up area: they are scattered along the roads, with no clear urban planning logic. They weaken the centres and devalue the entrances to the villages. There is talk today of a regional but also a global wine crisis, due to various pressures on the vines caused by global warming. The vines suffer from the heat in summer and the lack of shade and humidity. Traditionally, the vines were protected by trellises on the sunset side, and the vines then shaded each other because of the short distance of about 80 cm between the rows. The change from manual to mechanised harvesting reduces operating costs, but the rows have to be at least 2.5 m apart, which no longer allows for self-shading. The vines then suffer from the heat, and yields drop. In addition, there are more and more frequent episodes of rain without wind, which brings diseases to the vines, such as mildew.

Agrivoltaics to perpetuate vineyard landscapes in difficulty

1 - Vines facing the test of climate change

Pierre Escudié, the current owner and operator of the Nidolères estate, has been observing the effects of global warming on his crops for 30 years. Temperatures are increasingly high in the summer, and thunderstorms occur at all times of the year. Thirty years ago, wine-making was done on a natural cycle. Today, there is a need to add yeast to find a balance between the sugar content and acidity of the grapes. The wine is getting stronger and stronger, whereas the wines of the region are traditionally softer wines. It is becoming more and more difficult to get its production certified as a PDO belonging to the Aspre wine region. In addition, the profitability is becoming less and less good.

« A plant that suffers adapts and does not produce much fruit. Pierre Escudié, farmer and owner of the Nidolères estate

It is for these reasons that the farmer is interested in the agrivoltaic model developed by Sun’Agri.

« Going back to bi-culture systems with fruit trees is not possible, because the yields are not as good; the two plants are in competition. Pierre Escudié, farmer and owner of the Nidolères estate.

2 - Innovations in renewable energy linked to agricultural issues

Since 2009, INRAE (the National Research Institute for Agriculture, Food and the Environment), Ademe and the company Sun’R (of which Sun’Agri has become a subsidiary) have been working on the Sun’Agri research programme. The project, which is financed by the French government via the « Investissement d’Avenir » programmes, has won numerous awards. This research is based on the observation that photovoltaic energy needs land to develop. At the same time, there is the issue of preserving agricultural land. Added to this are the current issues of adapting vineyards to global warming. From all these issues, the notion of agrivoltaics is emerging, which makes it possible to combine the development of renewable energy with the preservation of agricultural land, while at the same time providing a benefit to the latter.

3 - Trackers at the service of the plant

The developer designs and builds the agrivoltaic structure, controls the louvers in accordance with the agricultural priority and carries out the agronomic monitoring of the project; the farmer benefits from a dynamic agrivoltaic structure to secure his production objectives, a project company ensures the investments of the infrastructure and benefits from the income of the electricity resale. The control of the louvers is always done for the benefit of the plants, the electricity production is a secondary benefit. The current development model requires a winning bid from the Commission de régulation de l’énergie (CRE) to obtain a purchase rate for the electricity production.

4 - State calls for tenders for economic constraints linked to innovations

The State has entrusted the CRE with the task of organising calls for tenders to regulate the production of renewable energy supported by the State. The Tresserre agrivoltaic power plant benefited from the third call for tenders launched in 2014 for the construction and operation of ground-based solar power plants.

Agrivoltaics on the Nidolères wine estate, agricultural practices and landscapes in question

1 - An innovative system to improve agricultural yields

The Sun’Agri3 research programme financed by the PIA Ademe is used to finance the experiments carried out on the Nidolères site. It benefits from a special feed-in tariff, with conventional subsidies for ground-based power plants, and an additional subsidy from the Occitanie Region to cover the extra cost of deploying a first structure. The aim is to reach the cost of ground-mounted photovoltaic plants within five years. The developer proposes mobile systems with a single axis of rotation of the panels from east to west. Sun’Agri’s intraday control is carried out by means of algorithms that integrate complex plant growth models, plant water behaviour models, weather forecasting models and panel positioning optimisation software. The panel tracking system allows the panels to be tilted sufficiently to allow the maximum amount of light to be available to the crop as required, thus creating open field conditions. The control is based on the plant and not on the sun. It is not a simple cohabitation between energy production and agricultural production, but a real service provided by the panels for the plant. The system is designed to help the plant grow optimally. The advantage of the system is that it does not compete with the plant. It avoids too much evapotranspiration, maintaining humidity and shading in hot periods.

2- Agricultural plots and energy revenues

For the Tresserre vineyard project, the owner and operator of the estate made his land available. The developer Sun’R Groupe invested. For their next agrivoltaic projects, the developer Sun’Agri, a subsidiary of the Sun’R Group created in 2019, will no longer be an energy producer but a service provider for the development and management of projects. The lease for the land is for 30 years. The choice of the plot is based on the farmer’s desire to present a plot with a gentle slope, as the panels do not adapt to topographies with steep slopes. The farmer produces three grape varieties: red marcelan, white grenache and white chardonnay. Next to the 5 ha agri-voltaic plot, there is a 2 ha control area with the same alignment and grape varieties for comparison.

3 - The stages of the project and the constructed object

The project is carried out in several stages:

1 - The tillage 2 - The panel structure 3 - A new tillage 4 - The planting of vines under the structure and on the control area (the system is not suitable for already planted vines for the moment).

The structure supporting the panels is built 4 to 5 m above the ground, so that it allows agricultural machinery to move between the crops. The system is installed using steel pile technology with no impact on the soil, future dismantling is facilitated and soil pollution is minimised. The site is not very visible from the plain, but there are many views from the slopes of the Aspres massif. The landscape issue has been given very little consideration in this project. When seen from a distance, the site appears disconnected from its surroundings. Up close, the technical structures of the high panels take up an imposing place.

4 - Energy production

The electricity produced is retransmitted to the electricity grid. Nearby lines have been moved slightly to connect to the production of the agrivoltaic plot. The installed power is 2.1MW for the general installation. A transformer has been installed, with a generator and inverters. It is clear that this has not been designed with the landscape in mind, and that its installation has only been the subject of technical reflection.

5 - Issues of agricultural model and landscape

This unique project works with an agronomic model of vineyards cultivated according to PDO standards. The technological tool of louvers developed by Sun’Agri is adapted for agricultural plots ranging from 3 to 6 ha, representative of targeted agricultural sectors, i.e. viticulture, arboriculture and market gardening that need shade. The question of the agricultural model should be questioned here. We can ask ourselves how to make PDO standards evolve that are more concerned with the environment, less based on inputs and monoculture.

6 - A lack of landscape studies

For this project, there were few local protests, probably because the plot is far from housing. The Chamber of Agriculture, which has been carrying out agronomic monitoring of the project since it was commissioned, expressed doubts at the start of the process.

This was also the case with the Prefecture. « We were mainly interested in agronomic and technical issues, and we relegated aesthetic and landscape questions to the background. For our next CRE award-winning projects, we are going to go further and implement landscape integration actions. » Anne-Lise Salomé, Head of Institutional Relations at Sun’Agri The building permit for the Nidolères project was submitted solely to the town hall. The project was assessed as an agricultural project and not as an energy project. There was no landscape study for this project and this is obvious. This would have been compulsory if the file had gone through the classic state investigation procedures. Only an environmental impact study was carried out, which revealed a low impact from 1 km. However, the timeframes for requests for agricultural subsidies (1 year maximum for subsidies for the purchase of plants) and the timeframes for the impact studies required for the files examined by the prefecture (often several years) are not the same; a long-term procedure is therefore not necessarily adapted to agricultural constraints.

The future of agri-voltaics, between innovation and global ecological issues

1 - Development of the model

During the first phase of presenting agrivoltaic projects (agricultural fairs, communication campaigns, etc.), it was farmers whose crops are affected by climate change who came to meet Sun’Agri. Currently, the company operates six experimental facilities in addition to Tresserre to acquire data and feed the models. The aim, in a few years’ time, is to benefit from the control of an artificial intelligence. On the Nidolères estate, the farmer receives visits from many people interested in the agrivoltaic project with mobile panels. He also has a hostel, which is doing very well thanks to his communication about the project, and he plans to promote the model when he sells his first bottles of wine grown using agrivoltaics.

2- The future of vineyards

The Institut National de l’Origine et de la Qualité (INAO) strictly monitors wine appellations. The notion of terroir does not only include the soil, but the whole micro-climate. For the Nidolères agrivoltaic vineyard project, it is possible that it will not pass the appellation controls, as several factors (hydrology, shading, winds, etc.) will be modified. However, it now seems necessary to change winegrowing practices, which are under great pressure due to global warming.

« We need to take measures in the Mediterranean region because there is a sharp drop in yields at the moment; wine is at its lowest. Pierre Escudié, farmer and owner of the Nidolères estate.

3 - Evolution of the landscape in 2050

The Tresserre project raises many questions in terms of landscape and territorial development. Certain actors (Region, Department, etc.) are questioning the progress of agrivoltaics, particularly on wine-growing land. If this development were massive, it could lead to the transformation of landscapes that are currently considered to be little artificial into landscapes with an industrialised appearance. However, it is also possible to imagine that the transition of part of the vineyards to agri-voltaics could take place within the framework of an integrative landscape project, favouring a change in wine-growing practices that are more virtuous in terms of the environment, consume less inputs and facilitate adaptation to climate change.

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