WO2021198626A1

WO2021198626A1 - Combined production unit for agricultural products and electricity and method for optimising a production unit for agricultural products

Info

Publication number: WO2021198626A1
Application number: PCT/FR2021/050590
Authority: WO
Inventors: Ophélia Emeline Amandine SIPAN; Louis Bernard Claude Maurice
Original assignee: Groupe Okwind
Priority date: 2020-04-02
Filing date: 2021-04-02
Publication date: 2021-10-07
Also published as: FR3108827A1; FR3108827B1; EP4125328A1; EP4125329A1; WO2021198627A1

Abstract

The invention relates to a combined production unit (1, 1') for agricultural products and electricity, starting from an open-field agroforestry plot (2, 2'), the production unit (1, 1') comprising an agricultural production system (3, 3') for plant or animal material which is installed on the plot (2, 2'), the agricultural production system (3, 3') being associated with trees (4, 4') which are planted on the agroforestry plot (2, 2'), the production unit (1, 1') also comprising a system (5, 5') for converting solar energy into electrical energy, which is also installed on the plot (2, 2'). Combined production of agricultural products and electricity

Description

COMBINED PRODUCTION UNIT OF AGRICULTURAL PRODUCTS AND ELECTRICITY AND PROCESS FOR OPTIMIZING A PRODUCTION UNIT

OF AGRICULTURAL PRODUCTS

TECHNICAL AREA

The present invention relates to the general technical field of agriculture as well as that of electricity production from solar energy.

The present invention relates more particularly to a combined production unit for agricultural products and electricity, as well as to a method for optimizing a production unit for agricultural products.

PRIOR TECHNIQUE

So-called “agrivoltaic” systems are known which make it possible to cultivate plants while allowing the production of electricity by means of photovoltaic panels arranged above the crops in question to shade them.

These known agrivoltaic systems, if they are generally satisfactory, can nevertheless be optimized.

In particular, the known systems use relatively complex and bulky shade structures, which produce a significant impact on the landscape, which can in many situations represent a significant drawback.

Next, the design of known agrivoltaic systems aims above all to optimize crops by shading them, but not to optimize the process of electricity production as such.

In addition, if the known agrivoltaic systems make it possible, through the shade provided, to minimize evaporation at soil level, the intrinsic characteristics (fertility by example) of the latter are not improved, nor is the soil effectively protected against harmful natural phenomena such as erosion.

Likewise, known agrivoltaic systems do not necessarily have a significant impact on water quality either, and in particular do not allow phytosanitary treatments to be drastically reduced.

In addition, known agrivoltaic installations are not necessarily optimal in terms of carbon dioxide storage. More generally, the positive impact on biodiversity and the climate of known agrivoltaic systems is relatively measured.

Finally, the aforementioned agrivoltaic systems are exclusively dedicated to plant crops, to the exclusion of other agricultural productions.

DISCLOSURE OF THE INVENTION

The objects assigned to the invention therefore aim to remedy the various drawbacks listed above and to propose a new unit for the combined production of agricultural products and electricity, which has a versatile character as well as an optimal carbon footprint, and whose This design makes it possible in particular to optimize agricultural production but also the production of electrical energy, while limiting the use of inputs, preserving the quality of surrounding waterways, limiting soil erosion and improving their fertility.

Another object of the invention aims to provide a new unit for the combined production of agricultural products and electricity, the design of which makes it possible to maximize electricity production.

Another object of the invention aims to provide a new unit for the combined production of agricultural products and electricity which blends harmoniously into the landscape while facilitating mechanized agricultural work. Another object of the invention aims to provide a new unit for the combined production of agricultural products and electricity which allows increased production of biomass while promoting biodiversity.

Another object of the invention is to provide a new unit for the combined production of agricultural products and electricity which allows the generation of optimum shade for agricultural production.

Another object of the invention aims to provide a new unit for the combined production of agricultural products and electricity, the design of which makes it possible to obtain excellent performance in terms of electricity production while preserving the mechanical components of the machine. power generation equipment.

Another object of the invention aims to provide a new unit for the combined production of agricultural products and electricity that is easy and quick to implement.

Another object of the invention aims to provide a new unit for the combined production of agricultural products and electricity, the design of which makes it possible to optimize, in a dynamic and evolving manner over time, both agricultural production and electricity production. .

Another object of the invention aims to provide a new unit for the combined production of agricultural products and electricity which is based on a universal design capable of adapting to different types of agricultural production, and in particular to the production of material. plant or animal material production.

Another object of the invention aims to provide a new unit for the combined production of agricultural products and electricity which makes it possible to optimize a plant agricultural production activity, while preserving and improving the pedological and microbiological characteristics of the soils, by promoting less use of inputs and protecting crops against climatic hazards. Another object of the invention aims to provide a new unit for the combined production of agricultural products and electricity which makes it possible to optimize a breeding activity, in particular ensuring better physical and mental comfort for the animals, minimum consumption. exogenous foods and less use of pharmaceutical treatments.

Another object of the invention aims to provide a new method for optimizing a production unit for agricultural products which is particularly simple, fast, efficient and respectful of the environment.

The objects assigned to the invention are achieved by means of a combined production unit of agricultural products and electricity, from an agroforestry plot in the open ground, said production unit comprising an agricultural production system of plant or animal material implanted on said plot, said agricultural production system being associated with trees planted on said agroforestry plot, said production unit also comprising a system for converting solar energy into electrical energy also located on said agroforestry plot, said conversion system comprising a plurality of photovoltaic devices located in line and at a distance from each other on said plot, so as to form one or more row (s).

The objects assigned to the invention are also achieved by means of a process for optimizing a production unit of agricultural products from an agroforestry plot in open ground, said production unit comprising a production system agricultural plant or animal material implanted on said plot, said agricultural production system being associated with trees planted on said agroforestry plot, in which a system for converting solar energy into electrical energy is also installed on said agroforestry plot, said conversion system comprising a plurality of photovoltaic devices located in line and at a distance from each other on said plot, so as to form one or more row (s). SUMMARY DESCRIPTION OF THE DRAWINGS

Other features and advantages of the invention will become apparent and will emerge in more detail on reading the description given below, with reference to the appended drawings, given solely by way of illustrative and non-limiting examples, in which: Figure 1 illustrates, schematically in top view, an example of a production unit according to the invention, which implements an agricultural production system of plant material constituted in this case by a field of field crops .

- The figure illustrates, in a schematic sectional view, a detail of the production unit of Figure 1. - Figure 3 illustrates, schematically in top view, another example of a production unit according to l 'invention, which implements an agricultural production system of animal material, which in this case includes a poultry breeding course.

BEST WAY TO MAKE THE INVENTION

The invention relates to a unit 1, T for the combined production of agricultural products and electricity, from an agroforestry plot 2, 2 'in open ground. The plot 2, 2 thus forms a portion of land which is part of the soil itself, and is therefore not confined by any container. This means in particular that the plot 2, 2 'is not above ground, unlike, for example, a surface of land which could cover the roof of a building. Unit 1, T makes it possible to produce both agricultural products and more precisely initial or primary agricultural products, that is to say unprocessed, and electricity (electrical energy). More precisely, said production unit 1, T comprises a system 3 for the agricultural production of plant material or a system 3 'for the agricultural production of animal material installed on said plot 2, 2'. In the case of the example of Figures 1 and 2, the agricultural production system is a production system 3 agricultural production of plant material, while in the case of the example of FIG. 3 the agricultural production system is a 3 'agricultural production system of animal material.

As mentioned previously, plot 2, 2 'is an agroforestry plot, that is to say an agricultural plot that combines trees 4, 4' on the one hand, and crops and / or animals on the other. Thus, the agricultural production system 3, 3 'is associated with trees 4, 4' planted on said agroforestry plot 2, 2 ', at the edge and / or at the heart of the latter. The term “tree” advantageously designates here any branched woody plant, for example with a trunk lined with branches, of variable size and height. Trees 4, 4 'of plot 2, 2' can thus include shrubs, fruit trees, tall trees, stem trees, trees or shrubs with erect, shrubby, arborescent or bushy growth, deciduous trees, conifers or conifers, this list not being exhaustive.

The agroforestry plot 2, 2 ′ can thus be of different natures, and for example constitute an agrosilvicultural system, or else a sylvopastoral system, or even a pre-plantation, this list not being of course exhaustive either.

In addition, according to the invention, the production unit 1, 1 'also comprises a system 5, 5' for converting solar energy into electrical energy, said conversion system 5, 5 'also being located on said device. plot 2, 2 'agroforestry, in association with the system 3, 3' of agricultural production and trees 4, 4 '.

Thanks to this original combination, which combines agroforestry technique and agrivoltaism by associating agricultural production, trees and a system for converting solar energy into electrical energy, multiple and synergistic benefits can be obtained.

A first advantage lies in the diversification of the production of plot 2, 2 ’, which in addition to agricultural production (agricultural plant materials and / or agricultural animal materials) also ensures:

- electricity production (which may or may not be reused by the operation), - as well as a production of sylvicultural plant material, useful for example to produce timber, or biomass usable for example for soil fertilization (for example in the form of fragmented raméal wood or BRF), or else of thermal energy (wood energy), or to produce litter for farm animals.

The products, services and operating income are thus diversified and secure.

Thanks to the agroforestry nature of plot 2, 2 ', the system 3, 3' of agricultural production established on plot 2, 2 'requires the use of fewer inputs. Indeed, soil fertility is improved thanks to the biomass of the trees (returned to the soil via the falling leaves and the decomposition of the roots), which is rich in lignin and helps to form a particularly stable and fertile humus. The quality of the water is also improved, with a better structuring of the soil thanks to the root systems of the trees which not only facilitate the biological activity of the soil, improve the infiltration of runoff and limit evaporation from the soil, but also allow reduce the pollution of groundwater and watercourses by limiting the leaching of nitrates. The better structuring of the soil also makes it possible to fight against erosion.

The agroforestry nature of plot 2, 2 'also makes it possible to sequester carbon, which thus makes it possible to act favorably on the climate. This beneficial effect is accentuated by the presence of the system 5, 5 'for converting solar energy into electrical energy, which leads to an advantageous carbon footprint.

The presence of trees 4, 4 'also makes it possible, in the case where the agricultural production system implemented is a system 3 for agricultural production of plant material, to reduce the phytosanitary treatments. Trees 4 indeed contribute to an improvement in biodiversity, by structuring habitats which shelter flora and fauna useful for agricultural production. The risk of lodging is also reduced because the trees 4, in particular when they are organized in hedges, protect the crops from the wind. In general, the plants undergo less stress so that agricultural productivity is improved by the presence of trees 4 and the forest character of the plot. Advantageously, said trees 4, 4 'are not trees intended for food. In particular, said trees 4, 4 ', whatever their location, do not form part as such of the agricultural production system 3, 3', and are therefore not suitable and intended to produce an edible food and / or a raw material intended for the agrifood industry (unlike the system 3, 3 'of agricultural production).

Advantageously, said system 3, 3 "of agricultural production is an agricultural production system of plant material comprising plants, said trees 4, 4" being distinct from said plants and of a variety different from that of said plants.

According to a variant, said system 3, 3 'of agricultural production comprises one or more zones each delimited by a respective perimeter within which the agricultural production is carried out, and some of said trees 4, 4' are planted inside of said perimeter while others are planted outside said perimeter and / or on said perimeter.

When the agricultural production system is a 3 'system of agricultural production of animal material, for example a livestock system, the beneficial effects of the agroforestry nature of plot 2' observed are in particular the following:

- climatic protection (more comfort and less stress for the animals, which therefore produce fewer toxins, which improves the finished product);

- less exogenous food consumed (part of the needs are covered by inputs from trees, especially when they are organized in hedges, and / or by better exploration of the plot by animals);

- reduced pharmaceutical treatment requirements (improved animal health);

- and better nutritional value of the finished product.

As for the presence of the system 5, 5 'for converting solar energy into electrical energy on the plot 2, 2', it makes it possible to generate shade, produced by the components (and in particular the photovoltaic panels) of the system. 5, 5 ' conversion of solar energy into electrical energy, which helps protect soils and animals while generating possible income from the sale of the electricity thus produced. The productivity of the agricultural land making up the plot 2, 2 'is thus improved by the joint production of food products and energy.

The association of the shafts 4, 4 'and of the system 5, 5' for converting solar energy into electrical energy also makes it possible to obtain remarkable synergistic effects, and in particular the beneficial effects described below.

First of all, the presence of trees 4, 4 ', in particular when they contribute to forming or form peripheral hedges, increases the "roughness" of the site of the plot 2, 2', which makes it possible to protect the system. 5, 5 'of converting solar energy into electrical energy from climatic excesses, in particular wind. In particular, when trackers (or solar trackers) are implemented by the 5, 5 'conversion system, the latter will be less often put in the safety position (flattening), so that the production of electricity will be maximized and tracker components will experience less mechanical fatigue.

Another interesting synergistic effect resides in the fact that the production performance of the system 5, 5 ′ for converting solar energy into electrical energy is improved by the “crop + trees” microclimate (when a system 3 for agricultural production of material plant is implemented) or the “meadow + trees” micro-climate (when a 3 'system of agricultural production of animal matter is implemented). In fact, heat generally affects the performance of photovoltaic cells. The microclimate created by the vegetation, and in particular by the trees 4, 4 'planted on the agroforestry plot 2, 2', leads, via the phenomenon of evapotranspiration, to a local drop in temperature which thus limits the heating of the photovoltaic cells and improves the efficiency of the 5.5 'conversion system.

In addition, the association of a silvicultural development and a system for converting solar energy into electrical energy on the same agroforestry plot allows to benefit from a dynamic synergy over time. Indeed, during the first years following the creation of unit 1, T, while trees 4, 4 'may still be young people who produce little or no shade, the system 5, 5 ′ for converting solar energy into electrical energy makes it possible to immediately provide sufficient shade in particular to promote the development of trees and limit local drying out of the soil. The immediately available shade area thanks to the installation of the conversion system 5, 5 'on the plot 2, 2' also allows, when the agricultural production system concerned is a 3 'system of agricultural production of animal matter (putting for example a poultry breeding course), to provide comfort and safety to the animals, while waiting for the trees to grow sufficiently, while protecting them from predators and the sun. Subsequently, the two entities (system 5, 5 'for converting solar energy into electrical energy on the one hand and trees 4, 4' on the other hand) complement each other.

Furthermore, in order not to interfere with the operation of the system 5, 5 ′ for converting solar energy into electrical energy, in particular when this system uses photovoltaic modules whose spatial orientation varies automatically to follow the sun (device for "tracker" type), the trees 4, 4 'located in the vicinity of the system 5, 5' for converting solar energy into electrical energy are pruned to limit their height to a value (for example of the order of 2 m) compatible with the race of the trackers, which limits the potentially negative effect of the shade usually observed in the traditional agroforestry systems where the subjects are much larger.

The association, on the same plot, of a system 3, 3 'of agricultural production of plant or animal matter, of a system of production of sylvicultural plant material and of a solar energy production system therefore allows, as explained above, to generate particularly interesting synergies for the operation itself, the environment and the climate.

According to the invention, the conversion system 5, 5 'comprises a plurality of photovoltaic devices 50, 50'. Advantageously, one or more of said photovoltaic devices 50, 50 'each comprise a photovoltaic module 51, 51'. Preferably, each photovoltaic device 50, 50 'comprises a module respective photovoltaic 51, 51 ′, formed for example by a photovoltaic panel (which can itself be formed by the combination of several elementary panels), and whose spatial orientation varies, according to a particular variant, automatically according to a or more command parameters. The control parameter (s) in question advantageously include astronomical and / or meteorological parameters, so that each photovoltaic module can advantageously follow the course of the sun in order to optimize the production of electricity, can also adopt a position of rest at night (flattening) and finally be able to adopt a safety position in the event of a violent meteorological phenomenon (for example flattening in the event of too strong wind or vertically in the event of hail). The use of photovoltaic modules 51, 51 'with variable spatial orientation also proves to be particularly advantageous as regards the shadow provided by each module 51, 51' on the plot 2, 2 '. Thanks to the mobility of the modules 51, 51 ', the shade is in fact distributed over the day and the seasons, which limits its potential negative impact on the agricultural production of the plot 2, 2'. Preferably, each photovoltaic panel forming a module 51, 51 'has an area which is between approximately 50 and 200 m ² , preferably between 80 and 150 m ² , such areas having an excellent compromise between the production of electrical energy. and the shading induced on the plot 2, 2 '.

Such photovoltaic modules 51, 51 ′ with automatically variable spatial orientation are known as such, and are commonly called “trackers”, “solar trackers” or even “solar trackers”. Solar trackers generally use a supporting structure which makes it possible to gradually vary the spatial orientation of photovoltaic panels mounted on the supporting structure, according to the heliostat principle, in order to increase their productivity. This orientation is advantageously operated according to two axes of rotation, namely a vertical axis and a horizontal axis, which allows the photovoltaic panels forming the photovoltaic module 51, 51 'to automatically follow the course of the sun by adjusting continuously or at regular time intervals. elevation and azimuth in a controlled manner, in response to changing control parameters. Advantageously, each photovoltaic device 50, 50 'comprises a respective mast 52 on which the respective photovoltaic module 51, 51' is mounted. Thanks to this characteristic, the footprint of the conversion system 5, 5 'is very limited, which facilitates agricultural work on the plot 2, 2'. Advantageously, each mast 52 is high enough to free a passage under each photovoltaic module 51, 51 'in order in particular to allow the passage of agricultural vehicles 10, of the tractor type or the like. Each mast 52 has for example a height of between 4 and 10 m, the photovoltaic module 51, 51 'being fixed to the top of the corresponding mast 52, by means of a mechanical connection allowing pivoting along a vertical axis and along a horizontal axis . This height positioning of the photovoltaic module contributes to the good ventilation of the latter, which makes it possible to limit the effects of untimely heating which could harm the efficiency of the photovoltaic module 51.

Advantageously, each photovoltaic module 51, 51 ’comprises a panel with a face face and an opposite back face, said face face and back face being both provided with photovoltaic cells. Thanks to this two-sided arrangement, each photovoltaic module 51, 51 ′ is able not only to directly capture the light coming from the sun by means of its front face, but also, thanks to its reverse face, to capture reflected light and to diffused light to help in the production of electricity, which makes it possible to produce 10 to 25% more energy compared to a single-sided arrangement.

The embodiment corresponding to Figures 1 and 2 will now be described in more detail. In this exemplary embodiment, the agricultural production system of unit 1 is a system 3 for agricultural production of plant material. More precisely, said system 3 for the agricultural production of plant material advantageously comprises a field of field crops, for example cereals, oilseeds, protein crops and / or fodder crop plants, of the natural or artificial grassland type. Advantageously, the system 3 for the agricultural production of plant material, formed for example by a field 30 of large-crop plants, is implanted on the surface of the plot 2 available outside the surfaces occupied by said trees 4 and the conversion system 5. solar energy into electrical energy. According to the invention and as illustrated in Figures 1 and 2, the photovoltaic devices 50, 50 'are located in line and at a distance from each other on said plot 2, so as to form one or more rows 6, 7, 8, which rows 6, 7, 8 are for example, as illustrated in the figures, identical, substantially rectilinear, parallel and distant from each other (see FIG. 1). Thus, the photovoltaic devices 50, 50 'of the same row are preferably located at a distance from each other, which allows better landscape integration of the latter while facilitating access to the system 3, 3' of agricultural production which very often is found around (or even partly below) the photovoltaic devices 50, 50 '. Furthermore, the photovoltaic devices 50, 50 'of the same row are advantageously substantially aligned in a respective direction (an approximate straight line), said direction preferably being substantially horizontal.

Advantageously, said trees 4 comprise a first plurality of trees 40 planted in a row to form, or help to form, a first hedge 9 which occupies the inter-photovoltaic device spaces 50 in each row 6, 7, 8 (of which there are of three in the example shown). The first hedge 9 is thus composed of substantially rectilinear elementary sections which extend longitudinally, in each row 6, 7, 8, between each photovoltaic device 50, that is to say in this case between each mast 52. By example, said first hedge 9 has a maximum height H less than or equal to approximately 2 m, and preferably of the order of 1.5 to 2 m, so as to be able to come as close as possible to the photovoltaic devices 50, and more precisely respective masts 52 of the latter, without hindering the course of the photovoltaic modules 51 with variable spatial orientation, while promoting the production of biomass and the presence of biodiversity useful for the productivity of the plot 2.

Advantageously, said first hedge 9 comprises alternately trunks 90 to produce biomass and plants with bushy growth 91 to promote biodiversity. The trognes can even be qualified as mini-trognes to take into account the height constraints linked to the vicinity of the trackers. The "mini-trogne" pruning keeps the trees 4 in the phase of continuous growth, which thus makes it possible to continue to store carbon throughout the life of the tree (in the absence of in turn, trees store carbon during their growth and stop storing when they reach maturity). In the same row, the edges 90 are for example mutually spaced by a distance D3 of between 0.5 m and 5 m, for example of the order of 2 m on average. Advantageously, the cores 90 are implanted at a density of approximately 4 cores / m ² . The alternation of trognes 90 and species favoring biodiversity 91 makes it possible both to produce, thanks to the trognes, wood (for example firewood) and / or fodder, while providing, thanks to the plants at port bushy 91 interposed between the trunks 90, flowers, fruits and refuges for animals, thus promoting biodiversity and therefore indirectly the productivity of the plot 2. The trunks of trees 4 is particularly advantageous. It makes it possible to obtain tree heights compatible with the presence in the immediate vicinity of the photovoltaic devices 50, the respective photovoltaic module 51 of which is placed at an altitude greater than the height of the first hedge 9, thanks to the mounting on a mast 52. , while optimizing the production of forest plant matter.

Advantageously, said rows 6, 7, 8 are spaced from each other by a substantially constant distance D0, for example at least equal to 10 m, preferably at least equal to 30 m, and even more preferably from the order on average of 40 m, in order to spare between rows 6, 7, 8, in the working direction of plot 2, sufficient passages to allow the work of the farmer, including of course with mechanized means ( tractor 10 or other). The distance D0 is advantageously measured between two alignments of trackers, which leaves, when the inter-row distance D0 is equal to 40 m, a working width D1 for example of about 36 m, sufficient to allow agricultural machinery to pass 10 .

Advantageously, within each row 6, 7, 8, the photovoltaic devices 50 are spaced from each other by a distance D2 (measured for example between each mast 52) which is substantially constant, for example at least equal to 10 m, of preferably at least equal to 20 m, even more preferably of the order of 35 m on average. Such an arrangement allows a good compromise between the production of electrical energy and the possible harmful effects of the shade generated by the photovoltaic panels on the crops. Advantageously, said trees 4 comprise a second plurality of trees 41 planted on the periphery of the plot 2 to form, or help to form, a second peripheral hedge 11, of the windbreak type, preferably continuous, and which preferably surrounds said plot 2. Thanks to the presence of this second hedge 11, the risk of lodging and of deterioration or of frequent securing of the photovoltaic devices 50 is minimized, which makes it possible to optimize both agricultural production and the production of electrical energy, while also allowing additional biomass production.

Advantageously, the system 5 for converting solar energy into electrical energy comprises electrical cables connected to each photovoltaic device 50 to transport the electrical energy produced by the latter. Said cables are buried in the ground of plot 2, and advantageously run along each row 6, 7, 8 according to one or more paths which extend substantially parallel to said rows

6, 7, 8, at a distance of at least 1 m, and preferably about 2 m, from said rows 6,

7, 8. In this advantageous case of figure, the cables carrying the electrical energy produced by the photovoltaic devices 50 are buried in the ground of the plot 2 to a depth preferably at least equal to 30 cm and less than 1, 5 m, preferably at least equal to 40 cm and less than 1 m, even more preferably equal to on average about 60 cm. Particularly preferably, the cables run along each row 6, 7, 8 along rectilinear paths which extend approximately 2 m from the line of trackers advantageously forming the photovoltaic devices 50, which in this case allows burying at 60 cm deep, easy and quick to make. A cable duct could be considered under the first hedge 9, but in this case it would be necessary to provide for a burial depth of at least 2.5 m.

In the preferred embodiment illustrated in Figures 1 and 2, unit 1 makes it possible to capture and use up to five times more solar energy than a simple large-scale system, with storage which can go up to to about 7.32 t of CC eq> 2 per hectare and per year, or even up to about 9.15 t of CO2 eq per hectare and per year if complementary agro-ecological practices (for example sowing direct and plant cover in inter-culture) are implemented. Thanks to the implementation of photovoltaic modules whose spatial orientation varies automatically, preferably to follow the course of the sun, the shadow produced by the system 5 for converting solar energy into electrical energy has no impact. negative on crop yield, due to the distribution of shade over the day and the seasons. By maintaining the first hedge 9 at a height preferably not exceeding 2 m, so as not to hinder the course of the trackers, an additional beneficial effect is obtained of limiting the impact of the shadow produced by the hedge, especially compared to a classic agroforestry system where the subjects are usually much larger. As mentioned previously, the microclimate created by the vegetation (field crops and trees 4) leads, via evapotranspiration, to a local drop in temperature which limits the heating of the photovoltaic cells, which promotes their optimal functioning. The presence of trackers also makes it possible, in the first years of the creation of Unit 1, to compensate for the small size of the trees, in particular by providing sufficient shade which will promote tree development and limit local drying out of the soil. Subsequently, the trackers 50 and the shafts 4 complement each other as mentioned above. Finally, the electricity produced by the system 5 for converting solar energy into electrical energy can be used locally, for example for pumping water, for irrigation, or even for misting, for example.

The invention is of course not limited to a production unit implementing an agricultural production system of plant material as in the example of Figures 1 and 2. It is in fact also possible that the agricultural production system of the production unit according to the invention is a system 3 ′ for agricultural production of animal material as illustrated in FIG. 3.

In the particular example of FIG. 3, the system 3 ′ for the agricultural production of animal material advantageously includes a poultry rearing course, located on the agroforestry plot 2 ′. The system 3 'of agricultural production of animal material comprises in this case a henhouse 12 constituted in this case by a building arranged on the plot 2' and which is provided with hatches allowing the exit of the poultry (indicated by the arrows 12A) to outside, in the open, on plot 2 '. In this particular embodiment, the photovoltaic devices 50 'are distributed in a substantially homogeneous manner over the course, by being implanted for example at a distance of between 20 and 40 meters, preferably of about 35 m, from each other of all parts (north-south axis and east-west axis).

Advantageously, the trees 4 'planted on the plot 2' form, or help to form, at least:

- windbreak hedges 13,14, preferably with a height of at least 4 m, advantageously located perpendicular to the direction of the prevailing winds blowing on the plot 2 ',

- and / or a silvicultural development 15, including for example tall trees which will participate in the landscape integration of the whole system.

Preferably, said trees 4 'form, or help to form, low hedges 16 and / or small groves 17, with a height of for example between 1 and 3 m (for example low hedges 16 have a height of between 2 and 3 m while the small groves 17 are about 1.5 m high), which act as connecting elements between the photovoltaic devices 50 'between them, and / or between the photovoltaic devices 50' and the silvicultural development 15 .

The plot 2 'is thus advantageously provided with elements distant from each other, which act as an “anchor point” for the animals which can find there shade, shelter against predators and / or food. (berries, fruits, insects ...). These elements are formed by the photovoltaic devices 50 'scattered over the course established on the plot 2', as well as by the trees 4 'implanted on the plot 2' and which appear in the form of isolated subjects and / or low hedges. 16 and / or small groves 17 for example. The elements in question are advantageously located so as to be distant from at least one other element by a distance which does not exceed 25 m (maximum distance that a poultry can cross in practice between two shelters, in the open) . Ideally, the distance in question will not exceed 15 m to facilitate the exploration of the entire course by the animals. The use of trackers to constitute the photovoltaic devices 50 ′ makes it possible to provide a large area of shade available from the installation, while the trees 4 ′ are still small and provide little or no shade. Then the 4 'trees will grow and contribute in their turn to providing sufficient shade and shelter to poultry, while optimizing electricity production thanks to the creation by the vegetation of a “meadow + trees” microclimate, by evapotranspiration, which causes a local drop in temperature limiting the heating of the photovoltaic cells. Of course, part of the electricity generated at the level of the plot 2 'can be used to supply livestock equipment.

The invention ultimately makes it possible to optimize the use of solar radiation, by favoring the combined and synergistic implementation of different biological mechanisms (photosynthesis, etc.) and techniques (photovoltaic conversion) with efficient CO2 sequestration.

Regarding this last point, some operations can thanks to the invention go from a negative carbon storage balance to a positive one (the exploitation stores more carbon than it produces).

For example, we can estimate in the first approach that for a plot of the type of that illustrated in figure 1, which associates:

- a field of arable crops 3,

- solar trackers 50 implementing two-sided panels, of the 315 Wp twin-glass monocrystalline type, each tracker having the characteristics set out in Table 1 below,

- a peripheral hedge 11 extending over 400 linear meters,

- and mini-trognes 90 arranged in a hedge between the trackers, then a duration of an order of magnitude of 7.5 years only would be required to offset the CO2 emissions generated by the installation of the trackers (at the rate of 6 trackers / hectare), based on a productive capacity of 2000 kWh / kWp and storage by the agroforestry system of around 7.32 t C02eq / ha / year. Table 1

The invention also allows dynamic deployment which quickly leads to significant performance, while developing the territory in a simple, rapid, efficient and harmonious manner.

Finally, the invention can easily be implemented using already existing production units for agricultural products. The invention also relates, moreover, as such to a method for optimizing a production unit for agricultural products from an agroforestry plot 2, 2 'in open ground, the production unit comprising a system 3. , 3 'of agricultural production of plant or animal matter implanted on said plot

2, 2 '. The agricultural production system 3, 3 'is thus associated with trees 4, 4' planted on said agroforestry plot 2, 2 '. According to the method of the invention, a system 5, 5 'for converting solar energy into electrical energy is also installed on said agroforestry plot 2, 2', in order to obtain the various beneficial and synergistic effects mentioned in what precedes. According to the method of the invention, said conversion system 5, 5 'comprises a plurality of photovoltaic devices 50, 50' implanted in line and at a distance from each other on said plot 2, so as to form one or more rows ( s) 6, 7, 8. The method thus makes it possible to obtain a combined production unit 1, T according to the invention, in accordance with the preceding description, which description is applicable, mutatis mutandis, to the method of the invention and vice versa.

POSSIBILITY OF INDUSTRIAL APPLICATION The production unit and the optimization process of the invention make it possible to develop agricultural areas in a particularly advantageous manner by improving the overall productivity of the latter, while diversifying the sources of income for farmers (including Breeders).

Claims

1. Unit (1, 1 ') of combined production of agricultural products and electricity, from an agroforestry plot (2, 2') in open ground, said unit (1, T) of production comprising a system ( 3, 3 ') of agricultural production of plant or animal matter implanted on said plot (2, 2'), said system (3, 3 ') of agricultural production being associated with trees (4, 4') planted on said plot (2, 2 ') agroforestry, said production unit (1, T) also comprising a system (5, 5') for converting solar energy into electrical energy, also located on said agroforestry plot (2, 2 '), said conversion system (5, 5 ') comprising a plurality of photovoltaic devices (50, 50') located in line and at a distance from each other on said plot (2), so as to form one or more row (s) (6, 7, 8).

2. Production unit (1, T) according to the preceding claim characterized in that each photovoltaic device (s) (50, 50 ') comprises a respective photovoltaic module (51, 5T) whose spatial orientation varies automatically. depending on one or more command parameters.

3. Production unit (1, T) according to the preceding claim, characterized in that each photovoltaic device (50, 50 ’) comprises a respective mast (52) on which is mounted the respective photovoltaic module (51, 5 T).

4. Production unit (1, T) according to one of the preceding claims, characterized in that each photovoltaic module (51, 5T) comprises a panel with a face face and an opposite back face, said face faces and back being all two fitted with photovoltaic cells.

5. Production unit (1, T) according to one of the preceding claims, characterized in that said trees (4, 4 ’) are not trees intended for food.

6. Production unit (1, T) according to one of the preceding claims, characterized in that said system (3, 3 ') of agricultural production is a production system agricultural plant material comprising plants, said trees (4, 4 ') being distinct from said plants and of a variety different from that of said plants.

7. Production unit (1) according to one of the preceding claims, characterized in that said system (3, 3 ') of agricultural production comprises one or more zones each delimited by a respective perimeter within which agricultural production is carried out. , and in that some of said trees (4, 4 ') are planted inside said perimeter while others are planted outside said perimeter and / or on said perimeter.

8. Production unit (1) according to the preceding claim characterized in that said trees (4) comprise a first plurality of trees (40) planted in line (s) to form, or help to form, a first hedge (9 ) which occupies the inter-photovoltaic device spaces (50) in each row (6, 7, 8).

9. Production unit (1) according to the preceding claim characterized in that said first hedge (9) comprises alternately stems (90) to produce biomass and plants with bushy growth (91) to promote biodiversity.

10. Production unit (1) according to claim 8 or 9 characterized in that said first hedge (9) has a maximum height less than or equal to about 2 m.

11. Unit (1) of production according to one of the preceding claims, characterized in that said rows (6, 7, 8) are spaced from each other by a distance (D0) substantially constant at least equal to 10 m , preferably at least equal to 30 m, even more preferably of the order of 40 m on average.

12. Unit (1) of production according to one of the preceding claims, characterized in that within each row (6, 7, 8) the photovoltaic devices (50) are spaced from each other by a distance ( D2) substantially constant at least equal to 10 m, preferably at least equal to 20 m, even more preferably of the order on average of 35 m.

13. Unit (1) of production according to one of the preceding claims, characterized in that said conversion system (5) comprises electric cables connected to each photovoltaic device (50) for transporting the electric energy produced by the latter, said cables being buried in the ground of the plot (2), to a depth at least equal to 30 cm and less than 1.5 m, preferably at least equal to 40 cm and less than 1 m, even more preferably equal on average to about 60 cm, said cables running along each row (6, 7, 8) along one or more paths which extend substantially parallel to the rows (6, 7, 8), at a distance of at least less 1 m, and preferably about 2 m, of said rows (6, 7, 8).

14. Unit (1) of production according to one of the preceding claims characterized in that said trees (4) comprise a second plurality (41) of trees planted on the periphery of the plot to form, or help to form, a second Peripheral hedge (11), of windbreak type, preferably continuous, which preferably surrounds said plot (2).

15. Unit (1) of production according to one of the preceding claims characterized in that said agricultural production system is a system (3) of agricultural production of plant material which is located on the surface of said available plot outside the occupied areas. by said shafts (4) and said conversion system (5).

16. Unit (1) of production according to the preceding claim characterized in that said system (3) of agricultural production of plant material comprises a field (30) of field crops, for example cereals, oilseeds, protein crops and / or fodder crop plants, of the natural or artificial grassland type.

17. Unit (1 ') of production according to one of claims 1 to 14 characterized in that said system (3') of agricultural production is an agricultural production system of animal material, which includes a poultry rearing course .

18. Production unit (1 ') according to the preceding claim, characterized in that said photovoltaic devices (50') are distributed substantially homogeneously over said path, being located at a distance of between 20 and 40 m, preferably of about 35 m, from each other on all sides.

19. Unit (1 ’) of production according to claim 17 or 18, characterized in that said trees (4’) planted on the plot (2 ’) form, or help to form, at least:

- windbreak hedges of (13, 14) height at least equal to 4 m, located perpendicular to the direction of the prevailing winds blowing on the plot (2 ’),

- and / or a silvicultural arrangement (15), including for example tall trees.

20. Unit (1 ') of production according to the preceding claim, characterized in that said trees (4') form, or help to form, low hedges (16) and / or small groves (17), including height. between 1 and 3 m, which act as connecting elements between the photovoltaic devices (50 ') between them, and / or between the photovoltaic devices (50') and the forestry development (15).

21. Process for optimizing a production unit for agricultural products from an agroforestry plot (2, 2 ') in open ground, said production unit comprising a system (3, 3') for agricultural production of material plant or animal planted on said plot (2, 2 '), said system (3, 3') of agricultural production being associated with trees (4, 4 ') planted on said agroforestry plot (2, 2'), in which a system (5, 5 ') for converting solar energy into electrical energy is also installed on said agroforestry plot (2, 2'), said conversion system (5, 5 ') comprising a plurality of photovoltaic devices (50 , 50 ') located in line and at a distance from each other on said plot (2), so as to form one or more row (s) (6, 7, 8).