Agrivoltaics, the challenge of combining solar energy and agriculture is now a reality

The National Agri-Food Technology Centre (CTAEX in Spanish) participates, in collaboration with Endesa, in a new concept known as agrivoltaics, a pioneering experience in the renewable energy sector. This project consists mainly of occupying a large part of the area destined for renewable energies and allocating it to agricultural production. This enables the land to be returned to agricultural use by planting crops and also involves local entities in the areas where the photovoltaic plants included in this project are installed.

To achieve this, we are conducting pilot tests in three photovoltaic plants in different locations, involving different crops depending on the possibilities offered by each plant taking into account factors such as location, the height of the panels, the width of the rows, types of soil, climatology, etc. Two of the plants where work is being undertaken, Valdecaballeros and Augusto, are located in Extremadura and the third, the Las Corchas plant, in Andalusia (Carmona).

Growing aromatic, medicinal and horticultural plants under solar panels

In the Valdecaballeros plant and in Las Corchas, crops of different species of aromatic and medicinal plants are being planted; these include coriander, aloe vera, rosemary and thyme, as well as polyphyletic meadow for animal feed. The crops are also used for herds of sheep who eat these same plants. The pollinators are also released to improve biodiversity in collaboration with BIOSUR, a company specialising in biological pollination.  

In the Augusto plant, in Badajoz, work is being done with high-value horticultural species, including marrows, aubergines, cauliflowers and broccoli. The first harvests have already been completed and it can now be seen that these two activities are compatible.

At all times, it has been ensured that agricultural production and the production of renewable energy do not interfere with each other with regard to the procedures and operations to be undertaken on a day-to-day basis, so they are able to adapt and coexist with the clear objective of making this project a reality. This has involved designing tests for small areas of crops that can then be escalated to large areas and to all types of photovoltaic plants. The pilot scheme occupies a surface area of over 10 hectares.

How and where to grow the plants depending on each solar plant

Apart from a selection of crops, the use of different plastic padding and anti-grass meshes is also being studied, to make it easier to maintain the tests. As for the padding, we are working with biodegradable material, white padding and black padding, studying the suitability of each of the types in different locations within the same plant, such as for example, under panels to the east, west or in the centre of the rows, to find out whether the hours under sunlight or in shade have any influence on how crops grow, depending on the orientation of the panels.

Work is also being done on the remote monitoring of the tests by installing different types of probes to measure different parameters such as temperature, ambient humidity, soil moisture, rainfall and leaf moisture, etc. to adapt the tests to Agriculture 4.0, the present and future of agricultural production. 

A pioneering project: How energy generation and agriculture can coexist

For CTAEX, as a Technology Centre, it is a key project, since sustainability, biodiversity and the establishment of synergies are just some of the centre's strategic lines. It is also a very demanding experience which has been a great challenge for the technical team conducting the tests and for entities such as Plantaroma, which is collaborating with CTAEX in the planting of crops in Las Corchas.

The work is not without its difficulties as it is something that has been completely unknown until now and involves adapting the routine procedures and operations for each photovoltaic plant. Because one of the objectives is for there to be minimum interference between the energy and agricultural activities so they can coexist suitably which will ensure this can develop from a pilot scheme to a large scale experience and enable agrivoltaics to guarantee sustainability and coexistence between the two sectors in the future.

To achieve this, it has been necessary to study, for each case, the type of agricultural machinery to be used depending on the width of rows between panels, the height of the panels, management of crops during their growth cycle and adapting them to the area and the particularities of the plants.

For those working on the project on a daily basis, it has been really gratifying to see the crops growing between the solar panels and to get the first crops from the interior of a photovoltaic plant. This has helped us to feel like true pioneers thanks to this initiative and the collaboration of Endesa.

It has been an enriching experience for all the parties involved, with the synergies established between different sectors that are destined to coexist in the very near future, according to the results that are being obtained and the conclusions that are being drawn from this agrivoltaics project.