feedbacks and assessment of agrovoltaic projects …...feedbacks and assessment of agrovoltaic...

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Feedbacks and Assessment of agrovoltaic projects on greenhouses

OFATE, 12/10/2018Alix Drezet – DREAL PACALuc Petitpain – DREAL PACA

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Summary

1. General concepts and definition of agrivoltaism

2. Feedback of some PV greenhouses projects in PACA

3. Elements for the success of a project

4. Future of the sector

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AGRIVOLTAISM :

– Mix a main agricultural production with a secondary photovoltaic production

– Agricultural production must be balanced with photovoltaic production

– In France, it mainly concerns photovoltaic greenhouses, but also other innovative systems

– The objectives are :

• to optimize the agricultural land use• to keep or increase agricultural yields• to help farmers to diversify the source

of their income


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Summary





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2007-2011Start of the first PV greenhouses

Many greenhouses known as "alibis" without any agricultural production

ADEME november 2010« too many technical and agronomic uncertainties in the medium and long term (productivity, reliability, sustainability) to promote it. »

Emergence of the PV sector in France

2007 - 2010

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More than 60% of the rooftop for photovoltaic panels ; In most cases, the inside of the greenhouse is used for storage


● Main purpose was the production of photovoltaic energy in order to benefit from advantageous subsides in areas where the cost of land is less important.

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2011 2012-2015

New support mecanisme for photovoltaic

Greenhouses with various agronomic performance

Increase in the number of greenhouses

Hard to assess the agricultural performance of projects without technical framework

2007 - 2010 2011 - 2014

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Various greenhouse design :

● Multi-chapel "cathedral" greenhouse :

Most common model currently in use in France. known as "VENLO"

● Mono chapel greenhouse with asymmetrical photovoltaic structure

They allow the shade of the panels to be shifted to non-cultivated areas. Only the upper part of the roof is covered with photovoltaic panels (a little more than 60% of the roof surface)

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These structures

● offer a large volume of air, allowing temperature differences to be tempered

● allowing crops located on the periphery of the greenhouse to benefit from significant lateral solar radiation due to the height of the greenhouse (currently 7 to 10 m).

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2012-2015: monitoring made ( by APREL) in several greenhouses has shown 3 main problems :

1. undersized ventilation systems causes climatic problems inside the greenhouse that lead to undesirable effects on agricultural production (rotting, diseases, etc.)

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An excellent dimensioning of the ventilation system is essential because :

– photovoltaic panels can prevent proper use of the ventilation system, if the openings are on the rooftop

– ventilation system is very expensive to modify once the greenhouse is already built

– Problems are accentuated by the heat produced by the photovoltaic panels inside the greenhouse

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2. Problems of « light sharing » : crops are of lower quality

Quote « APREL »

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● 3. selection of plantations made after the construction of the photovoltaic greenhouse

● it is essential to consider the placement of crops when designing the greenhouse and not when the greenhouse is already built

Quote « APREL » Quote « APREL »

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in conclusion, many farmers have PV greenhouses with low agricultural yields in operation

producers try to find solutions to solve problems (additional ventilation, etc.) but it's very difficult and expensive

Quote « APREL »

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Summary :

● Each greenhouse project has its own characteristics associated with an agricultural project. Most of the installations currently in operation encounter difficulties during the first cultivation

● The loss of brightness currently leads to yield losses compared to conventional greenhouse systems.

● Thus, the quality of new projects must be controlled; any new project requires preparation involving the farmer during the design and should be supported by an expert or professional body.

● innovation must play a key role in overcoming problems

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Summary





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1) Develop a technical framework for photovoltaic greenhouses

based on monitoring by professional farmers' organizations (APREL)

Must allow actors to discriminate between "good projects", with a resilient and economically sustainable agricultural project, and "bad projects".

3) Enable innovation to develop

Unidentified photovoltaic Object

Flexible PV + storage, PV + Methanization...

In a context that encourages innovation of high environmental quality..........

2) Adapt the national financial support

→ Obligation to provide justification for agricultural production once the PV greenhouse is in operation

3 working axes to improve agricultural performances


2007 - 2010 2011 - 2014 2015 - 2018

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Concerning the engeenering of the projet :

● The geometry of the greenhouse must be designed according to future agricultural production

● Ventilation plays a key role to have a good hygrometry conditions and to avoid the accumulation of volatile components

● Cost of equipments useful for agricultural production (irrigation system …) must be integrated into the overall economics of the project

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Concerning the engeering of the projet :

● Serious partnership between the photovoltaic producer and the farmer, from the design to the commissioning of the installation

● Construction phase of the PV greenhouse (earthworks and structural installation) can damage the supporting ground that will be used for crops:

→ ground must be protected during the construction of the greenhouse, especially if the work is made by a subcontractor

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Concerning agricultural equipment in the greenhouse :

● All agricultural equipments: irrigation, ventilation must be sized from the beginning of the project.

● Obligation of an irrigation system sized in relation to the areas to be cultivated

● Good isolation of the cultures from the external environment : the installation of a physical barrier against bio-aggressors is important to reduce the use of biocides, particularly synthetic ones

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Concerning the « light sharing » between photovoltaic and agricultural productions :

● Placement of PV panels on the rooftop must be studied according to the placement of agricultural crops inside the greenhouse on an annual cycle (winter sun, summer sun)

● Geometry of the PV greenhouse must optimize the lateral lighting supply. Thus, it is necessary to prevent any "dark cavity effect" in the center of the greenhouse

● by allowing light to be supplied to the centre of the greenhouse (light shaft)

● by reducing the density of PV panels on the rooftop at the center

● Electrical devices must cover the greenhouse superstructure elements as much as possible and not prevent the passage of light (example cable tray) ;

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Definition of an adapted agricultural project:

● During the design of the project : make a crop placement scheme, which takes into account the possibilities of providing natural lighting.

● This strategy must be coherent with the business model (period of sale of agricultural production)

● ;

Quote « APREL »

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● A PV greenhouse is a complex and recent tool ; yet we do not have enough feedback to establish appropriate agricultural practices

● Nevertheless, some framework principles should be respected. For example to choose plant species ;

● Plant species that do not benefit from maximum and direct sunlight (algae, orchids, undergrowth fruits,...) should be the better ones for growing in photovoltaic greenhouses

● Even if it seems obvious, the crops produced have to be sold (quality and quantity).

● The income from agricultural production must be balanced with the income from photovoltaic production .

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Summary


2. Feedback of some PV greenhouses projects in France



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Interesting innovations...

● Already visible effects on certain new projects But results have to be demonstrated

● Example of new systems into a recent PV greenhouse

● Homogenization of light Inside the greenhouse

● Choice of the type of agricultural crop from the design stage

● Use of material " anti condensation " to help the ventilation system

● The farmer is assisted by a professional body to start his first crop cycles

● Development of a real engineering agrivoltaic

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...that must demonstrate their effectiveness

Feedback on agricultural yields in new photovoltaic greenhouses is essential

These innovations must demonstrate their effectiveness:

– with crops with sufficient yield

– with quality crops that can be marketed

– over several years and harvest seasons.

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Others agrivoltaic Systems

Unidentified PHotovoltaic Objects

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Reference websites

Information about PV greenhouses in PACA http://www.paca.developpement-durable.gouv.fr/IMG/pdf/plaquette-sel-flash-acrobat.pdf

Agricultural monitoring of photovoltaic greenhouses https://www.aprel.fr/publication_aprel.php?id=8

*APREL : Association Provençale de Recherche et d'Expérimentation Légumière

http://www.paca.developpement-durable.gouv.fr/IMG/pdf/plaquette-sel-flash-acrobat.pdf

http://www.paca.developpement-durable.gouv.fr/IMG/pdf/plaquette-sel-flash-acrobat.pdf

https://www.aprel.fr/publication_aprel.php?id=8

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Thank you for your attention

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