Agrivoltaics: solar energy can be cultivated!

Combining agriculture and solar energy is possible. By intelligently sharing light, agrivoltaics can address several challenges: the effects of climate change on agricultural crops and land use conflicts. Lighting!

The idea was born in 1982[1], when the first solar park was built in California. The rise of photovoltaics is encountering installation limitations. Subject to strict standards, the construction of power plants must not be carried out on agricultural land. At best, the land must integrate a mix of uses (agropastoralism, for example). It is particularly to address the challenges of land use conflicts that research programs on agrivoltaics have emerged.

Solution for the future?

In France, for nearly ten years, researchers from INRA[2] and industrialists from Sun’R have been developing innovative solutions around agrivoltaics. Program code name: Sun’Agri. The systems implemented are inspired by multi-tiered crops (several species are grown on different levels). In agrivoltaics, the upper level is occupied by solar panels. Research has shown that it is possible to achieve agricultural yields equivalent to, or even higher than, those in open fields, with shutter systems controlling shade periods. The government has decided to support these innovative solutions, particularly through the dynamic control of solar panels, by increasing the volume of calls for tenders for agrivoltaics by 30% [3].

Heat wave to come

Reducing the amount of light can also help combat the effects of climate change on crops. Because while excessive temperatures are already affecting production, by the end of the century, simulations are worrying. Under the effect of water and heat stress and shorter ripening cycles, yields could fall by 35%[4] for Mediterranean vineyards. It is therefore necessary to develop solutions that introduce profound changes in practices for better adaptability to the climatic effects already at work.

Dynamics!

This is the bet made by a winegrower in the Pyrénées-Orientales. In Tresserre, five hectares of the Domaine de Nidolères are the subject of a unique experiment. Under the Sun'Agri program, the solar panels are mobile and remotely controlled by algorithms designed by Sun'R. The objective is to best support the ripening of the grapes, preserve their aromas, prevent them from being burned by the sun, and ultimately obtain better quality wines. Energy production takes a back seat, and "well-being" and plant production are prioritized. A solution that Sun'R also wants to apply to photovoltaic greenhouses, whose shading would be controlled at all times by mobile panels.

Greenhouse effect

Photovoltaic greenhouses are another solution for reconciling energy production and agricultural yields. By leveraging the light input, solar panels can optimize the growth of certain plants and reduce water consumption while producing energy. Several types of greenhouses have been developed in France since the early 2000s. The Agriénergie® concept from Akuo Energy is an illustration of this. The greenhouses recently developed by Tenergie are also. One of them, already built in Mallemort in the Bouches-du-Rhône, allowed for an initial harvest of 38 tons of yellow zucchini this summer. Agronomic studies and monitoring carried out by an independent organization are still underway to accurately measure the results. This is also what the specifications for CRE calls for tenders[5] for innovative solar technologies require. Another requirement: the presence of control agricultural areas, cultivated in the same way, but without photovoltaic panels for comparative monitoring. Conditions that can avoid windfall effects and the construction of photovoltaic greenhouses... which would remain without crops.

Cyrille Arnoux, web editorial manager

[1] A. GOETZBERGER and A. ZASTROW, On the Coexistence of Solar-Energy Conversion and Plant Cultivation, International Journal of Solar Energy, vol. 1, no. 1, ‎ 1 January 1982, p. 55–69

[2] National Institute for Agronomic Research

[3] Government Plan “Place Au Soleil”, June 2018

[4] Boutin F, Payan JC, 2012, Viticulture and Climate Change: Adaptation of the Mediterranean Vineyard. Agronomic Innovations 25, p. 193-203

[5] Energy Regulatory Commission

Photo credit: Sun’Agri