Coriolis Seminar - Agrivoltaics : brilliant idea or dead end ?

Farmers always produced both energy and food for human societies. Prior to the coal and oil age, farmers were the primary energy producers, nurturing the grass and grains that powered animals - the main mode of transport and work. This critical role is set to re-emerge, albeit in a different form. Agrivoltaics (AV) has the potential to reshape the future of solar energy generation in profound ways. AV combines photosynthesis, the process by which plants capture solar energy, with the photoelectric effect, the principle behind solar power generation. Basically, AV consists in solar PV panels on top of crops or pastures. The first experimental Agrivoltaic system was installed in Montpellier, France, in 2009. During the last decade a large panel of AV technologies emerged, with more than 50 private companies active on the European market since this year. Some of the more advanced technologies use mobile panels that are driven by the requirements of the crops for light, and may protect crops or animals against the stresses induced by climate change. 200 000 ha of AV systems, which is only 0.6 % of the agriculture area in France, have the potential to produce as much electricity as our current nuclear plant system in France, without decreasing the agriculture production. The expectations are huge, but the pitfalls are deep.
The design of an AV system is not obvious. The yield of crops in AV systems is difficult to predict as the shade pattern of an AV system is not typical. Most countries allow AV systems on croplands only if the crop productivity is maintained or slightly reduced, as in Japan and Germany, with 80% and 66% minimum relative yield (RY) required, respectively. In France, a decree on agrivoltaics is currently prepared and considers to require that the crop loss is only 10%, which would make France the country with the most demanding regulation. Is that feasible? A synthesis of published data for crop productivity under AV systems evidences that the RYs of crops decrease rapidly when the panel density increases. The search for an optimum is the key. There is a need to assess whether a photovoltaic project deserves to be considered an AV system. While an AV system was originally defined simply as a dual system with both crop and electricity production on the same plot, several more detailed definitions were produced recently in various policies or labels in France, Japan, Italy and Germany. These definitions insist that the main condition for qualifying as an AV system is that the crop yield is maintained (if not improved) under the system. A very animated discussion is taking place in Europe and especially France about the regulation of agrivoltaics, and the share of the revenues between electricity companies, farmers and landowners. AV is not only an unmature technology, it is also a very political issue. AV may generate inequalities, frustration and havoc in our contryside. The conditions for a sustained, participatory and well-shared AV scheme will be detailed.