Agrovoltaics - A potential approach to mitigating the effects of climate change in the vineyard

The threat of the impacts of climate change on wine quality has sent winemakers scrambling for mitigating solutions to include: moving to higher altitudes; adding more heat tolerant varieties to the mix; adjusting canopy strategies; and agroforestry. But it is not only increased heat that is of concern; we also expect changes in the intensity and frequency of all adverse climatic events.

Agrovoltaics is an emerging approach that may be deployable in this engaged battle against and unleashed and unruly Mother Nature. Otherwise known as solar sharing, agrovoltaics places solar panels on the same land where crops are grown, allowing farmers to harvest the power of the sun twice.

Source: https://www.unitedwind.com/
innovation/sustainable-future-with-agrovoltaics/

Beyond a certain point -- the light saturation point -- light does not increase photosynthesis. Rather, the additional light causes the plant to sweat, increasing its demand for water. Solar panels can be positioned to allow crops just the right amount of sunlight with the excess diverted to electricity production. 

From the solar energy provider's perspective, it is expensive to clear and level land for the deployment of solar arrays. It would be much less expensive to deploy these arrays on land that is already in use.

Plants help to keep the solar panels cool, making them more efficient. It has been shown that solar panels emplaced above crops produce up to 10% more electricity than solar panels without underlying plants.

Large-scale solar arrays produce a so-called "heat island effect where temperatures in the vicinity are elevated as a result of the operation. Attempts have been made to reduce this effect by installing gravel beds below the arrays; the results have been unsatisfactory. Replacing the gravel beds with vegetation, on the other hand, has yielded significant positive effects.

According to an Oregon State University study, converting 1% of American farmland to agrovoltaics would:

• Allow us to meet national renewable energy targets
• Save water
• Create new revenue opportunities for small farmers.

Crops best suited for agrovoltaics are limited to those which are grown and harvested by hand or with the aid of small machinery. These include (NRCC):

• Shade-loving pollinator crops
• Bedding plants
• Small fruit trees and shrubs
• Vegetables
• Livestock.

There has been at least one vineyard trial utilizing this approach. The French solar provider Sun'R and its subsidiary Sun'Agri have established and experimental program in southern France in partnership with Environment and Energy Management Agency. The trial involves a 600 sq m dynamic system installed in a 1000 sq m Grenache vineyard. The system is comprised of 280 panels (capable of producing 84 kW of electricity) each placed 4.2 m above the vine rows. Movement of the panels is arbitrated by an AI system such as to optimize sunshine and water access as well as to shield the vines from heavy rain, frost, and heat.

Initial results from the trial show that:

• The panel structure shelters the vines from stunting during heatwaves
• The system reduces water demand by 12 - 34% due to a reduction in transpiration through the soil
• The aromatic profile of the berry has improved, with 13% more anthocyanin and 9 - 14% more acidity evident.

Much more data need to be presented as to the break-even size required for a vineyard to embark on this path, who benefits, who pays the cost, etc., before a more definitive position can be taken as regards this approach. But the promise is clear.

©Wine -- Mise en abyme