Concentration of CO2 in the Atmosphere

Grazing Sheep Beneath Solar Panels Benefits Sheep and Farmers

Sheep grazing under solar panels. (Wikimedia Commons, https://bit.ly/AgrivoltaicsSheep)

George Harvey

Most of my life, I have lived in rural settings. When I was five to fifteen years old, I lived in the corn belt in Illinois. I have lived among mixed farms in New Hampshire. I have worked on a farm, myself, in the Garden State of New Jersey. One thing that I learned early was that farms can go out of business because of financial stress. People don’t farm because it’s easy. They farm because they love it.

Farmers are dependent on weather, but that might mean depending on rain, when there wasn’t any, or a time to dry out, when rains persisted. One other thing farmers can depend on is that high prices come when they don’t have anything to sell, and when they have managed to grow a big crop, prices are low.

Farmers can get some help by diversifying. They might lose much of a corn crop, and that could be really bad, but if they raise pastured cows for milk, chickens for eggs, or vegetables, they might get through a string of not-so-good years. Resourceful people, farmers make do with what they have, and they generally get by. But not always. Sometimes the mortgage comes due before the money to cover it comes in.

Today, farmers may have a new source of income: renewable energy. One problem with that is that they might need permission from people who don’t understand them and aren’t inclined to agree with the goals they have for their land.

Sometimes, such people tell farmers that they don’t like the way solar panels look, especially where the land has long been used for agriculture. They don’t want agricultural land to be used for other purposes, so they try to prevent solar panels from being installed. This is especially sad, because if the installation can be blocked, it might just put a farmer out of business. And once a farm has gone out of business, it is likely never to be brought back to production.

Sadder still is that solar panels on a farm, if they are properly planned, can give a farmer a huge benefit that goes beyond getting the bit more money to keep the farm going. The solar panels can actually improve agricultural production on the farm, by combining photovoltaics with agriculture in what is called agrivoltaics.

One of the most obvious applications of agrivoltaics is solar panels with grazing sheep. Any solar array that has grass under it has to have the grass cut. Sheep do this for free. And they do it very well. But there are other benefits.

A recent article in The Guardian took a look at agrivoltaics and found that the presences of solar panels actually improved the production of the sheep (bit.ly/PvsGrazing). The article examined grazing on a farm in the Australian state of New South Wales. The sheep liked grazing in the shade of the solar panels. They always had at least some very fresh, soft grass to eat, because the solar panels have drip lines. And the same number of sheep can produce 15% more wool under solar panels than they would in the open.

To me, this is not all that surprising. Analysis by the Fraunhofer Institute in 2018 and reported in CleanTechnica, showed that potato plants grown under solar panels outperformed those grown in the open, producing 186% as much during an especially hot, dry summer (bit.ly/Fraunhofer-1). The result was reinforced by a study from the University of Arizona. The crop was cooler in the shade during the daytime and warmer at night. It is also exposed to wind less and needs less irrigation, a benefit appreciated by people in Arizona.

A similar study done the following year produced much the same sorts of results according to Science Daily (https://bit.ly/SDagrivoltaics). Two different kinds of peppers and one of tomatoes were planted on identical fields, except that one was under solar panels. For one type of pepper, the one with the solar panels did as well as the other. Tomatoes growing under solar panels produced about twice as much as those growing in the open. And the second type of pepper produced about three times as much as the same type in the open. Some species are not especially sun-loving.

Tomatoes, a gardening friend told me, are understory plants in the wild. Clearly, this would tend to mean they will do better in at least partial shade. Solar panels provide partial shade. And the same sort of thing is true for animals. Many animals, possibly most, will benefit from being screened from the sun, and that is true for sheep.

There are things to remember here. First off, a solar array should be designed specifically for sheep to graze under the panels, if that is what is wanted. If the array is designed without consideration for the sheep, it will only have one way to perform at its best, which is luck.

Another thing to keep in mind is that other animals will be very likely not to do as well as sheep. Cows tend to push against all sorts of things, including the racking for solar panels. And goats will want to climb up on the panels.

Finally, we should add that the exact nature of the solar panels themselves be taken into account. Though I have not seen any indication that panels with cadmium or arsenic have caused health problems, I would prefer not to use them in an agrivoltaic system. That should be easy anyway, because the majority of panels do not have such chemicals in them.

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