The Cooperative Society Newsletter
July 2023, Issue 42
By E. G. Nadeau
The word agrivoltaics, defined as “the use of land for both agriculture and solar photovoltaic energy generation,” was coined in 1981, but it has not become a significant area of research and development until the past few years. This is a brief article about how agrivoltaics can be a boon to both clean energy production and farming.
NREL, the National Renewable Energy Laboratory in the United States, has been assisting a number of agrivoltaic experiments since 2020. Some examples of solar farming are presented below.
- Jack’s Solar Garden is researching a diverse array of crops under solar panels in Colorado.
- BlueWave Solar is combining solar panels with blueberry farming in Maine.
- Pine Gate Renewables and other organizations are experimenting with elevated solar panels above cranberry bogs in Massachusetts.
- Silicon Ranch is partnering with White Oak Pastures to graze several thousand head of sheep in combination with solar panels in Georgia, Tennessee, and Missouri.
- Bare Honey is locating honeybee hives near solar panels that provide shade for pollinator-friendly plants on farms in Minnesota.
- Cattle are grazing among solar panels on Knowlton Family Farms in Massachusetts.
Agrivoltaics is taking off in other countries
- Researchers in South Korea are successfully growing broccoli underneath solar panels.
- Solar panels are being used to reverse desertification in Algeria.
- A large solar power installation on salt flats in China is serving a triple function of facilitating salt farming, growing shrimp, and generating electricity.
- A Kenyan project is using shade from solar panels to shelter vegetables from heat stress and water loss.
To put it simply: Solar panels produce clean energy; reduce the cost of electrical energy; reduce global warming; provide lease income to farmers, who in turn spend money in their local communities; generate jobs; provide shade that many crops and livestock need to thrive; are more efficient when they don’t get too hot; increase carbon sequestration; and can be configured in a variety of ways to accommodate different agricultural products.
What’s the combined result? Something in the range of a win-win-win-win-win-win-win-win.
Controversy
With all of these benefits, why all the controversy about solar arrays on farms? One source of opposition is that some neighbors don’t like the looks of a large expanse of solar panels. Whether a field of solar panels is ugly or beautiful is in the eyes of the beholder. No matter what the potential benefits are, some local community residents are likely to express concern about the NIMBY (not in my backyard) problem.
One genuine problem that some solar arrays cause is that they reduce the amount of productive agricultural land. This article makes the case that more and more solar arrays are being constructed in ways that complement and, in some cases, improve agriculture, rather than harm it.
By some estimates, solar panels may need to be located on 1% of the land area in the United States and other countries. Some panels may be on rooftops or on land surfaces that are not agricultural, but there is no question that many of the solar arrays will need to be located on farmland. Thus, it is critically important to develop a range of strategies in which such arrays and farming are mutually beneficial.
We also shouldn’t forget that much farmland is currently not being used sustainably. For example, in the state of Wisconsin alone, a million acres of corn are used for the production of ethanol, a “renewable” energy use that is considered by many to be highly inefficient in, if not detrimental to, combating global warming. Agrivoltaics can play a very constructive role in reducing this kind of wasteful production and replacing it with more sustainable agricultural uses.
Let’s dig a little deeper into the list of ”wins” cited above
Solar panels produce clean energy.
No need to make a case for this. It’s not a subject of much debate.
They reduce the cost of electrical energy.
The cost of solar electricity has dropped dramatically during the past decade or so, and is on track to keep dropping. Solar is the least expensive of all sources of electricity.
They reduce global warming.
Because solar panels do not emit carbon dioxide or other greenhouse gases, they meet our electricity needs without raising the world’s temperature.
They provide lease income to farmers.
“Farming the sun” can be a lucrative source of income for many small- and medium-size farms, sometimes making the difference between staying on the land or selling out. Those farmers, in turn, spend some of this money in their local communities.
They generate jobs.
There are over a quarter-of-a-million solar jobs in the United States. Constructing solar arrays requires a significant amount of labor. Even though the labor for each array is not huge, the anticipated growth of these arrays over the next several decades will keep hundreds of thousands of people employed in the United States alone.
They provide shade that benefits crops and livestock.
Sheep, goats, cattle, and other livestock can benefit from the cooling effects of taking a break under a solar panel. In the case of cattle, the poles supporting the panels must be built strongly, because cows enjoy rubbing up against them. Many crops benefit from the shade provided by solar panels, especially on farms located in hot, dry areas.
Solar panels are more efficient when they don’t get too hot.
Crops can help to cool them by generating water evaporation, reducing heat reflection, and letting more air pass under the panels (because they are mounted higher on cropland than on non-crop surfaces).
Some crops sequester carbon.
Some crops, especially perennial grasses, are excellent at sequestering carbon both above and below ground. Grasses grow very well under solar panels. A recent article by All Native Seed, LLC, put it this way: “While trees have long been used for carbon sequestration, native grasses . . . are increasing in popularity for this purpose along with other benefits. Grasses like switchgrass and Miscanthus have deep, complex root systems that are ideal for storing carbon in the soil. Their root structures also help stabilize the soil, increase moisture levels, and retain nutrients. . . . Finally, grasses . . . establish in 1-3 years so maximum carbon sequestration is realized much sooner than with trees.”
Custom-designed solar panels.
Solar panels can be custom-designed to address different kinds of agriculture. Solar panels can be installed at different heights and in different configurations so that livestock and agricultural equipment can pass underneath them, and crops can be planted and harvested efficiently.
Conclusion
As the use of solar panels on agricultural land increases in the future, the two forms of gathering energy from the sun will become more and more mutually beneficial. We are in the very early stages of figuring out the best ways to make this happen.