The most productive places on Earth for solar power are farmlands, through agrivoltaics

A new study finds that if less than 1% of agricultural land was converted to solar panels, it would be sufficient to fulfill global electric energy demand.


KEY POINTS
  • A new study finds that if less than 1% of agricultural land was converted to solar panels, it would be sufficient to fulfill global electric energy demand.
  • The study, by Oregon State University researchers, has been published in the journal Scientific Reports.
  • The results have implications for the current practice of constructing large solar arrays in deserts.

The study, published in the journal Scientific Reports, finds that if less than 1% of agricultural land was converted to solar panels, it would be sufficient to fulfill global electric energy demand. The concept of co-developing the same area of land for both solar photovoltaic power and conventional agriculture is known as agrivoltaics.

“Our results indicate that there’s a huge potential for solar and agriculture to work together to provide reliable energy,” said corresponding author Chad Higgins, an associate professor in OSU’s College of Agricultural Sciences. “There’s an old adage that agriculture can overproduce anything. That’s what we found in electricity, too. It turns out that 8,000 years ago, farmers found the best places to harvest solar energy on Earth.”

The results have implications for the current practice of constructing large solar arrays in deserts, Higgins said.

“Solar panels are finicky,” he said. “Their efficiency drops the hotter the panels get. That barren land is hotter. Their productivity is less than what it could be per acre.”

For their study, OSU researchers analyzed power production data collected by Tesla, which has installed five large grid-tied, ground-mounted solar electric arrays on agricultural lands owned by Oregon State. Specifically, the team looked at data collected every 15 minutes at the 35th Street Solar Array installed in 2013 on the west side of OSU’s Corvallis campus.

The researchers synchronized the Tesla information with data collected by microclimate research stations they installed at the array that recorded mean air temperature, relative humidity, wind speed, wind direction, soil moisture and incoming solar energy.

Based on those results, Elnaz Hassanpour Adeh, a recent Ph.D. graduate from OSU’s water resources engineering program and co-author on the study, developed a model for photovoltaic efficiency as a function of air temperature, wind speed and relative humidity.

“We found that when it’s cool outside the efficiency gets better,” Higgins said. “If it’s hot the efficiency gets worse. When it is dead calm the efficiency is worse, but some wind makes it better. As the conditions became more humid, the panels did worse. Solar panels are just like people and the weather, they are happier when it’s cool and breezy and dry.”

Using global maps made from satellite images, Adeh then applied that model worldwide, spanning 17 classes of globally accepted land cover, including classes such as croplands, mixed forests, urban and savanna. The classes were then ranked from best (croplands) to worst (snow/ice) in terms of where a solar panel would be most productive.

The model was then re-evaluated to assess the agrivoltaic potential to meet projected global electric energy demand that has been determined by the World Bank.

Higgins and Adeh previously published research that shows that solar panels increase agricultural production on dry, unirrigated farmland. Those results indicated that locating solar panels on pasture or agricultural fields could increase crop yields.

Co-authors on the recent study were Stephen Good, an assistant professor in OSU’s Department of Biological and Ecological Engineering, and Marc Calaf, an assistant professor of mechanical engineering at Utah State University.

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  1. Dear PV Buxx Editorial Staff,

    While I relish and look forward to each and every article you guys share, I’m totally in disagreement with the premise of this article. We need our farmlands to grow our raw food stock, feed our animal stock, produce oxygen, ground cover, protect our diminishing water tables, create and protect our precious topsoil, We DO NOT need to cover this precious and limited space with solar panels. This is strictly a not so shuttle way of promoting a specialized business and making a buck, over what’s right for the environment. Shame on you!, you are better than this.

    A BETTER SOLUTION is to do a make over of all our asphalt/concrete roadways, pathways, and parking lots in the world and cover them with electricity producing solar panels, let’s call them Solar Roadways. Creating something that takes the wasted space most of the day when no cars are traveling over them, pollutes and heats up our environment, and gives us back the ability to produce more energy than we can imagine ever using, which we can directly store and consume the moment it is installed. Roadways that help mankind to be a better world, WITHOUT giving up any precious resources we already have.

    You have a huge fan base, and most of the time you look to be trying to help us all learn and see how technology can make this a better place to live for both ourselves and our children to come. But this time you missed the mark completely on sustainability and healthy worldviews, just to help someone make a buck.

    Let’s work together on building a better world, one we can all be proud to have been a part of, that helps all mankind live a healthy and sustainability lifestyle by protecting the precious resources we already have and building new ones that compliment not destroy those that already sustain us and our healthy environment we live in.

  2. Dear Mr Grothe:

    I wish to respectively disagree with your comments. I don’t think it is appropriate for you to suggest that PV Buzz is to be shamed by this article in the slightest.

    You wrote: “We need our farmlands to grow our raw food stock, feed our animal stock, produce oxygen, ground cover, protect our diminishing water tables, create and protect our precious topsoil, ”

    My response: food can be grown underneath a PV array, animals can be raised under a PV array, oxygen production is not restricted by a PV array, ground cover is not diminished by a PV array, water tables are not affected by a PV array, topsoil is **protected** by a PV array.

    Alberta could generate all of its electrical energy with a solar PV array extending 45 km x 45 km, which is 1% of our agricultural land.

    What is puts agricultural land at risk is urban sprawl and roads. I see that you are a strong proponent of solar roadways… but these have been shown to be not worth their while (for very good reasons). There is so much more to a roadway than merely “wasted space”.

    I welcome your comments.

    https://www.producer.com/2013/03/farmland-in-short-supply-across-alberta/

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