Agriculture

Harvesting the Sun

A new generation of farmers may soon reap crops and electricity.

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Solar panels
Nellis AFB

In a video posted this spring at Newsweek.com, a third-generation almond farmer in California's Central Valley explains how the state's longstanding drought has necessitated a shift in strategy. "We have land, we have lots of sunshine, but we have no water," he says. "So we better think of something else to use the asset for."

The answer he came up with was solar farming. As the camera pans a dusty array of photovoltaic (PV) panels, the man notes that almond orchards and solar farms have similar lifespans of around 20 to 25 years. "When it's up, you can pull it out," he says of the latter. "If we have water at that time, and an almond orchard is still viable, we can replant that, or some other kind of crop. Or we could put new-technology solar in."

With its lingering close-ups of parched soil and its sad-keyboards soundtrack, the video strikes an emphatically declinist note. The bounty of yore, it suggests, is a distant Eden, and our future is one of compromise and diminishing returns—not as fertile as the past, not as lucrative, not as fulfilling.

The farmer himself buys into this proposition: He presents a future of either crops or panels. But recent research suggests the choice may not be so clear-cut. That's because a new hybrid innovation called agrivoltaics is allowing farmers to raise crops on the same land that solar installations occupy.

The idea of doubling down in this manner was first proposed by a couple of German scientists in a 1982 research paper called "On the Coexistence of Solar Energy Conversion and Plant Conservation." In 2010, a French agronomist named Christian Dupraz decided to put the theory into practice.

Along with his colleagues at France's National Institute for Agricultural Research, Dupraz divided a small field in Montpellier into four plots. Two of the plots remain fully exposed to the sun; two others are covered by PV panel arrays. In one of these plots, the arrays were constructed at full density, or what Dupraz described as "optimal spacing for electricity production."

In the other, the arrays exhibit only "half-density." That is, there was more space between the panels to allow for greater sun exposure. In both instances, the arrays were mounted 13 feet above the ground via support pillars spaced approximately 20 feet apart—this way, farm machinery could still operate in the plots.

Dupraz's general hypothesis was that the lack of sun would inhibit crop production but that the shade provided by the PV panels might also increase water efficiency and thus make up for some of the reduced sun. In a series of experiments conducted over the course of several years, Dupraz, Helen Marrou, and others grew and carefully monitored a variety of crops at Montpellier, including wheat, cucumbers, and several kinds of lettuce.

What they have found to date is that crops grown under the full-density arrays fare less well than those receiving full exposure from the sun. But those grown under the half-density arrays do surprisingly well—essentially equaling the productivity of the control plants, and in some instances, even exceeding them.

One reason for this is because of the phenomenon Dupraz had hypothesized about: The shade created by the panels allowed the plants to utilize water more efficiently than those that were fully exposed to the sun. But as Marrou described in a 2013 research paper, the plants also increased their leaf area and altered the arrangement of their leaves. Faced with less sun exposure, they adapted to become more efficient light harvesters.

Courtney White, founder of the nonprofit Quivira Coalition, writes about agrivoltaics in his 2015 book, Two Percent Solutions for the Planet. "It was the Goldilocks principle at work again: Too much shade hurt the crops, too little hurt electricity generation. Everything had to be just right."

What makes agrivoltaics especially compelling is how this balancing act increases overall productivity. According to Dupraz's calculations, combining solar and farming can potentially make the land 60–70 percent more productive.

For that third-generation California almond farmer, agrivoltaics is not a viable option at the moment: His farm lost its access to water after a shift in federal policy earlier this year, and attempts to drill wells on his land came up dry. Thus, he currently lacks the ability to hydrate any kind of crops, even ones not quite as water-dependent as almonds.

But the idea behind agrivoltaics—that land need not be reserved for one use at a time—will be essential in coming decades. Over the next 35 years, global population is projected to grow from seven billion to nine billion. And around 2.5 billion people, mostly in China and India, will enter the middle class. This growth—in both population and wealth—will put even more pressure on scarce natural resources and already-straining social institutions.

And yet, in their 2014 book Resource Revolution, former McKinsey consultants Matt Rogers and Stefan Heck see opportunity where others see looming catastrophe. "While labor productivity has improved almost 100 percent over the last two decades," they write, "resource productivity has increased only 5 to 10 percent—and it's not because there isn't room for improvement."

In their estimation, the vast new coming market of global middle-class consumers gives entrepreneurs an incentive to use information and industrial technology to extract far more value from existing resources.

As the world urbanizes, many observers have come to believe in the virtues of increasing density. While cities were once equated with disease, crime, and vice, they're now associated with higher wages, more jobs, expanding innovation, and greater environmental sustainability.

"The average Vermonter…consumes more than four times as much electricity as the average New York City resident, has a larger carbon footprint, and generates more solid waste, backyard compost bins notwithstanding," writes David Owen in his 2009 book Green Metropolis. "In terms of sustainability, dense cities have far more to teach us than solar-powered mountainside cabins or quaint old New England towns."

Intensifying land productivity—especially by combining agricultural with industrial uses—goes against the vogue for free-range, organic farming practices. High-efficiency agriculture doesn't create the best optics for attracting well-heeled Whole Foods customers seeking heirloom tomatoes raised in 18th century–esque settings. But switching to agrivoltaics makes financial and environmental sense. Not only does it extract greater productivity from a given piece of land via multitasking, but these simultaneous uses are designed to complement each other in synergistic ways. In a world where water is only going to get scarcer, turning to growing environments with built-in shade is itself a form of conservation.

A Stanford research scientist named Sujith Ravi has noted another way agriculture and photovoltaics can complement each other. Currently, many California solar farms are located in desert habitat. But when dust and dirt accumulate on the PV panels, their efficiency can drop substantially. So operators often use water to both wash panels directly and to dampen the ground underneath them to mitigate dust. Ravi theorized that that water would go to better use if there were crops there to take advantage of it. Using computer models, he explored the feasibility of growing agave—a crop with low water requirements and the potential to be used as a biofuel (or to make tequila).

Ravi has yet to test this approach in the real world. And Dupraz's own experiments have been relatively small. But if agrivoltaics is feasible at scale, it could play an important role in California's economy in coming years. In 2008, Governor Arnold Schwarzenegger signed legislation that California's public utilities must serve at least 33 percent of their load with renewable energy by 2020. Utility providers are looking for ways to reach this goal, and one possible route is through large-scale solar projects.

It's not necessarily that easy to find the land for such projects. Frequently, permits have to be procured and environmental analyses conducted before construction can begin on wild lands. In such instances, there are typically questions about displacement of sensitive species, objections over the loss of open spaces, and other similar concerns.

Agrivoltaics presents an opportunity to place large-scale solar installations on flat, sunny, privately owned land near existing electrical grid infrastructure. And increasing the productivity of land that's already in use gives farmers an added revenue stream while minimizing new development of wild spaces. It suggests a future where sustainability arises from innovation and the pursuit of plenty, not from privation. Let the carbon-neutral margaritas flow!

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28 responses to “Harvesting the Sun

  1. I wonder how much red tape is required to mix solar panels and agriculture, to string new power lines, and to otherwise upset the land use bureaucracy that has developed over the last 100+ years. One would hope the enviro freaks would step aside, but that’s about as likely as any entrenched power group voluntarily stepping aside when reality makes their mission less relevant. One can only imagine the court battles over environmental impact statements on repurposing farm land that hardly anyone but farmers ever see.

    1. I, too, look forward to the pseudoscience justifying “Voltage Contamination” scare in 20 years.

      1. Yep. Nothing in the way of real progress more than progressives.

  2. Time for the unicorns crapping skittles.

    1. You know that is going to require extensive regulations. And PETA will insist on being custodians for any revenue generated from the unicorn shit. As it is the unicorn’s intellectual property

  3. The only reason farms can make money from solar is due to the govt subsidies andrules for payment. Solar power is very limited in value since it is basically uncontrollable and dumped onto the grid when the sun shines, not when the grid needs it. California counteis are filled with farmers switching to solar. The govt rules and subsides will change and solar farms will become passe.

    1. Solar has a lot of future potential. But the technology has severe limitations currently.

      1. Solar has *always* had future potential and seems like it always will.

      2. How can such a dilute and intermittent energy source every be useful outside of a few niche uses like keeping satellites running?

        1. Innovation making energy storage more efficient & cheaper. Things change, and there are a lot of good reasons to improve capacity & get solar right that arent driven by government fiat.

          1. Economical storage is a pipe dream at this point. Batteries (at this point) have lots of nasty shit in them, which progs ignore.

        2. How about using it to run desalination plant instead of using other power sources?

  4. are we really going to trot out the mankind’s population growth is straining the food growing resources falsity that has popped up time and again over the last 50 years?

    We always seem to be just a few years away from starving as a species.

    1. It’s a great excuse for maoist/soviet style policy enactment. Just like climate change.

    2. i didnt get that impression from the author at all. did we read the same article?

  5. THE BIG YELLOW ONE’S THE SUN!

    1. So, s’plain to me agin how you think the “ball” we’re on goes aroun’ the big yellow one?

      1. Why duznt the chinamen fly off?

  6. Greg,
    TWO PAGES to justify rent-seeking photo-voltaic generation?
    Here’s a hint; turn it loose absent any subsides or moonbeam-mandates and see what happens. Hint: If the land can’t grow cahs-crops since the water isn’t there, it’ll turn into grazing land.
    It WON’T grow photo-voltaic panels; they only grow when taxpayers pay someone to grow them.

    1. +1 non-GMO, organic, locally sourced, cruelty free mill levy

    2. thats a great plan Sevo. back here on planet earth, the socialist republic of california has no immediate plan to radically divest into a libertopian paradise. discussing politics in the present tense is relevant is pragmatic if not as ideologically pure as you would like it to be.

  7. It’s not ideology, Jay, it’s common sense. Solar and wind only make sense when locally installed. Then it’s cost effective because of subsidies. As with Tesla and Solar City cronies like Musk feast on government money and unless you are completely complicit in watermelon bullshit you have to accept that nat gas plants are idling waiting for when the wind quits and the sun doesn’t shine. Yet the cheerleaders for renewables fail to account for this when the costs are discussed. They lie, the costs are due to the intermittent nature of solar and wind yet they don’t include those costs when they lie about how cheap wind and solar are.

    On top of that, renewable subsidies go to the 1%. Do the rich dolts that buy Teslas really need a ten grand subsidy. Me thinks no fucking way.

    Seriously, should George Clooney get a ten grand subsidy to buy a fucking car that the 99% can’t even think about affording. I’ll go with no fucking way. If he wants said car, no skin off my ass. If he wants to help him pay for it, fuck off George.

    Are you really this much of a simpleton that can’t see the big picture here?

  8. as Michelle explained I am startled that any body able to earn $8039 in four weeks on the internet . Check This Out …

    http://www.infopay50.cm

  9. Up next,unicorn farms,for the children.

  10. The real problem with the Western U.S. is, of course, government policies and control over the water supply. That’s why that 3rd-generation farmer doesn’t have water for crops.

    Agrivoltaics sounds good, but again, the real problem isn’t coming up with new or innovative ideas, it’s going through regulatory red-tape (or bypassing it) in order to utilize these ideas.

    We don’t need subsidies to develop new technology and ideas; we need government to get out of the way.

  11. Google pay 97$ per hour my last pay check was $8500 working 1o hours a week online. My younger brother friend has been averaging 12k for months now and he works about 22 hours a week. I cant believe how easy it was once I tried it out.
    This is wha- I do…… ?????? http://www.online-jobs9.com

  12. Sure the sun is one of the energy sources that can make these electricity providers less rich

  13. Saving sun’s energy will be the last option to save lives.

    Status

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