Powering sustainable agriculture
by Ben Davis
In our Fall 2019 issue, we introduced the concept of agrivoltaics—a farming system in which solar panels are installed directly above crops. This emerging research is the work of Chad Higgins, OSU professor of biological and ecological engineering, and it aims to solve major issues concerning water and energy by harvesting electricity on farmland.
When we first introduced Higgins’ vision for a “Farm of the Future” he shared how an entire farming system might be reimagined for maximum sustainability. By placing solar panels above crops, farms could not only be more productive, but actually generate energy on-site to power electric farm equipment and precision ag technologies—while also helping the crops conserve water.
That vision will soon become a reality. Higgins is creating a working prototype model of this concept at OSU’s North Willamette Research & Extension Center in Aurora, OR. The five-acre model called the Staterra Center (which means “balanced earth”) is expected to be fully functional by Fall of 2021. Having a fully functioning agrivoltaic farm will allow Higgins to demonstrate a proof of concept so that the agricultural industry can feel more confident making the investment to potentially transform their fields to this new model. Higgins and his co-author, Kyle Proctor, a doctoral student in his lab, recently published new findings that an area about the size of Maryland would be needed for agrivoltaics to meet 20% of U.S. electricity demand. That’s about 13,000 square miles, or 1% of current U.S. farmland.
The concept of agrivoltaics can seem counterintuitive at first—you may wonder how plants and solar panels can co-exist without being in direct competition for sunlight. Or how exactly solar panels can help crops conserve water. Central to the concept are two surprising facts about the relationship between solar panels and plant life.
1) Plants need less water with solar panels above them
Plants have a limit to how much sun they can actually use. It’s called the light saturation point. Once reached, any light beyond that point does not increase photosynthesis or help the plant grow, it only increases the plant’s water demand. It simply makes the plant sweat, which in turn makes it more “thirsty.”
Solar panels can be positioned to allow plants just the right amount of sunlight, and then the excess sunlight can be harvested for electricity—helping plants retain water by keeping them from sweating beyond their light saturation point.
2) Solar panels produce more electricity with plants underneath them
Plants help keep the solar panels cool, which makes them more productive. Higgins’ studies have shown that panels positioned above plants produce up to 10% more electricity.
The benefits of agrivoltaics
Water, energy, and agriculture are the bedrock of modern civilization. And while many technologies have advanced these components separately, few have aimed to address all three components at once.
This new technology promises to improve food production and reduce water use, while also creating energy and additional revenue. Essentially, when solar panels are placed on the same land where crops are grown, it allows growers to harvest the power of the sun twice.
If converting just 1% of American farmland to agrivoltaics could meet our national renewable energy targets and create a sustainable long-term food system, the potential for this approach could be truly transformative. What’s more it can also create new revenue opportunities for family farms which are currently facing increasing economic challenges, with a 23% increase in bankruptcy filings over the past year.
The problem with current methods
Agriculture uses an enormous amount of resources. It takes A LOT of water and energy to grow all of our food. 85% of global water consumption is used for irrigation, and over one-third of all greenhouse gases can be attributed to agriculture.
At the same time, our demand for food is only growing. The global population, now around 7.5 billion, is estimated to reach 9.8 billion people by 2050.
With current agricultural methods, there will be nowhere near enough water to grow even the current level of food production by 2050. And we are all aware of the high cost of fossil fuels on both our wallets and the environment.
Agriculture has always adapted to meet the dynamic needs of a changing society. Innovations in technology have driven incredible progress over time – from tractors and pest management to breeding and genomics. Today, most growers are accustomed to exploring new methods of addressing emerging challenges in agriculture, and continue to look for ways to mitigate risks brought on by a changing climate.
The agrivoltaic solution
Agrivoltaics is a symbiotic relationship where both the solar panels and the crops benefit because they help each other perform better.
The electricity can be used to run the farm with electric tractors and equipment, and to power precision ag technology that helps further reduce water usage. Surplus energy can be stored in battery banks or sent to the grid for consumer use.
It’s a win-win-win relationship between the three most foundational elements of modern life: food, water, and energy.
This type of systems-thinking approach is the only way to solve the intertwined issues of long-term sustainable farming, energy production, and water conservation.