Orchardvoltaics – it’s just ripe

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When the “avocado smash” became an Australian cafe staple in the 1990s, few would have expected it to become the headline act of chic brunches in global metropoles. And yet, while living in New York City several years ago, it was surprising to observe a change in how Americans would respond to hearing an Australian accent. The days of Crocodile Dundee quotes, or questions about the marsupial mechanics of just how kangaroos carry schoolchildren in their pouches, were gone. The world was focused on “flat whites” and “avocado smashes.” Australia had seemingly gone from feral to fabulous, and all we have to thank is the national obsession with “avos” and opening cafes.

Global demand for avocados is so high that prices have smashed through the roof. Several years ago, Australian journalist Bernard Salt famously suggested younger generations would be able to afford a house in the country’s inflated property market if they just stopped buying “avocado amash’.” The ensuing scandal, which became known as “avocado-gate,” emphasized not only that Australia’s property market is the real scandal, but also that the fruit is, in all honesty, pretty pricey (and Australia is a country that produces its own).

Thankfully, solar PV provides a solution to both problems. We all know solar PV on rooftops can reap positive financial benefits, but as one innovative company in Israel is demonstrating, it can also help farmers’ profitability and the rest of us save on breakfast. Finally, it stands revealed that the proverbial stone which hit those two unsuspecting birds came from an avocado.

Doral Energy is at the forefront of Israel’s ambition to innovate its way to feeding a growing population with limited agricultural space. As such, Israel is looking to hit those same two birds over the head again, and Doral’s concept for dual-purpose land does just that. They call it “orchardvoltaics” – an agrivoltaic model integrated symbiotically with equally sophisticated orchard farming which allows both to prosper, and to profit.

Agrivoltaics is already a broad and varied method. Often solar is installed above existing crops, sometimes the panels retain or provide grazing land. There are even examples, specifically in South Australia, of large-scale solar farms providing protection for the regeneration of native vegetation. However, Doral’s innovation is novel in that the improved profitability of each system depends on the other, and the most symbiotic of relationships they have observed in orchardvoltaics so far is farming avocados.

Land limitations

“We all know that land is a limited resource,” Doral Energy CEO Yaki Noyman told pv magazine. “Especially in a crowded country like Israel, which is why the future is in dual land use.” Israel’s future is also in renewable energy, with a goal of 30% renewable energy production by 2030 – a goal acknowledged to be achievable only with dual land use. Interestingly, it is not only the land that is busy multitasking, but also bifacial PV modules.

At Doral’s pioneer facility in Kibbutz Maale Gilboa, the orchardvoltaic model’s synergetic relationship begins in the observation that, like solar, orchards come in corduroy-like neat rows. Above and between the orchard’s grooves of green corduroy stand solar panels sparkling like sequins in the sun, and long white sheets placed at the roots, which stretch away down the rows like an over-the-top wedding dress, reflecting sunbeams up at the high-standing bifacial panels and on the fruit. The former benefits with added energy generation; the latter through added quality and color.

“The exact amount of bifacial gain depends on the PV configuration (height, density, orientation, etc.) and module type,” Brecht Willockx, a researcher at Belgium’s KU Leuven and a member of a team testing agrivoltaics in pear orchards, said. “But the increased albedo by the white plastics will definitely increase the total gain.”

What is more, the groundsheets also prevent weeds from growing near the roots of the trees and slow water evaporation – another important saving, as research performed by Chad Higgins and Hadi al-Agele at Oregon State University inferred. “Agrivoltaics can provide a viable path toward water sustainability in agriculture,” they said.

Combining solar with orchards is “undoubtedly a good idea” – particularly for orchardists, continued Willockx. This comes down to the trellising method of orchard plantation itself, which utilizes the shade provided by the solar panels to protect fruits from excessive irradiance, while also allowing the trees to grow taller. Less water is also required due to reduced transpiration. This is particularly useful in Israel, where the sunny weather is excellent for solar energy nearly all year long, said Noyman. “Unfortunately, we cannot escape global warming, and days of extreme heat waves and lack of precipitation take a toll on farmers,” he added. The ability of agrivoltaic methods to create micro-climates, therefore, becomes particularly important.

Main challenges

According to Noyman, the biggest challenges to orchardvoltaics are on the “voltaics” side. “We do not see a big difference between an integrated plantation and any other solar project,” he said, adding that the barriers of connecting to a network and finding PPAs are the same barriers that exist in this model as well. “The challenges of a large-scale rollout include a connection to an overhead powerline, as well as a sub-station.” These are, of course, the challenges faced by any large-scale solar project, but not all of them can bear fruit before they start to generate energy.

There may be other challenges too, said Willockx. For instance, orchards are perennial crops, and it may not be that the effects of shading on yield will be visible for several years. Moreover, and this is a challenge faced by agrivoltaics generally, the balance between the crop and the solar is often not the most financially optimal. That challenge is, of course, strongly dependent on the country and indeed the crop. Given a highly irradiated country and a strong crop demand, financial optimization should not be a major issue.

Key opportunities

The benefits of orchardvoltaics seem particularly suited to semiarid regions like Israel. In a 2019 paper in Nature titled “Agrivoltaics provide mutual benefits across the food–energy–water nexus in drylands,” University of Arizona researchers found that a changing climate has semi-arid regions increasingly seeking resilience strategies to manage expanding populations and the concordant demands for food and energy.

Another example is Kenya, a country which has seen its avocado industry boom in recent years. It has become the world’s third-largest producer. Mulubrhan Amare, a research fellow at the International Food Policy Research Institute (IFPRI), said Kenya is still only exporting 10% of its total avocado production, 70% of which is produced by small-scale independent growers. Research conducted by the University of Sheffield in East Africa concluded that “Shade from PV panels reduces evapotranspiration – alleviating water stresses limiting crop growth – while powered equipment such as refrigeration can reduce post-harvest yield loss.”

“We see the biggest potential in avocado, due to its high compatibility to the model, the ability to implement it in large areas, and because of the high profitability and increasing demand,” said Noyman. However, he was quick to add that the list of suitable crops also includes lychees, plums, kiwis, passionfruit, mango, and edible grapes.

“Our business model is very attractive to farmers, and enables them to enhance their profitability, and that is why we do not encounter any setbacks from the farmers’ side,” Noyman continued. Willockx concurred: “If the shade gives an added value to the farmer (reduced need for irrigation water) without losing too much on the avocado weight and quality, I think that they will definitely look to agrivoltaics.”

Brett Heather, chief operating and technical officer at Alterra, a company that develops and manages agricultural land –including a planned 300-hectare avocado farm in Pemberton, Western Australia –told pv magazine that solar energy aligns well with the supply and demand needs of an avocado orchard. “Good business principles lead to good environmental outcomes,” Heather said.

At the moment, Alterra is only considering solar to power irrigation, not as an integrated system with the orchard itself. However, Heather noted that even in Australia, where land is not in short supply – the country is 353 times larger than Israel – “high-quality land assets in premium regions are hard to come by, and installing solar panels is going to impact the plantable area and yields at a development.”

 

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