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Can farmers harvest food and sunshine at the same time?
That's a question some Albertans might be asking themselves after driving past a large solar array on farmland. If we use land to produce clean energy, does that mean less land for food?
Not necessarily. If implemented correctly, farmers can use Agri-PV to grow food and generate electricity on the same piece of land. The city of Bon Accord used sheep to mow the grass beneath its solar array from 2021 to 2022.
“It was great to have sheep there,” said Jodi Brown, city CAO, as it saved the city money on mowing and gave the sheep grass to eat.
Janna Greir of Solar Sheep Inc. has been using sheep to mow the grass at the Strathmore Solar facility for about three years. The facility's owners (Capital Power) save money on mowing while making money for their services and getting more land to raise more sheep.
“It has allowed us to grow our business,” Greir said.
Boost plants
Agrivoltaics is the use of solar panels to increase crop yields, said Joshua Pearce, a solar technology researcher at Western University in Ontario and co-founder of Agrivoltaics Canada. To do this, you calculate how much sun, wind, heat and water a plant needs and use panels as fences and shade to create the ideal growing conditions.
Pearce said researchers have found that properly designed on-farm solar systems can significantly improve yields in crops such as basil, broccoli, celery, corn, lettuce, pasture grass, potatoes, spinach and wheat. A 2018 study of a solar farm in Oregon found that grass beneath panels was 90 percent more abundant and 328 percent more water efficient than unprotected grass.
“You can get huge increases in yield,” Pearce said.
“The combination of crops and solar energy provides farmers with financial security in the form of ongoing income from electricity production or lease payments from the plant owner,” said Mikhail Ivanchikov of Dandelion Renewables (builder of the Bon Accord plant). Solar panels can also serve as windbreaks to reduce soil erosion and improve land value.
Be careful ahead
Solar and sheep don't always work. John Wurz, chief of the Morinville Hutterite Colony, said he pulled his sheep from the Bon Accord facility in 2022 after a protection dog went missing and about half the flock died.
“For me it was more trouble than anything else,” he said of the sheep in the flock, as he had to go out of his way to check on the sheep.
Pearce said it is not yet clear whether agri-PV will work on every crop. Most of the research on this has been conducted outside Canada, and there is still much work to be done to determine whether the benefits can be realized in this country. (His team is currently conducting research in this area.)
Agri-PV with sheep also takes work, said Greir. You need insurance for your sheep, enough staff and protection dogs to protect them, and the right mix of grass under the panels to ensure proper nutrition. To ensure that the sheep eat all the grass and not just the plants they like, you also need to use rotational grazing (where the animals intensively graze one region before moving to another).
Farmers should tailor solar farm designs to their crops, Pearce said. Fixed panels might be suitable for shade-loving lettuce, for example, while wheat might need long, widely spaced walls of panels (ideally ones that can rotate to follow the sun) to give combines freedom of movement.
Pearce said agri-PV has huge potential in Alberta. A study he led found that Alberta could get almost all of its electricity from carbon-free sources if it built agricultural solar on about 1.4 percent of its farmland.
“Nobody wants to see good agricultural land paved over,” Pearce said, as it would drive up food prices.
“I don’t think we should operate normal solar farms anymore. We should do everything as agri-PV.”
