Climate-Resilient, Solar-Powered Farming

It looks like a fibreglass Quonset hut, plunked near solar panels in a strawberry patch. But peek inside the Agrotunnel — a high-tech vertical farm near London, Ont. — and you’ll find its walls alive with fragrant, bright-red strawberries, ripening inside a temperature-controlled, solar-powered environment. 

Welcome to “agrivoltaics,” the integration of solar energy with conventional and high-tech farming. The result is “climate-resilient” food that’s grown closer to consumers, says Prof. Joshua Pearce, lead researcher in this solar-powered food production project at London’s Western University. “Just give me the land, and you can have net-zero, locally-produced food almost anywhere,” he adds.

The concept has already earned a $1 million grant from the Weston Family Foundation’s Homegrown Innovation Challenge. (The Foundation specified berries as the experimental crop.) Now Pearce’s students are using the cash to put the prototype through its paces. 

Outside, where berries grow beneath solar arrays, “we get the normal yield,” Pearce says. But on the inside, where eight vertical “grow walls” hold 720 plants on each face, “we get this insane growth.” In terms of footprint, “a thousand square feet [0.2 of an acre] of plants can produce the equivalent of 10 acres of land outside.”

The insulated Agrotunnel uses LEDs that mimic daylight, water pumps to circulate nutrients and water, and heat pumps and dehumidifiers to maintain a temperature of about 20 degrees C and relative humidity of about 55%. Inside, “it’s always a beautiful spring day” says Kim Parker, president of Food Security Structures Canada, the Agrotunnel’s supplier and a partner in the research. 

This kind of production can come with a big energy bill. Western cuts costs by coupling the Agrotunnel’s efficient design with solar energy. Using solar panels to power the Agrotunnels, Pearce estimates the unit can operate as far north as Edmonton on the electricity used to power about seven homes. “It’s technically a greenhouse, and you can pull it into a parking lot and start using it,” he says. “For power, you need three to five times as much land as the building occupies for the solar panels.”

Researchers are reworking panel technology to produce semi-transparent units allowing more light for crop growth. “We’ve had good success with modules allowing up to 45% of the light through,” Pearce says. As a bonus, plants growing beneath the solar panels suffer less heat and drought stress than those grown in an open field, particularly in hot, dry locations. 

Parker adds this research will benefit the entire sector. “Controlled Environment Agriculture is relatively new, and it has been a challenge getting benchmarks for things like energy consumption and water usage,” she says. With the help of Western and support from the Weston Foundation, “what we’re hoping to do is not just set benchmarks for the industry but have them backed up by third-party academic research.”

The next step is to try out the units in commercial settings, including farms, and possibly restaurants and grocery stores. Parker hopes the agrivoltaic package could eventually be marketed to growers for less than $500,000. 

But first, Pearce cautions, “we want to make sure this is completely ready for showtime.” 

Want more? Read about a National Park in Wales that is Betting on Farming.