Solar power may be the cheapest form of energy available to power-hungry economies, according to the International Energy Agency, but that doesn’t mean it doesn’t have its drawbacks. There’s the solar industry’s dependence primarily on foreign supply chains, the inherent intermittency of an energy source that’s available only during the day, and Canada’s inherent disadvantage of being at a northern, less sun-baked latitude.
Some or all of those problems might be ameliorated with a combination of policy and new technologies, but we’d still be left with one of solar’s most fundamental drawbacks: it’s land-hungry. Sunlight is free, but it’s spread diffusely over the surface of the Earth, and large solar farms can conflict with other land uses — most critically, farming. During the heyday of green-energy policies under the previous Liberal government, Queen’s Park nevertheless adopted policies restricting the expansion of solar power on the farmlands the province most wanted to preserve.
A researcher at Western University, in London, suggests that might have been a mistake, but not because we should trade food farms for the solar variety. Rather, Joshua Pearce says we can have our cake (or at least our wheat, corn, and potatoes) and eat it, too.
“For solar, you need massive areas. For a single building, maybe you can power it with panels on the rooftop, but beyond that you start to run out of space,” says Pearce, the John M. Thompson Chair in Information Technology and Innovation at the Thompson Centre for Engineering Leadership & Innovation. “We’re talking gigawatts of the potential. What we need to transform Canada is huge that means an enormous amount of land area. But we farm quite a bit.”
Agrivoltaics is a relatively new field that involves combining solar photovoltaic panels in agricultural operations. Solar panels are erected in farm fields, spaced apart such that farming machinery can navigate around them. (Solar panels need to be separated by some distance anyway in order to avoid casting shadows on one another.)
“A lot of us got into photovoltaics specifically to solve environmental problems,” Pearce says. “The idea of making food cost more was really a problem.”
While intuition would suggest that intercepting the sunlight aimed at growing crops would reduce the farmer’s yield, in at least some cases the opposite seems to be true: Pearce says that numerous crops do better in the partial shade provided by solar panels.
“Essentially any leafy green, any crop where you want to eat the leaves, does better under agrivoltaics because the partial shade has the plant put more energy into growing the leaf so it can reach the sun,” Pearce says. Some of his previous research estimated that, with just the land dedicated to lettuce farming in the United States, there’d be room to build 40 to 70 gigawatts of solar power.
Leafy greens are a relatively small portion of Ontario’s agricultural output, but agrivoltaics aren’t suitable just for the small potatoes of the market: Pearce’s list of crops amenable to sharing space with solar panels includes actual potatoes, as well as corn, wheat, and tomatoes.
Given the sheer volume of land dedicated to agriculture in Canada and elsewhere — agriculture is the single biggest land use on the planet — agrivoltaics could potentially offer an enormous well of energy that could be drawn upon without creating conflicts between other existing land uses.
How enormous? Pearce and his colleagues estimate that, with 0.5 per cent of the land used for agriculture in Ontario, the province could retire its remaining fossil-fuelled power plants and run an entirely clean electricity grid (a job that would be made easier by the fact that the Ontario’s grid is already very clean thanks to hydroelectric and nuclear plants). For Canada overall, 1 per cent would do it.
“If you get a little fancier: say you want to electrify all home heating, electrify all the vehicles,” Pearce adds. “That’s about 5 per cent of all agricultural land, while increasing agricultural output.”
One catch is that most of the data Pearce relies on in his estimates comes from test plots in other countries. He’s trying to change that by using a greenhouse at Western University to simulate normal Canadian weather and soil combinations to see how agrivoltaics perform under Canadian conditions.
The current obstacle to expanding agrivoltaics in Ontario isn’t so much the Ford government’s hostility to renewable electricity — which has been softening in recent months — as it is the legacy of decisions made by the Liberal government under Dalton McGuinty when it was actively supporting renewables: worried about the potential destruction of prime farmland, it prohibited the construction of solar-power projects on class 1 and 2 farmland; the rule was later extended to class 3 farmland and organic soils.
Pearce says those rules should now be revisited so that Ontario can take advantage of the opportunity that agrivoltaics represents.
“In Ontario, where it makes the most sense to do agrivoltaics, it’s not allowed,” he says. “The original rules were good ones — it doesn’t make sense to dig up your best farmland and pour concrete all over it for a solar farm. But now we know better.”
Pearce says there’s one part of Ontario in particular where abundant farmland could be used to feed electricity to a power-hungry market while also protecting those green spaces for the future: the Greenbelt around the GTA. Weaving the farms that remain in the Greenbelt into the region’s power system would both protect those lands for the longer-term and constrain urban sprawl.
Contacted by TVO Today, the Ministry of Energy didn’t shut the door entirely on exploring Ontario’s agrivoltaic potential, saying that the government has asked the Independent Electricity System Operator to reassess the current rules as part of the latest round of renewables procurement.
“Our government knows that agricultural lands are critical to Ontario’s economy and to feed our growing population. That’s why there are currently guidelines in place regarding ground-mounted solar projects on farmland in Ontario, including that they be secondary to the agricultural use, limited in area and compatible with surrounding agricultural operations,” a spokesperson for Energy Minister Todd Smith, told TVO Today via email. They also reiterated that all new renewable-energy projects in Ontario will still require support from the local municipality.
Whatever the opportunity for agrivoltaics in Ontario, it’s likely to be a while before policies change to accommodate it. But, in the future, it might be common to see farmers’ fields hosting solar panels as well as tractors, with the countryside both feeding and powering the province’s cities.
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