INTERVIEW
Going underground
An interview with the minds behind GreenForges subsurface farms
As part of our feature on their underground farms I caught up with two key members of GreenForges staff. Chief Technology Officer, Jamil Madanat and Chief Product Officer, Andrew Stride gave me the full lowdown on everything happening below the surface.
Where did the idea for underground farming come from?
Jamil: Our founder, Philippe Labrie, used to work in building development but he’s always had an interest in the world of farming. One day he was looking outside and saw a water well and thought, why can’t we do the same thing with food? By going as deep as a well you can save lots of land space. And his experience in the building industry also led to the idea of connecting this with the foundations of buildings. That’s where the dream started of a symbiotic system where plants feed oxygen to the building and take the carbon dioxide to feed on themselves.
How did it progress from there to becoming a business?
Jamil: I carried out some feasibility studies initially to see if the idea was viable. The results were very promising in terms of energy consumption compared to other vertical farms on the surface. So, once we knew it was something that could work commercially, we started building prototypes and running physical testing.
Can you tell me about how you can grow plants underground? How do you ensure they have the right temperature and enough water, oxygen, light, and CO2?
Andrew: We’ve designed individual ‘forges’ that contain everything the plants need to grow. Each forge houses what is largely a closed system - fresh air has to be brought in but all of the water is continuously recycled around the system. We’re also looking at reusing the water from the dehumidification process to minimize waste.
We had custom designed LED lighting systems built specifically for us to deliver optimum light to the plants. They’re one and a half meters tall with nine LED bars on each. They have adjustable dimming that gives us the flexibility to grow crops that require different amounts of shade and light.
We also have a full HVAC solution providing complete temperature and humidity control so the plants are never too hot or too cold.
It must be a very complex system. How did you optimize the design to ensure successful plant growth?
Jamil: The engineers at Maya HTT have been vital to the project. Plants are very sensitive to humidity and temperature so it simply wouldn’t work without an HVAC system that allows us to fine tune the conditions. They helped design simulations that answer questions like how much the soil will absorb the heat generated by the lights, how will condensation affect the plants, how does the type of soil affect humidity and at what depth does it change. The temperature stabilizes further down but you need to understand the range all the way through the length of the farm. It’s very complex physics to be able to simulate all of this and we couldn’t have done it without Simcenter and Maya HTT.
You also need to consider how the plant’s needs change as they grow. As time goes on, they generate much more humidity so there’s more water to be extracted. Simulation allowed us to quickly go through many iterations rather than waiting for plants to physically grow. So, we could change various parameters and come up with the ideal solution much faster. For instance, the first design we tried had a 40-inch diameter and was 100 feet deep. The simulations quickly showed this wasn’t going to work so we reduced the depth and widened the diameter and got much better results.
As you said, the main benefit is the amount of space saved on the surface, but are there other advantages to underground farming?
Andrew: Yes, the most obvious thing is the amount of surface space you can save, but temperature and climate control is also a big advantage. Once you dig down to around 20 feet the temperature is pretty much the same all year round. Regions that can’t support surface farms due to being too hot or too cold could be suitable for underground farms as we’re developing a completely controlled environment that will work anywhere. This also means that we’re not reliant on weather at all as everything is happening below the surface. We don’t need to worry about overnight frost or if it’s going to be sunny enough that week as we can guarantee all the conditions the plants are growing in.
Climate change is a big concern for farming, but our system will help combat this as we can keep crops at the ideal temperature. We could even expedite harvest cycles as we don’t have to rely on the seasons above ground.
We have much more control over pests too. We can’t completely eliminate them as there are still times when the cover has to be opened. But this is only during seeding and harvesting – the rest of the time we have total control over all the air going in and out, so pests are really minimized compared to surface farms.
Speaking of harvesting, it must be very different to normal farms. How does it work with an underground farm?
Andrew: Yes, harvesting is very different. There’s no need for all the tractors and diggers that surface farms use so there will be a significant reduction in the carbon footprint those create. We’ve designed a fully automated extraction system that brings the modules up to the surface, puts them onto an overhead conveyor belt within the facility, and takes them to a harvesting station. Then the plants can be harvested manually by people or, depending on the customer’s needs this process can also be automated. Then when it comes to seeding, we germinate plants in a separate smaller system and then put them into the modules and the automated system puts them back into the farm.
It sounds like all the pieces are in place. When can we expect to see underground farms in operation?
Andrew: We have a prototype currently running where we’re testing all the lighting, cooling, and water supply, and we have another larger prototype currently being built to test that the extraction system works correctly. We’re hoping to have a live pilot up and running soon, but it’s a case of finding the right site with the right investment. Once we have the site secured and the funding in place, which is a big challenge, we should have the facility up and running within six to nine months.
Fascinating insights, thanks so much to Jamil and Andrew for your time. To find out more about GreenForges, check out our cover feature or head to www.greenforges.com.
“It’s very complex physics to be able to simulate all of this and we couldn’t have done it without Simcenter and Maya HTT.”
Jamil Madanat