The Benefits and Challenges of Underground Farming

Underground farming comes with big promises of helping the world develop a sustainable and scalable method of producing its food. It also comes with its own challenges.

Underground Farming, as the name may suggest, is the practice of growing food underground. This agricultural activity takes advantage of CEA technologies (Controlled Environment Agriculture) and aims at creating stable underground environments where food is grown in constant, predictable and sustainable ways.

Some companies have already started to explore this opportunity with successful results. For example Growing Underground, a UK based company, is growing food underground in World War II bomb shelters.  Another example is Cycloponics, a startup in France which turns abandoned urban underground spaces such as parkings and bunkers into farms. Even academics in the UK are also considering transforming the large number of old coal mines in underground farms. And of course there’s our team which is working on the development of underground farming systems, which we call GreenForges.

So as you see underground farming is a recent and important trend, but why? Because of it’s potential and the benefits that it brings…

Benefits

Underground farms take advantage of controlled environment agriculture technology, which comes with considerable pros compared to traditional agriculture. It produces healthier and tastier food, no chemical runoffs, almost no waste, lower water consumption, year-round production and even more. But right now what we’ll focus on is the advantages that are unique to underground farms:

Enables Farming in Hostile Environments

Obviously when going under a certain depth the weather and environmental conditions of the surface have no effect on the growing environment. Instead the important variables are related to the geological context along with underground water levels. So with this in mind, we believe that it’s possible to build large and productive farms in hostile environments such as deserts, tundra and even mountainous areas.  

Higher yield with less Space

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Although we’re exploring all kinds of configurations for GreenForges, one of the most interesting is the vertical shafts setup because they are really hard to beat when looking at the ratio of yield and space required in the surface.

For example the picture on the right here represents a room with 24 GreenForges of more than can go to hundreds of feet deep. To get as much production, even when it comes to the most modern plant factories, it would require a room orders of magnitude bigger.

And so when it comes to yield per unit of surface used compared to pretty much all the other setups out there. The only way to do better is to have the farms located completely underground with no direct access from the surface.

Increases Urban Farming Capacity

Normal urban vertical farming has a capacity problem…

It has been estimated that even if cities were to build rooftop greenhouses on every capable buildings and fill the parking spots with growing containers - it would only be able to reach around 5% of the crop requirements of the city. Growing in cities is highly limited because there is just not that much empty lots or parking space to make a big dent with growing containers. Rooftop greenhouses, on the other hand, require buildings that have very large flat roofs and whom are strong enough structurally, most residential and commercial buildings simply don’t have that.

GreenForges have a big advantage here, not just because they require less surface space than the other solutions, but also because they can be integrated with almost any new buildings, unlike rooftop greenhouses.

Lowers Heating Costs for Building Above

Even the most efficient LED lights generate waste heat, which means that they heat up the farm, and for most modern indoor vertical farms that’s a major issue because not only energy is lost through lighting, but it’s also required to cool down the farm. A double whammy.

So for GreenForges we aim at minimizing that waste of energy as much as possible, and we’re working on ways to recycle the waste heat in order to help heat the building above and reduce its energy.

Geothermal Synergy

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And for that we have a big edge.. the ability to cool down the greenforges thanks to geothermal energy.

This is significant because geothermal is one of the most energy efficient ways you can keep the temperature of an environment stable. It requires significantly less energy than the alternatives. They aren’t as widespread because they require drilling or excavating; which has a cost. But in the case of GreenForges we already have that machinery on site so it’s a no-brainer.

That synergy allows our underground farming systems to keep a stable environment for the farm at a lesser energy cost than surface indoor farms.  

Surface Regeneration

Normally every time a new residential or commercial plot of land is developed in a city, it serves as shelter or workplace, often at the cost of existing farm land which will never go back to producing food.
But if we were to integrate GreenForges within theses new developments, the plot of land could serve both purposes - and help bring about some of the calories required by it’s inhabitants. Removing much of the need to clear land somewhere to make up for the lost agriculture capacity.

Overall the more agriculture production we move underground, the less space required on the surface of the Earth. Allowing for the natural restoration of the land on the surface. It’s one of the most exciting and encouraging benefit of our underground farming systems and pretty much the main reason why we’re doing this.

Let’s have a look at the main challenges to overcome…

Challenges

In addition to the regular challenges of farming, these are several other issues to consider in the context of underground farming, here’s a few of them:

Economics

Our underground farming systems make use of complex and new technologies which are capital intensive compared to traditional farming. Just like most of the indoor vertical farms, the costs of building and operating them is a challenge and limits the type of crops that are economically viable.

It’s the reason why we are so focused on making efficient use of energy and labor; they are the main operational costs. And it’s also why we are focused on richer urban areas first, especially high end residential and commercial developments. This allows us to enter at the high end of the market and then work on yields, labor and energy efficiency in order to lower prices overall and broaden the markets we can access.

Geology

Surface conditions do not affect us but underground ones sure do. Things like soil composition and the ground water levels will dictate where we can put farms (or not).

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Along with that the cost of digging varies from one region to another and gets more expensive the deeper we go, limiting how deep we can make the farms. Because of this for our first farms we are planning depths which can be easily reached using regular excavation equipment used across the world in construction. We refer to this as shallow GreenForges.

We’re also exploring options to go much deeper but the only chance theses have to come into play is later once we’re scaled up and our prices much lower.

Energy Source

Just like in Vertical Farming, the energy demand is a constraint. Replacing the sun is not an easy task. Although Controlled Environment Agriculture  uses less resources overall it requires more energy compared to traditional agriculture.

Obviously this impacts the economics as mentioned above but more importantly the type of energy generation fuelling the grid has the greatest impact on the greenhouse gas emissions of the underground farms. Based on our research and calculations, GreenForges have a positive impact on GHG when the source of energy is renewable. Meaning they are lower than  traditional agriculture.

But the contrary is the case when the power source comes from burning fossil fuels - greatly limiting the cities and rural areas where it makes sense to install GreenForges.

Education

Indoor farming is a new thing and consumers sometimes have a negative first reaction. Mostly because they get the feeling that food grown in soil and with the sun is healthier and better. But this isn’t necessarily the case.

In reality indoor food can be much healthier for us, by controlling the nutrient intakes of the crops and not using pesticides, herbicides and fungicides. At the same time greatly reduce our impact on the environment - but communicating this to a broad number of people in quick and intuitive way isn’t easy.

Also in terms of labor the learning curve to operate indoor vertical farms is relatively steep compared to traditional farming. And for underground farming systems it’s even higher. From horticultural to mechanical engineering and machine learning expertise, different set of skills are required to successfully make the technology work, adding up to the challenge of staffing the farms.

This pretty much rounds up the benefits and challenges for underground farms, if you’d like to learn more about underground farming technology and/or our vision please see the links below, and thanks for reading!