Vertical Farms: Bringing Agriculture to Cities

Self-sufficiency is a defining characteristic of urban circular economies, next to extreme forms of recycling and the repurposing of assets and consumables. While urban self-sufficiency is most often referred to in terms of energy and other utilities like clean water, food is a critical resource that cities typically almost entirely source from either the surrounding countryside or faraway countries. Farming land can occupy as little as 1% of a city’s land surface due to its inherent financial competitive disadvantage compared to other uses of the land. Access to locally generated food resources is an important missing piece, from both circular economy and resilience perspectives, with climate change-induced threats to traditional agriculture—in the form of endemic flooding, for example—globally becoming a real concern. In an increasingly global urban context, the issue of food stability and sustainability is a critical one. Moreover, local production allows for a reduction international transport, thereby reducing carbon emissions significantly. Finally, direct access to fresh food produce is a key component of cities’ preventive healthcare strategies, another critical smart city objective aimed at saving healthcare costs.

While vertical farming essentially transfers the traditional growing of eatable plants from the earth to artificial substrates stacked vertically to virtually unlimited heights (the equivalent of habitable skyscrapers), it is also possible to create food artificially through chemical processes akin to traditional manufacturing.

Unsurprisingly, Singapore is the leading city in terms of exploring vertical farm technology. As a city state, it has no access to countryside farmland at all—93% of all produce is imported.  Having initially experimented with rooftop gardens and farm towers, Singapore is now exploring more advanced urban farming techniques through the pioneering Sustenir Agriculture venture’s Controlled-Environment Agriculture (CEA). This allows 95% less water to be used compared to traditional farming while at the same time using less energy. The word’s first commercial vertical farm was opened in 2012.

Food plants are now grown without sun light and soil. LED lighting is used as a replacement for sunlight and seed ingestion and germination is fully automated. In optimized growing rooms, air temperature, humidity, CO2 percentage, light duration and wavelength, and the percentage of oxygen in the water are all tightly controlled. Beyond ensuring maximum quality, this even allows the very taste of the plant-based food produced to be controlled to cater to local tastes. Moreover, growing food indoors avoids the need to use insecticides and/or pesticides.

Singapore’s Food Innovation and Resource Center explores artificial, 3D printed food creation tailored to the caloric and nutritional needs of its population including personalization based on lifestyle and health conditions and even individual metrics derived from wearable sensors. Artificial Intelligence (AI)-based health issue prediction allows preventive action in terms of producing food with the right nutritional value, minerals, vitamins, and other ingredients, very much closing the loop between food generation and consumption on one hand and healthcare on the other hand. 

While vertical farming is an example of the growing importance of biotech for smart cities, it can only be efficiently implemented and operationally managed through a range of IoT connectivity and analytics technologies. Remote monitoring and control, robotic automation of the delivery of water and nutrients, and harvesting and packaging are just some examples of use cases for IoT technologies.  A vertical farm can very much be seen as a combination of automated manufacturing technologies based on Industry 4.0 and advanced commercial building systems.

Despite the use of advanced IoT technologies, reaching profitability for vertical farms remains problematic due to a wide range of factors including the high cost of urban real estate and the need for artificial heating/cooling and lighting. Additionally, these urban industrial farms can add to pollution in cities. To address these issues, solutions like carbon neutral operations based on renewable energy and the use of abandoned buildings, tunnels, or other existing urban facilities need to be considered. Alternatively, very tall buildings to increase the yield per square foot can be envisioned.

On the other hand, vertical farms need to be considered and understood from an urban resilience perspective, which comes at a cost, similar to other projects such as the building of sea walls as protection against flooding. Cities will need to set aside real estate and other resources, either as back-up or as operational facilities, to ensure sufficient vertical farm capacity in the face of any expected or unexpected rural farming output shortages.