The global food system needs to reduce its climate impact significantly. To illustrate, when considering the full value chain from production through to waste, agriculture worldwide contributes one-quarter of annual greenhouse gas emissions.
The EU aims to be climate-neutral by 2050 – an economy with net-zero greenhouse gas emissions. All parts of society and economic sectors will play a role – from the power sector to industry, mobility, buildings, and agriculture.
Possible advantages of vertical farming
To zoom in on the latter two, vertical farming is seen as a possible solution. In short, in a vertical farm crops grow in vertically stacked layers. It often incorporates controlled-environment agriculture, which aims to optimize plant growth, and soilless farming techniques such as hydroponics and aquaponics.
This method of farming is water-efficient, nutrient efficient, uses very little land, is highly productive, and typically does not require the use of herbicides or pesticides. In this TU Delft Story, researcher Andy Jenkins explains how we can make this type of agriculture a solution for the future.
With urban vertical farming not only can food be produced closer to consumers, but the heat produced by vertical farms can be captured and reused in urban energy grids, thus contributing to a circular built environment. Vertical farms can also benefit from the carbon dioxide produced by building occupants and rainwater harvesting from rooftops.
“As these farms grow, both in size and number, there is a growing interest for them to be sustainable. We still have a lot to learn about how to make this a reality, but I believe that the symbiotic integration of vertical farms in the built environment, including circular use of water, heat and CO2, has the potential to contribute to this.”
Dr Andy Jenkins | Architecture and the Built Environment, Climate Design and Sustainability | TU Delft
Half a football field with 20 layers in height
Referring to his experiences visiting vertical farms, Andy describes that when you step into a vertical farm for the first time, it is difficult not to be enamored by the blue, red, and white led lights, along with produce that looks healthy and vibrant.
The environment is comfortable, there is a pleasant breeze, and you can hear the trickling of water as nutrients flow around the system. As you look up, the multiple growing layers are impressive, and it is amazing to see just how much food can be grown in such a small footprint.
The vertical farming industry is now in a position where the technology is proven and the financial implications are clearer, which makes vertical farms more investible. As a result, we are now seeing a departure from small experimental farms to large, big-box farms that can occupy half a football field and be 15 to 20 growing layers in height.
“Currently, vertical farming requires a lot of energy to grow food, which is restricting it from achieving its full potential. Currently, the carbon footprint of the practice can be many times greater than greenhouse horticulture and open field farming due to the energy demands of multi-spectra LED lamps, mechanical ventilation, and cooling systems used to create carefully controlled and optimized growing conditions.”
Dr Andy Jenkins | Architecture and the Built Environment, Climate Design and Sustainability | TU Delft
Leveraging symbiotic relationships
Together with lighting specialists, breeding companies, growers, horticulture technology companies, architects, and food suppliers, Andy strives to make this type of vertical agriculture more energy efficient in the future by leveraging circular principles to share and reuse resources such as water, heat, and CO2. Andy’s goal is to reduce the energy use of vertical farms per kilogram of produce to the same as that of greenhouse horticulture, or better.
As part of his research, Andy among others explores ways in which the energy use of vertical farms can be reduced by first optimizing climate control systems and then exploring their integration in buildings and cities to capture, share, and reuse resources such as carbon dioxide, heat, rainwater, food, and nutrients.
This includes integrating vertical farms with a building’s electricity, heat, and resource systems as well as the broader integration with urban heat grids and micro electricity grids, making them a constituent component of future circular resource systems in cities.
It is hoped that by leveraging symbiotic relationships between vertical farming and the built environment, the reduction in energy use of vertical farms can be fast-tracked, without relying solely on the technical advancements of equipment within the farm.
“The symbiotic integration of vertical farms in the built environment has the potential to greatly decrease the environmental impact of the practice.”
Dr Andy Jenkins | Architecture and the Built Environment, Climate Design and Sustainability | TU Delft
Resource synergies, rather than direct energy savings
Andy is optimistic that the energy use of vertical farming can be reduced to that of greenhouse horticulture but stresses that this might not necessarily be at the farm gate. He expects that a large proportion of energy savings will be achieved through resource synergies, rather than direct energy savings at the farm.
One of the areas that shows the most promise is the capture and reuse of heat generated by a vertical farm. Approximately 50 percent of the energy used by LED lighting is converted into heat, which needs to be extracted to maintain optimum growing conditions. Andy does not expect that our research will deliver a huge reduction in the heat produced by vertical farms, as this is determined primarily by LED technologies, although some small gains may be achieved.
“Instead, the design strategies proposed will focus on capturing as much of this heat as possible to reuse it in neighborhood heat grids to reduce the energy use of host buildings and adjacent buildings alike.”
Dr Andy Jenkins | Architecture and the Built Environment, Climate Design and Sustainability | TU Delft
Instead, the design strategies proposed will focus on capturing as much of this heat as possible to reuse it in neighborhood heat grids to reduce the energy use of host buildings and adjacent buildings alike. It could be the case that vertical farms can only reduce their climate impacts significantly by being located within, or close to, cities, due to the immediate access to other resource flows. This could include vertical farms in domestic settings, rooftop, atrium, or basement vertical farms in larger buildings, and large-scale peri-urban vertical farms on the periphery of cities.
Vertical farming in the future
So what does the future of vertical farming in cities look like? Andy indicates that vertical farms can be constructed much closer to where demands are highest, which can greatly reduce the food miles of some foods. Consequently, these crops do not need to be frozen or packaged as they are being sold quickly over short distances, which not only saves energy but can lead to improvements in nutrition by creating short supply chains.
“The widespread adoption of vertical farms in cities can create jobs and reconnect citizens with farmers and food production, and the heat produced by vertical farms can be captured and reused in urban energy grids, making the farms part of a circular built environment. For me, there is no question that vertical farming is here to stay.”
Dr Andy Jenkins | Architecture and the Built Environment, Climate Design and Sustainability | TU Delft
Source: This 'Story of Science' is derived from the TU Delft Stories page. Read more TU Delft stories here >>
Andy Jenkins works alongside TU Delft colleagues Tess Blom and Andy van den Dobbelsteen - Principal Investigator at AMS Institute. This TU Delft story is linked to the Sky High – Project C2, which is part of the NWO Sky High research programme, aimed at improving the productivity, predictability, and replicability of vertical farming.