Lighting Technologies

One of the important components of successful vertical farming is sound lighting. Available LED technologies provide only 28% efficiency, an efficiency rate that should be increased to about 50%-60%, at a minimum, to make indoor farming methods cost-effective [37]. Fortunately, experimental developments in LEDs have reached that mark [37,38]. Dutch lighting engineers at Philips have produced LEDs with 68% efficiency. Such an increase in lighting efficiency will dramatically cut costs. Also, a Dutch-based group called PlantLab has recently invented a lighting technology that could help to grow food with a small footprint. According to Michael Levenston, “This invention replaces sunlight with LEDs that produce the optimal wavelength of light for plant growth. Contrary to the sun, traditional assimilation lighting, and TL lighting LED only omits one color of light. No energy is wasted with light spectra that are not used ... by the plant” [38]. As such, the new lighting technology provides the correct lighting colors plants need for photosynthesis— blue, red, and infrared light.

Furthermore, new “induction” lighting technology simulates the color spectrum of sunlight to foster the growth of vegetables and fruits. “The light uses an electro-magnet to excite argon gas as its light source, instead of a filament. For this reason, [it] uses much less energy and can last up to 100,000 hours, twice as long as an LED light” [39]. It also generates more heat than LED light but less than an incandescent bulb. Therefore, the lights create enough heat for growing plants without wasting energy to heat the entire building. Moreover, the light units are calibrated to create an “ideal” microenvironment by producing high-quality lighting that is similar to daylight. These units are also long lasting, with a life span of about one decade, and are sold at affordable prices.

Farming Operation

Researchers predict that farming operations will be fully automated in the near future. For example, monitoring systems will be widely implemented (in the form of sensors near each plant bed) to detect a plant’s need for water, nutrients, and other requirements for optimal growth and development. Sensors can also warn farmers by signaling the presence of harmful bacteria, viruses, or other microorganisms that cause disease. Also, a gas chromatograph technology will be able to analyze fla- vonoid levels accurately, providing the optimal time for harvesting. These specific technologies are not totally new. Their development has been ongoing and will likely proliferate in the near future [39].

Farming from Afar

One of the promising ideas under development is “farming from afar.” The cell phone, its software, and apps will ultimately handle much of the day-to-day tending of crops, and vertical farmers will be able to manage multiple farms remotely. New apps will allow farm managers to adjust “nutrient levels and soil pH balance from a smartphone or tablet, and sound alarms if, say, a water pump fails on a vertical-growing system. ... So if I’m over in London, where we’re looking for a future vertical farm site to serve restaurants, I’ll still be able to adjust the process in Michigan or Pennsylvania,” as Paul Marks explained [40]. Farming from afar will drastically reduce operational costs by reducing labor and will provide considerable convenience, flexibility, and efficiency in managing farms. Further, by engaging new information technology and working with new online applications, farming could become an exciting and fun activity.

"Closed-Loop Agricultural" Ecosystems

“Closed-loop agricultural” ecosystems intend to mimic natural ecosystems that treat waste as a resource. Similar to aquaponics, the waste of one part of the system becomes the nutrients for the other. The closed-loop system recycles and reuses nearly every element of the farming process—dirty water, sewage, and nutrients. Food waste can also be converted to compost. In a closed-loop system, everything remains in the system, leading to a zero-waste outcome. This results not only in drastic decreases in waste but also in the creation of energy and other by-products such as bedding and potting soil.

Anaerobic Digester

An anaerobic digester is a biogas recovery system that converts food waste into biogas to produce power and heat [41]. The Plant, a vertical farm in Chicago, has employed an anaerobic digester that captures the methane from 27 tons of daily food waste to produce electricity and heat. Figure 4.3 illustrates how The Plant has integrated an anaerobic digester in its employed close-loop system (also see Section 3.2 on The Plant). Similarly, Great Northern Hydroponics (GNH) in Quebec, Canada, has employed a cogeneration machine that reduces its heating costs and reliance on fossil fuels. GNH’s power production has increased such that it is capable of selling electricity back to the Ontario Power Authority, decreasing the province’s dependence on fossil fuels.

The main features of the closed-loop systems are as follows:

  • • At the heart of the system is an anaerobic digester that turns organic materials into biogas, which is piped into turbine generator to make electricity for plant grow light.
  • • The plants make oxygen to the Kombucha tea brew'ery, and Kombucha tea brewery makes CO, to the plant.
  • • Waste from the fish feeds the plants and the plants clean the water for the fish.
  • • More fish waste goes to the digester along w'ith plants’ waste, waste from outside sources, and spent grain from the brewery.
  • • Spent barley from the brew'ery feeds the fish.
  • • Sludge from the digester that becomes algae duckw'eed also feeds the fish.
An illustration of an integrated food production through a closed-loop system. (Adapted from AgSTAR

FIGURE 4.3 An illustration of an integrated food production through a closed-loop system. (Adapted from AgSTAR: Biogas Recovery in the Agriculture Sector, United States Environmental Protection Agency, Available online: https://www.epa.gov/agstar, accessed on July 15, 2017.)

  • • Along electricity, the turbine makes steam that is piped to the commercial kitchen, brewery, and the entire building for heating and cooling.
  • • Therefore, the kitchen produces Kombucha tea, fresh vegetables, fish, beer, and food, all with no waste.

Renewable Energy

Some vertical farms have implemented, and others have proposed, employing w'ind turbines and photovoltaic panels to supply power. Other systems, such as thermal systems that collect solar heat and warehouse refrigeration exhaust, are also under consideration.

Integration within City Infrastructure

Future proposals, for example by Plantagon, envision the integration of vertical farms with the city symbiotically. The proposal envisions that the vertical farm will collect organic waste, manure, C02, and excess heat from plants and factories and transform these into biogas for heating and cooling. In this way, the vertical farm not only could grow food but also could help to develop sustainable solutions for better energy, heat, waste, and water use (Figure 4.4).

The proposed vertical farm in the downtown of Linkoping, south of the capital Stockholm in Sweden by Plantagon provides an industrial symbiotic system

FIGURE 4.4 The proposed vertical farm in the downtown of Linkoping, south of the capital Stockholm in Sweden by Plantagon provides an industrial symbiotic system. Partnership will be established among Plantagon, a local energy company, and a local biogas plant. The greenhouse gets district heating from the power plant that runs through a major road. It gets excess heat and carbon dioxide from the biogas plant, and the leftover from the greenhouse goes into the biogas digestor. (Adapted from Advantages of Vertical Farming, Vertical Fanning Systems, Available online: http://www.verticalfarms.com.au/advantages-vertical-farming, accessed on July 15, 2017.)

Redefining Vertical Farms

The aforementioned technologies are redefining the vertical farm as “a revolutionary approach to producing high quantities of nutritious and quality fresh food all year round, without relying on skilled labor, favorable weather, high soil fertility or high water usage” [24]. These new systems add advantages to vertical farming, summarized in Table 4.2.

Advantages of High-Tech Vertical Farming Systems

TABLE 4.2

1. Reliable harvests

Controlled indoor environments are independent of outside w'eather conditions and would provide consistent and reliable growing cycles to meet delivery schedules and supply contracts.

2. Minimum overheads

Production overheads would decrease by 30%.

Low energy usage

The use of high-efficiency LED lighting technology ensures minimum power use for maximum plant growth. Computer management of photosynthetic wavelengths, in harmony with phase of crop growth, further minimizes energy use while ensuring optimized crop yields.

Low labor costs

Fully automated growing systems with automatic SMS text messaging would require manual labor only for on-site planting, harvesting, and packaging.

Low water usage

Vertical farms w ould use around 10% of the water required for traditional open field farming.

Reduced washing and processing

Vertical farms would employ strict bio-security procedures to eliminate pests and diseases.

Reduced transport costs

Positioning of facilities close to the point of sale would dramatically decrease travel times, reducing refrigeration, storage, and transport costs in the process.

3. Increased grow ing areas

Vertical farms would supply nearly ten times more growing area than traditional farms.

4. Maximum crop yield

Irrespective of external conditions, vertical farms can provide more crop rotations per year than open field agriculture and other farming practices. Crop cycles are also faster because of controlled temperature, humidity, light, etc.

5. Wide range of crops

The vertical farm would provide a wide range of crops.

6. Fully integrated technology

The vertical farm would be fully monitored, controlled, and automated.

Optimum air quality

The temperature, carbon dioxide (CO,), and humidity levels of the vertical farm would be optimized at all times.

Optimum nutrient and mineral quality

The vertical farm would use especially formulated, biologically active nutrients in all crop cycles, providing organic minerals and enzymes to ensure healthy plant growth.

Optimum water quality

All fresh water’s contaminants would be removed before entering the vertical farm.

Optimum light quality

High-intensity low'-energy LED lighting would be specifically developed and used for maximum growth rates, high reliability, and cost-effective operations.

Source: Advantages of Vertical Farming, Vertical Farming Systems, Available online: http://www. verticalfarms.com.au/advantages-vertical-farming, accessed on July 15, 2017.

 
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