Developing an integrative framework for entrepreneurs to assess the ability
of cities in developing countries to accommodate a hydroponic vertical farm
A Case Study on Cape Town, South Africa.
Abstract
Hydroponic vertical farming techniques have increasingly been recognised by pioneering bodies of research, as being able to contribute to food security in the urban environment, by reducing the amount of inputs needed such as land, energy, water and nutrients, whilst increasing yields. However limited research is available on the topic and these techniques require certain infrastructure to be in place, which can be problematic in cities in developing countries. This paper therefore, seeks to construct a framework for entrepreneurs to assess the availability of the fundamental requirements for operating a hydroponic vertical farm in cities in developing countries. The four criteria that are assessed in this framework are the availability of water, energy, nutrients and local diet compatibility and the suitability of the political environment. The framework will be applied in a case study on the city of Cape Town, South Africa. Cape Town fails at three of the four checkpoints and receives a negative investment advice.
Jibbe Bertholet 10786597 Celena van der Noll 11040068 Aimée Kampschöer 10803513 Chanika Schraa 10756108 Teachers: Emma Daniëls and Tamara Jonkman
Introduction
Rapid worldwide urbanization has reshaped civilization over the past century, as the number of people living in cities now exceeds the number of people in the rural areas (Grimm, Foster, Groffman, et al., 2008) and future population growth is expected to take place primarily in cities (Grewal & Grewal, 2012). The shift in dynamics of the urban environment increasingly requires cities to import more resources for sustaining the lives and well-being of the urban population. It also demands finding adequate solutions to dispose of the waste created, which causes the ecological footprints of the growing cities to far exceed the area of the city itself (Grimm, Faeth, Golubiewski, et al., 2008).
The increasing urbanized future and the demand for cities to “sustainably meet the demands of present and future populations” has become an urgent topic in academic research, city planning and policy, and entrepreneurial spheres. Identifying innovative urban strategies for coping with the challenges posed on cities by population pressure and climate change effects serves as a key to global sustainable development (Camhis, 2006). Structurally integrating ecosystem services into urban landscape design, planning, and management is critical to improving urban landscape resilience and sustainability, and to improving human well-being (Clark & Nicholas, 2013). This will require interdisciplinary research, focusing on solution driven and region-specific case-studies, in order to try and understand both the complexity of problems associated with sustainability, as well as providing insights and opportunities for solution implementation. Efforts to address complex issues such as e.g. food security, or poverty are now often dealt with in a fragmented manner by looking at the issues in isolation, which undermines the formulation of dynamic solutions (Pothukuchi & Kaufman, 1999).
One of the consequences of rapid urbanization is the enormous demands it places on urban food supply systems. Food security is increasingly at risk because of climate change, transport failures, energy supply disruptions, geopolitical insecurity, and many other greatly unpredictable supply shocks (Schmidhuber & Tubiello, 2007; FAO et al., 2017). Increasingly, solutions involve the exploitation of urban agriculture (Crush, Frayne & McLachlan, 2011; FAO, 2012), which could increase social capital, (community) food security and microenterprise opportunities.
Hydroponic vertical farming is a highly technological and advanced form of urban agriculture, and could provide an interesting approach for policy makers to increase food security in the urban environment by means of intensification of production, strategic urban planning and more efficient use of resource inputs (Despommier, 2011). The possibilities of hydroponic vertical farming look rather promising (May & Rogerson, 1995) as it produces food while making optimal use of resources, it generates an income for the workforce and it recycles waste. Worldwide demand for innovative and integrative technologies like these is spiking in light of the urbanization and climate change trends, creating opportunities for entrepreneurs to step in and invest in vertical farming projects. However, the vertical farming technology is new, expensive and requires some basic infrastructure to be able to operate, such as the availability of water, energy, nutrients, a cooperative political
environment and a market for the produce output. Infrastructure which could be especially problematic in developing countries1.
The research aim of this paper is to construct a checklist of these very basic necessities that the establishment of a hydroponic vertical farm requires; so entrepreneurs can easily assess whether cities offer an enabling environment for hydroponic vertical farming projects to be developed and implemented. This framework will then be applied and tested in a case study on the South African city Cape Town. The research question of the paper is: “What are the basic requirements a city in a developing country needs to operate hydroponic vertical farm at full efficiency and does Cape Town, South Africa meet these requirements?” In order to be as inclusive as possible, the scheme will seek to include all the factors of Cape Town’s environment that could affect the feasibility of implementing a vertical farm. For this an interdisciplinary approach is needed as the determining factors range from biological and ecological factors, to cultural, economic, and political factors. We will first introduce the concept of vertical farming and the associated advantages, and touch upon the existing knowledge gap. Secondly, we will integrate the multidisciplinary knowledge of the necessities of a vertical farm into a checklist framework. In the third section this framework will be applied to a case study on Cape Town. The implications of the results revealed in the case study for theory and future research will be addressed in the concluding section of the paper.
Theoretical Framework
The Vertical Farm
Vertical farming is the practice of food production in vertically stacked layers, vertically inclined surfaces and/or it is integrated in other (existing) vertical building structures. Vertical farming exists in many different forms and can range from extremely primitive forms (e.g. sack farming) to highly technologically advanced systems. For this paper we will examine the most advanced and efficient vertical farming system currently available; a closed system with environmental control, using hydroponic technology.
The verticality of the farm makes it especially suitable for usage in areas where land space is scarce/and or expensive, such as urban environments. Being able to produce food at the spot of consumption drastically reduces transportation costs and improves the quality and freshness of the produce.
Hydroponics is a relatively new technology that is deployed in many of the modern vertical farm designs today. It consists of the two parts “hydro” meaning water and “ponos” meaning labour in Greek: “it works with water”. In hydroponic agriculture system crops are cultivated in nutrient-rich water solutions, instead of in a soil (Jones, 2016). In a closed system the nutrient solution is recycled. At the end of the system, the used water is pumped back into the reservoir again, so that the plants can absorb the unused nutrients. The solution is monitored and kept at the desired level of nutrients (see figure 1 and figure 2) (Emerson, 2014), creating the perfect conditions for plants to grow.. A modern vertical farm also uses controlled-environment agriculture (CEA) technology. These
1 A developing country is a nation or sovereign state with a less developed industrial base and/or low GDP and
a low Human Development Index (HDI) relative to other countries (Sullivan, 2003). According to the IMF World Economic Outlook (2015) South Africa can be considered a developing country.
technologies enable farmers to control all environmental factors (light, temperature, humidity, gases, etc.) within the closed system of the vertical farm (Kozai et al., 2015). Therefore all conditions for the crops to grow can be optimized to increase efficiency, and production can be realized all year round. Additionally, because the system is closed, it is immune to any detrimental external influences, such as pests, insects and extreme weather events; limiting the need for pesticides and insecticides, as well as decreasing the risk of complete harvest failure.
Figure 1. A closed hydroponic system with 12 crop positions (Emerson, 2014).
Hydroponic vertical farms exist in many different sizes, with different resource inputs and yielding efficiencies. One working model of a vertical farm was chosen to serve as base for the theoretical framework and checklist. The choice for this particular model was done based on the availability of data and schematics. The chosen model fits with the average characteristics of vertical farms described in most literature.
Figure 2. Zipfarm. top: working of hydroponic system, middle: system outlay, bottom: set up of hydroponic vertical farm.
This paper will use a hydroponic vertical farm from the company Bright Agrotech called the Zipfarm. The farm cultivates 46.5m2 and the following specifications are determined for cultivating lettuce. The growth cycle of lettuce is 3,6 weeks, so 14.44 growth cycles can be produced per year. One cycle requires 1,135.6 liter of nutrient-containing water, adding up to 16,403 liters per year. Furthermore, the farm contains 48 LED light units, each requiring 355 watt. The average lighting duration is 18 hours a day, adding up to a total daily consumption of 1,104,192 kJ and and a yearly consumption of 403,030,080 kJ. These inputs results in a yield of about 480 kg of lettuce for each growth cycle. This is 6,933.33 kg of lettuce each year. A small calculation gives that this hydroponic system will use 58,129.4 kJ/kg/y energy, 2.4 L/kg/y of water and 0.0067 m2/kg/y crops of lettuce.
Tabel 1: Resource use and output of the Zipfarm.
Research Justification
Hydroponic vertical farm is a relatively new and emerging field of land and agricultural sciences and most projects are still found in the development stage. Here and there pilot projects have been implemented and in even fewer cases vertical farms are in a fully matured operating mode (Kozai, Niu & Takagaki, 2015). Although the techniques integrated in vertical farms keep on developing, they are not necessarily new. Greenhouses have made use of similar closed system and controlled environment techniques for a long time. The new dimension that a vertical farm adds, we would argue, is the ideological dimension of providing fresh produce right in the centre of rapidly urbanizing cities, whilst increasing the produce efficiency per square meter and optimizing resource use.
This new dimension implies that high-tech, high-yielding production centres will no longer be placed in the most strategic areas with regards to (natural) resource availability. Instead the ideology of the vertical farm dictates that the farm shall be placed in the urban environment. Paradoxically, the same trends that have given rise to the innovation of vertical farms, are the same ones that could limit the operationalization of this very farm. Namely, rapidly urbanizing cities, placing huge demands on the need for natural resources such as water and energy.
As mentioned before, there is limited knowledge on project implementation available and thus far most projects are or will be implemented in developed countries. These countries offer stable and enabling environments for big investors. The contrary can be true for developing countries2 that still often experience energy blackouts, water shortages and unstable or weak governance. In light of the positive outcomes vertical farms could create for rapidly urbanizing developing cities, we will aim to construct a framework for entrepreneurs to assess the availability of the fundamental requirements for operating a ZipFarm in cities in developing countries.
Theory Development: The ZipFarm Checklist
This framework is intended to provide the first basic checkpoints for entrepreneurs to assess the available infrastructure in cities in developing countries which are necessary for operating a hydroponic vertical farm. A checklist can be valuable for the quick and orderly assessment of the criteria that should be considered when making a decision and aids the assessor not to forget criteria that otherwise could be taken for granted (Stufflebeam, 2000). In our framework development process we have followed a method for creating a checklist proposed by the Checklist Evaluation Process (CEP) (Stufflebeam, 2000). It asks for project specific details to be integrated in the checklist.
2 A developing country is a nation or sovereign state with a less developed industrial base and/or low GDP and
a low Human Development Index (HDI) relative to other countries (Sullivan, 2003). According to the IMF World Economic Outlook (2015) South Africa can be considered a developing country.
For this we will use our chosen hydroponic vertical model, the ZipFarm. The CEP provides a “checklist” for creating a well-considered checklist. This list can be found in appendix 1. We only executed the steps relevant to our research, as can be seen below:
1. Focus of Checklist task
Our checklist will focus on cities in developing countries, and intends to provide a clear overview of the criteria these cities need to have in order to facilitate the ZipFarm. For this criteria development process we have extensively studied literature available on vertical farms. Furthermore, we contacted the company Bright Agrotech to acquire the specific information and requirements for our choice of the ZipFarm model.
2. Creation candidate list of checkpoints
After inquiring about the necessities for the running of a vertical farm, we found that water, energy and nutrients must be available at all times for the farm to operate at full efficiency, there needs to be a demand for the produced crops cultivated in the farm, and lastly, the business has to be legal by law in the country/city of implementation. This leaves us with the following categories for the checkpoints:
- Water availability - Energy availability
- Nutrient availability & crop correspondence - Political environment
These checkpoints will be assessed by the following subdivisions:
Water availability
The following indicators will be used to determine if enough water is physically and economically available on annual basis for the ZipFarm to operate at full efficiency:
- Annual water use of ZipFarm
- Annual water availability in Cape Town - Annual water use cost of ZipFarm Energy availability
The following indicators will be used to determine if enough energy is physically and economically available on annual basis for the ZipFarm to operate at full efficiency:
- Annual energy use of ZipFarm
- Annual energy availability in Cape Town - Annual energy use cost of ZipFarm Crops and nutrients
The following indicators will be used to determine if produce output is conform local diet and whether the necessary nutrients are physically and economically available on annual basis for the ZipFarm to operate at full efficiency:
- Nutrient use of most efficient crop grown in ZipFarm - Dietary preferences of local consumer
Political environment
The following indicators will be used to determine if the political environment is suited for implementing the ZipFarm:
- Policy on agriculture
- Comparison formal policy to de facto practice - Political stability
3. Determination of order and importance of categories
Our Checklist focuses on the fundamental requirements that a ZipFarm needs in order to operate at full efficiency. This means that each requirement is attributed the same level of importance.
5. Explanation of how to apply checklist.
The checklist forms as a guideline to assess the suitability of a city to accommodate a vertical farm. In order to come to a decision, extensive research on every checklist point is needed. This research could be done in various ways such as field research, contact with actors, literature research, newspaper research, etc. It is highly recommended to look at different sources during your research in order to create an objective view of every pro and evey con you come across at checklist points in order to come to an overall conclusion of a positive or negative advise. If extensive research into a checklist point leads to a negative advice, it would mean that the location is either not suitable for a hydroponic vertical farm or a new, innovative solution should be developed to overcome the problem that led to the negative advize.
6. Explanation of when checklist criteria has been met/how to read results.
A city has successfully passed the Checklist when all four of the checkpoint criteria have been met. All criteria are fundamental for successfully running the ZipFarm. Therefore if only one of the criteria has not been met by a city, it automatically means that the city obtains a negative investment recommendation. Simply because with any one of the requirements missing, running the ZipFarm is nearly impossible.
However, it must be noted that it is very unlikely for cities to completely fail at one or more checkpoints. In light of this our Checklist should be viewed upon more as an explorative first check. After this check it becomes clear what problems an investor/entrepreneur might encounter and which areas require special attention or more in-depth analysis of possibilities for enhancing infrastructure facilities for operating the ZipFarm.
7. Overview of checklist in figure.
Methods & Data
For the creation of our hydroponic vertical farm Checklist, we used a method called the Checklist Evaluation Process (Stufflebeam, 2000). This process provides an accessible and orderly way of determining and assessing the checkpoints that need to be integrated in the final Checklist. We followed the steps using information found through extensive literature research.
For our case study we then applied our own vertical farm Checklist onto the city of Cape Town in order to assess its ability to accomodate a ZipFarm. To answer the question whether energy, water and nutrients are physically and economically available for the ZipFarm to operate at full efficiency, we will first determine the availability of these resources in Cape Town now and in the years to come. Then the annual required quantities for the ZipFarm will be determined, and finally the costs of these quantities will be calculated. For these calculations and for analysis of the local dietary preferences and the suitability of the political environment extensive literature research has been conducted, making use of scientific articles, reports and legislation from the municipality of Cape Town and of South Africa, web pages of vertical farming companies, data provided by the FAO, AFSUN, HCP, FFP3, web pages of vertical farm companies and news articles.
3 Food and Agriculture Organization (FAO), African Food Security Network (AFSUN), Hungry Cities Partnership (HCP), Fund
Results
Water
2015 and 2016 had the most drought periods recorded since 1904 for South-Africa and 2017 is even more dry (Figure 3), due to this, Sub-Saharan Africa will deal with major water shortages (Green Cape, 2017b). According to the City of Cape Town and the national Department of Water and Sanitation of Cape Town (2017), the water storage of the six major local dams of Cape Town has declined significantly to only 36.1% of the total availability. Nyong & Niang-diop (2006) determined, using climate models, that in 2050, the average temperature will rise by 0.5°C–2.0°C and the annual rainfall will drop with 10%. Due to this decline of rainfall, the surface water access of Africa will decrease by 25%. In South-Africa, this decrease can go up to 50%, so Cape Town can lose even more than half their perennial supply (De Wit & Stankiewicz, 2006). Due to this warm and dry trend in the local weather, two third of the water behind these dams is used for irrigation of conventional agriculture (Green Cape, 2017b)
Figure 3: Accumulated daily rainfall in Cape Town From 1977 till 2017 source: (CSAG, 2017)
A change in water usage of Cape Town is needed, to deal with these water shortages. There are some opportunities like industrial water reuse, recycling and resource recovery, water and energy, smart water use, water-sensitive design for rain, greywater and stormwater harvesting, groundwater and managed aquifer recharge, desalination and reducing municipal non-revenue water, which can increase the water availability in the future (Green Cape, 2017b), but most of these solutions are expensive and require high-end technology.
The ZipFarm, uses 2,4 L water per kg lettuce produced. Hoekstra (2008) and Roux et al. (2016) both state that, a kilogram of lettuce has global average water footprint of 130 litres during conventional farming. So the Zipfarm uses about 50 times less water than conventional farming (Barbosa, et al., 2015). Agriculture is nowadays the sector, which uses the most water with 69%, because of irrigation (Green Cape, 2017b).
When water becomes more scarcer, it becomes more expensive. The industrial water tariff in 2017 in Cape Town is 25.35R (€ 1.55) per kilolitre (Green Cape, 2017b). The annual production of the Agrotech farm is 6.933,33 kg, the farm uses 16.640 litres, so the total price is € 25,87 for water consumption per year.
Energy
The three main aspects of a hydroponic vertical farm that require sufficient energy are light, heating and cooling, and transportation of water and nutrients.
Energy usage Energy for light
The vertical farm by Agrotech uses additional artificial lighting, since there may not be enough natural sunlight reaching the crops to ensure maximum crop production and maximum yield. The ZipFarm is designed to be able to fit into any space, but it is recommended to use a closed space in which (almost) no light is coming in to be able to regulate lighting as much as possible, which is more energy efficient and causes a better optimization of the controlled environment (Kozai, Niu & Takagaki, 2015). Lighting accounts for roughly 80% of the total electric use in a vertical farm (see table 2). The ZipFarms developed by Agrotech are 500 square feet and are calculated to use a total of 306.72 kilowatt-hours daily (Arnold, 2017), which is roughly 111,952.8 kilowatt-hours per year. The ZipFarm uses 48 lighting units which each need 355 watts to operate and provide 18 hours of daily lighting.
It is suggested to use light with high photosynthetically active radiation (PAR) values, which are used to achieve higher crop yields and shorter crop cycles (Campillo, Fortes & del Henar Prieto, 2012). The best lights to use are LED lights which have high PAR values. These lights, according to the company Ecobain, cause shorter production cycles, uniform intra-layer growing, less tip burn and more appealing coloration (Philips & Ecobain, 2016). Nevertheless, these lights will increase energy consumption and are a higher investment (Kozai, Niu & Takagaki, 2015).
Energy for heating ventilating and air conditioning
According to Brechner & Both (1996) computer technology is an integral part in the production of hydroponic lettuce as a computer controlled system is used to control different abiotic environmental factors. The parameters that can be measured and regulated using computer technology are temperature of the air and nutrient solution, relative humidity and carbon dioxide concentration of air, light intensity of artificial lighting, pH, Dissolved Oxygen (DO) levels and Electrical Conductivity (EC) of the nutrient solution.
The intensity of regulation is dependent upon outside temperature, humidity and other climate factors, which all have a different impact on the need for regulation.
In Cape Town, the minimum average temperature is a little below 14 degrees Celsius (during the winter) and the average maximum temperature is around 27 degrees Celsius (during the summer). The optimal temperature for lettuce to grow is 21.6 degrees Celsius which is a little above the
average yearly temperature of 20.5 degrees Celsius. Therefore it can be assumed, that the outside temperature is beneficial for the production of lettuce and there is only need for small temperature adjustments. (www.worldweatheronline.com, 2017) Relative humidity is often set at a minimum of 50% and no higher than 70% (Brechner & Both, 1998), Cape Town does have a high humidity rate with a maximum of 75% and a minimum of 60% and therefore daily regulation of humidity is needed to avoid a humidity higher than 70%.
If we look at table 2 we can see that cooling, which is controlled by Heating Ventilation and Air Conditioning systems (HVAC systems) account for 16% of the total energy consumption of a vertical farm. Therefore it can be assumed that the energy consumption is 22,390.56 kilowatt-hours per year (111,952.8/(80*16)).
Energy for transportation of water and nutrients
Transportation of water and nutrients happens via pumps and is regulated via a controlled system, this takes up the smallest amount of energy.
The energy demand summary of a hydroponic vertical farm (not developed by Agrotech) in Suwon, South Korea shows that around 90% of the energy consumption is due to light, 6,3% is due to dehumidifiers, 2,2% is due to ventilation systems and 0,3% is due to geothermal heat pumps (Alter, 2011).
Table 2. Percentage of annual electricity consumption by components (Ohyama & Kozai, 2004)
Energy availability
The largest energy provider in Cape Town is the company Eskom, which is the 7th largest electricity generator in the world and supplies 95% of electricity in South Africa. The electricity structure in Cape Town is aged and inefficient, and reserves are not expected to meet demand in coming years. Eskom owns three power plants, namely Koeberg, Acacia and Ankerlig. Koeberg, which is a nuclear power plant, functions as the base load. Acacia and Ankerlig are mostly used to meet peak demand and are diesel operated. However, when Koeberg is undergoing maintenance, the city relies on the South African national grid. This makes the resilience of Cape Town’s electricity supply low, which has resulted in subjection to load shedding.
It is advised to “switch off and unplug all electronics and appliances when the power is due to go off as it may come back with a spike in the voltage, which can damage electronic devices”. Load shedding power outages generally last for about 2 hours and 30 minutes. The loading schedules for multiple area codes can be found on the website of the city of Cape Town (The city of Cape Town, 2015).
A power cut for about 10 hours does not significantly affect plant growth. If there would be a blackout that leads to a light period of only 10 hours, the following light period can be extended to 20 hours or so to minimize damage. (Kozai et al., 2015)
Therefore, the load sheddings in Cape Town are not a threat to crop cycles or crop development, they do however form a threat to electronic devices which could form a problem because of the highly electronically equipped environment of the vertical farm. Damage of electronic equipment could lead to deregulations in the controlled system.
Energy costs
Figure 4. historic and expected energy costs of Eskom electricity (Green Cape, 2016)
Energy costs of the electricity generated by Eskom is expected to grow in the future. In 2018 the energy price is expected to be around 105 Rand per kilowatt hour, which is € 6,45 ,- per kilowatt hour. The vertical farm (ZipFarm) by Bright Agrotech uses an estimate of 139,941 kilowatt hours a year, which results in a cost of €903,305,- annually, €75,275,- monthly.
Crops and nutrients
Lettuce is known to be the easiest crop to cultivate, a crop that produces the most amount of food in hydroponic vertical farming and a crop that does not need much nutrients and water in comparison with other crops (Resh, 2012; Jensen, 1997; Barbosa et al., 2015). Therefore, and because of the use of lettuce in the Zipfarm examined in this research, nutrient needs will be examined for a yield of 6933.33 kg lettuce/year, which is the yield of the Zipfarm in described in the theoretical framework. The most efficient amount of Nitrate to add to lettuce is 22.4 kg/ha (Hamilton & Bernier, 1975). In Minnesota 6290 kg/ha of lettuce can be derived (Cardwell, 1982). This makes 0.004 kg of N per kg of lettuce. As the yield in the ZipFarm is 6933.33 kg/lettuce a year, 27.7 kg N/year is needed for the ZipFarm. The most efficient amount of Phosphor to add to lettuce is 34.4 kg/ha (Hamilton & Bernier, 1975). When having 6290 kg/ha of lettuce, the amount of P per kilogram of lettuce is 0.005 kg. Having 6933.33 kg lettuce a year (Bright Agrotech, 2017), the amount of P per year is then 37.9 kg. The most efficient amount of Potassium to add to lettuce is 133 kg/ha (Hamilton & Bernier, 1975). When having 6290 kg/ha of lettuce, the amount of K per kilogram of lettuce is 0.02 kg. Having 6933.33 kg lettuce a year (Bright Agrotech, 2017), the amount of K per year is then 146.6 kg.
However, when researching the food culture of Cape Town, lettuce is not present in any scientific article on Cape Town. The assumption that then could be made is the lack of lettuce in the dietary preferences of the people in Cape Town (Labadarios et al., 2005), which means it is not profitable to
grow lettuce if the crop is not eaten by the population of Cape Town (Labadarios et a., 2005). This is the main reason to advise against growing lettuce in a Cape Town ZipFarm.
Commonly consumed food products in Cape Town are maize, sugar, tea, milk and brown bread (Labadarios et al., 2005). Of these products, maize and soybeans are mainly used in Cape Town’s dishes and are thus a big part of the food culture of Cape Town (Labadarios et al., 2005).
Maize is also eaten in various other countries worldwide and is also a staple in other African countries like Kenya (Odendo et al., 2001; Jones & Thornton, 2003; Oerke, 2006; Oerke et al., 2012). This is the main reason to choose for researching the cultivation of maize in a hydroponic vertical farm.
For maize to have an optimal yield, it has to be cultivated by adding different amounts of nutrients and water than lettuce. According to Eck (1984) too much nutrients are often added to crops instead of too few. Whereas most farmers add 210 kg N/ha to their maize crops, 140 kg N/ha is sufficient for maximum yields (Eck, 1984). But optimal yields for maize lie around the application of 180 kg N/ha (Ren et al., 2015). The yield that can be derived from this amount of Nitrate is on average 6290 kg/ha in Minnesota (Cardwell, 1982). So for 1 kilogram of maize approximately 0,03 kilograms of N is needed. The ZipFarm produces approximately 6933,33 kg/year on an area of 46,5 square metres (Bright Agrotech, 2017). This means for this ZipFarm approximately 198 kg N/year is needed. In addition to Nitrate, also an amount of Phosphate and Potassium is needed for the growth of maize. The optimal amount of Phosphate that should be added to maize crops is 90 kg P/ha (Ren et al., 2015). With the same calculation as Nitrate this means for 1 kg of maize 0,01 kg of P is needed. For the ZipFarm this means approximately 99 kg P/year is needed. The amount of Potassium that should be added to maize crops is 120 kg K/ha (Ren et al., 2015). Using the same calculations as the nutrients above 0,02 kg of K is needed for 1 kg of maize. For the ZipFarm this means approximately
132 kg K/year is needed.
This amount of nutrients should be available in Cape Town, as Eck (1984) stated that often too much nutrients are added to crops than too few and Van Den Braak (2017) stated that nutrients are available almost everywhere, so this should not be a problem for Cape Town. However, small holder farmers in Cape Town are having a hard time adding fertilizers to their crops. Due to the high prices of fertilizers in Sub-Saharan African countries in comparison with other developing countries, African farmers do not fertilize their crops enough (Heisey & Mwangi, 1996). In combination with the removal of subsidies for fertilizers in South-Africa a few decades ago, this was nevertheless a problem in Africa and therefore in Cape Town as well (Heisey & Mwangi, 1996). But to create sustainable finances and at the same time reach out for the poorest, multifinancial institutions (MFI’s) are set up in multiple countries in Sub-Saharan Africa (Churchill). These institutions get subsidies from the government to help the poor people improve their lifestyles. Give subsidies on fertilizers for smallholder farmers are part of the things MFI’s do (Churchill), but for this study it is the most important task. Access to fertilizers and the availability of fertilizers is thus not a problem in Cape Town.
The only problem that still exists is the amount of space. Maize is a tall crop and is therefore difficult to grow in hydroponic vertical farms; even impossible in the ZipFarm used in this research. There is no soil to keep the crop standing. For short crops this would be no problem, but for crops like maize
this is a problem. Apart from the fact that maize plants cannot stand upright, maize plants need space which means the space in a vertical farm will not be used efficiently. Fewer crops fit in the farm than the amount of smaller crops that will fit in.
Policy
According to the Fragile State Index (FSI) 2017, South Africa can be classified as a relatively fragile state, scoring 72,3 out of 120 with a score of 1 being the most fragile and 120 the least and has been doing worse over the past decade, findings itself now in a warning stage for fragility and unrest (Fund For Peace (FFP), 2017ab). Having a fragile state relates to two issues that might hinder implementation of the ZipFarm, namely: formal rule enforcement and political stability, each of which will be discussed below.
Policy review
Rogerson (1993) notes that local authorities in the past have not met urban agriculture with such great enthusiasm, or have even greatly resisted any efforts by people to practice urban farming. Especially property and land rights had been structurally violated. However, in more recent years we can see the role of urban agriculture, and the value attached to it, increasing (FAO, 2012; Frayne, McCordic & Shilomboleni, 2014; May & Rogerson, 1995; Rogerson 1993) and more projects are emerging (Battersby, Marshak & Mngqibisa, 2016; "Vertical agriculture", 2011).
This development is underscored by the approval of the The City Of Cape Town Urban Agriculture Policy 2007 (CoCUAP) by the municipality in 2006 (City of Cape Town, 2007), elucidating the positive attitude of the Cape Town’s authorities. However, as is the case in many developing countries, the formal rules of politics are often irrelevant to de facto political outcomes (Eaton, 2006; Soifer, 2012). Where the government is weak and capacity, reach and/or willingness to implement is low, changes in formal rule of law may have little or no effect on practice and can be just as easily ignored or diluted by local power holders (Soifer, 2012). Drawing upon the FSI 2017 it becomes apparent that South Africa’s state capacity has dramatically decreased in the past year, and has been low throughout the years, as can be seen in figure 5 below displaying “State legitimacy” (Fund For Peace, 2017a). It is therefore necessary to elucidate the intersection between policy and practice (Minné, 2012; Soifer, 2012).
Figure 5. State legitimacy, South Africa 2006-2017. Source: FFP, 2017b The CoCUAP aims to “develop an integrated and holistic
approach for the effective and meaningful development of urban agriculture in Cape Town … to create more real and sustainable opportunities for local area economic development”. (City of Cape Town, 2007, p.2). The policy stresses sustainability as well as economic development within the field of UA, two issues that fit perfectly with the ideology of the vertical farm. In the policy urban agriculture is understood as: “The production, processing, marketing and distribution of crops and animals and products from these in an urban environment using resources available in that urban area for the benefit
largely of residents from that area.” (City of Cape Town, 2007, p. 3). Deriving from this concept definition we can conclude that vertical farming can be understood as a form of urban agriculture, implying that vertical farming would not only be legal but also very much supported.
Ultimately, this policy will give “formal recognition to urban agriculture in the City Of Cape Town” (RUAF Foundation, 2007, p. 2). This is probably the most important asset of the policy, since lack of property and land rights are often recognized as one of the biggest burdens on investments in developing countries, for both local and international investors. Uncertainty and fears of unconstitutional land or property expropriation make it highly unattractive to invest De Soto, 1989; Green Cape, 2017a).
Formally, the ZipFarm should not encounter any challenges, but as mentioned formal rule often differs with de facto practice, and local power holders opposing UA practices could hinder development. Minné (2013) has also identified this nonconformity of formal and de facto rule in the CoCTUAP. This nonconformity however, mostly dealt with lack of communication between municipalities and human resourcing constraints in delivering on policy interventions to the lack of clear instructions for the policy implementation. None of the implications observed by Minné (2013) identified any issues that corrupted implemented projects in relation to land or property rights, they were related only to a lack of incentive to encourage urban farming.
Zooming out of the CoCTUAP and looking at a more extensive overview of the existing policy on land use and agriculture (related) practices, which can be found in table 3. The policies all direct a certain focus to more sustainable use of resources and land and so it can only be concluded that the ZipFarm fits perfectly in the overall ideology of land and agricultural policy design in South Africa in general, but also of Cape Town in specific.
Table 3. Selected acts and policies relevant to the agricultural sector (Green Cape, 2017a).
Policy / Act Objectives
The Conservation of Agricultural Resources Act 43 of 1983
■ Controlling use of natural agricultural resources ■ Conservation of soil
■ Conservation of water sources ■ Combating weeds and invader plants The National Development Plan 2030 (NDP 2012) ■ Elimination of poverty
■ Reduction of inequality
■ Highlighting the importance of initiatives that link agriculture to the green economy
The Medium Strategic Framework (MTSF 2014-2019) ■ Outcome 4 – Decent Employment through Inclusive Growth
■ Outcome 7 – Comprehensive Rural Development and Food Security
■ Outcome 10 – Environmental Assets and Natural Resources Protected and Continually Enhanced The Spatial Planning and Land Use Management Act
(SPLUMA 2013)
■ Provides for a uniform, effective and
comprehensive system of spatial planning and land use management for the Republic
land
■ Redresses the imbalances of the past and ensures equity in the application of spatial development planning
National Environmental Management Biodiversity Act (NEMBA 2004)
■ Provides for the management and conservation of the biodiversity within the framework of NEMA ■ National protection of species and ecosystems that warrant national protection
■ Sustainable use of indigenous biological resources ■ Fair and equitable sharing of benefits arising from bioprospecting involving indigenous biological resources
■ Establishment and functions of a South African National Biodiversity Institute
Political Stability
Political instability, does pose certain challenges and might make South Africa an unsuited country for a high cost investment like the Zipfarm. Although the FSI (see figure 6.) does not predict unrest or turmoil yet, it does warn for worrying increases in the conditions that can likely give rise to instability. The FFP (2017b) shows that South Africa has made a dramatic fall in terms of economic development (see figure 7.), public services have gotten worse as have the security apparatus, state legitimacy and more. These are issues that could cause problems for capital flows, rights protection and ultimately even lead to (armed) conflict and this is always a risk when it comes to investment in developing countries. South Africa however, compared to its continental counterparts is still doing relatively well (FFP, 2017b). And the FSI focuses on countries as a whole only, whereas especially in bigger cities like Cape Town, state decline is often least noticed. It is the bigger cities (in the most part of the city) where state capacity and reach is strongest, as most resources are concentrated in the urban hotspots (Eaton, 2006; O’Donnell, 1998; Soifer, 2012). This puts the real risk of political instability and its consequences for (foreign) investment in perspective for a city like Cape Town.
Figure 6. FSI, South Africa. Source: FFP, 2017b Figure 7. Economic Decline, South Africa.
Conclusion
This paper developed a framework for assessing the requirements necessary for operating a hydroponic vertical farm at full efficiency in a city in a developing country. It used the CDC for developing a Checklist with these requirements, making it easy for entrepreneurs to assess cities. In order to provide a specialized checklist we focused on a hydroponic vertical farm, which resembles average farms found in the literature, called the ZipFarm. After extensive literature research we found the following requirements to be essential for our ZipFarm to operate at full efficiency: water, energy and nutrients need to be physically and economically available at all times, the produce needs to be compatible with local dietary preferences and the political environment needs to be suitable. The checklist is then applied onto a city of choice, after which the entrepreneur obtains an easy advice for or against investing in the respective city. The Checklist, however should be viewed upon more as an explorative first check. After this check it becomes clear what problems an entrepreneur might encounter and which areas require special attention or more in-depth analysis of possibilities for enhancing infrastructure facilities for operating the ZipFarm.
As a case study we have applied the Checklist onto the city of Cape town, South Africa. We found the following results:
Firstly, the water availability in Cape Town is scarce and with pressures of climate change increasing, the availability will likely become even less. Therefor Cape Town does not meet the water requirements checkpoint for the Zipfarm.
Secondly, energy availability is unreliable due to the fact that there is only one base load facility, which, when the base load facility is undergoing construction, can cause blackouts. The re-initialization after these blackouts can damage equipment and could therefore damage the control system on which hydroponic vertical farming is reliant.
Thirdly, nutrient availability is not a problem in Cape Town nowadays and in the near future. However, as both lettuce and maize are not yet profitable to be cultivated in the ZipFarm according to literature research, because lettuce is not implemented in the food culture of Cape Town and maize is too tall to grow in the ZipFarm, building a ZipFarm in the city is not the most efficient location.
Lastly, the City of Cape Town Urban Agriculture Policy of 2007 formally recognizes urban agriculture, so operating our ZipFarm would be legal and no negative de facto practices regarding land and/or property rights violation were identified. The FSI does warn for future unrest and state decline, however the FSI looks at countries as whole, whereas the big cities usually enjoy state presence more than rural area. No big challenges are expected and Cape Town passes the political environment checkpoint.
Table 4. Results Cape Town ZipFarm Checklist. Source: ZipFarm, 2017
Cape Town Pass Fail
Water Availability X
Energy Availability X
1. Nutrient Availability 2. & Diet Compatibility
Nutrient Availability & Diet Compatibility Total
X
X X
Suitable Political Environment X
Total Pass/Fail 1 3
Deriving from these results we can conclude that the city of Cape Town does not meet all the criteria of our checklist to run a ZipFarm at full efficiency. Water is scarce, the electricity supply is unreliable and the most efficient produce is not compatible with the local diet. Therefore, investing in a ZipFarm in Cape Town would be advised against.
Discussion
We have concluded that on basis of our Checklist Cape Town would not qualify as a suitable city for implementing a ZipFarm. However as mentioned before, our Checklist should rather be interpreted as a first explorative check, to warn entrepreneurs and encourage them to closely examine rejected checkpoints in order to create a greater understanding of the limitations or opportunities a city has. In the end it is up to the entrepreneur to assess the importance of different (dis)advantages and make a decision on the basis of this evaluation.
Closer examination is useful for most of the checkpoints: Water
Cape Town’s water availability is very little and is still decreasing, so new vertical farms in addition to the conventional farms might not be possible. However, water usage in hydroponic vertical farming techniques is 50 times less than in conventional farming techniques, so a hydroponic vertical farm could be a good replacement and contribute to more sustainable use of water in the future, making more agriculture possible.
Energy saving options
Literature research has shown that energy requirements for lighting in a vertical farm are very high and energy infrastructure in Cape Town is not reliable. Therefore it would be advisable to look at other energy sources beside Eskom. Eskom also provides a great deal of “grey energy” (energy from unsustainable sources) which would not be preferred in light of making the vertical farm as sustainable as possible. Therefore we propose to look at other energy options, such as solar energy, of which the price has rapidly decreased over the last decade and which may even be cheaper than
energy from Eskom (figure 8). To assess whether other (renewable) energy sources should be a good option, further research has to be done on the availability and costs of these energy sources in order to assess if this would be a good substitute for the energy of Eskom.
Figure 8. Average Eskom tariffs versus renewable energy tariffs (GreenCape, 2014) Crop diversity
As both lettuce and maize are not suitable for cultivation in the ZipFarm in Cape Town, further research needs to be done to crop cultivation. Labadarios et al. (2005) states that also soybeans are a staple crop that is eaten by the population of Cape Town. This could be a suitable crop to cultivate in the ZipFarm as the crop plant is smaller than maize and is present in the food culture as stated above. Besides, literature research is lacking information on lettuce in dietary preferences of the people in Cape Town. However, further qualitative research in the city could be done to support this. Implications concept “developing country”
No real specification of what classifies a country as developing has ever been agreed on. A lot of controversy has surrounded the term and the use has declined, so its use might not be as meaningful in future research. We however have used this concept as provided by the IMF Economic World Outlook in our framework since the focus is mainly on assessing basic infrastructure requirements, which often lacks in precisely those countries that classify as developing in the IMF’s definition of the concept. The use of the framework is therefore focused, but not limited to “developing” countries.
Recommendations
Our checklist was optimized for the ZipFarm model. Therefore the Checklist is not readily applicable for hydroponic vertical farms in general. However, we have explained our process of the Checklist framework development. Entrepreneurs can easily follow the same steps as shown in the paper’s Theory Development part and consult the checklist development tool (Appendix 1.) from Stufflebeam (2000) and add or delete any characteristics that are (ir)relevant for the desired hydroponic vertical farm design or city of choice.
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Appendix 1.
