An aquaponic farm with a 76 m
3 tilapia fish tank and a 1142 m
2 DWC lettuce plant growth bed (LPGB) has an initial venture cost of USD 217,078
[94]. Small UVI systems cost USD 285,134, while large UVI systems cost USD 1,030,536 for aquaponic foundations
[95]. The annual net revenues of smaller systems range from USD 4222 to USD 30,761, with IRR and MIRR rates varying from 0 percent to 27 percent
[95]. The UVI system
[48], with a growing area of 214 m
2, could generate USD 110,000 per year by selling only basil, whereas the revenue from selling okra would be only USD 6400. Basil had the highest value per kg (USD 8.80–11.03), and Boston lettuce generated more income per week per m
2 (USD 7.50–9.20) than basil (USD 3.96–4.96) due to higher returns and higher planting density. Not all fruit crops, such as melon, zucchini, and cucumber, had a weekly income per m
2 above USD 1.32. Morgenstern
[96] found that a small-sized aquaponic farm with a 3 m
3 European catfish fish tank and a 59 m
2 DWC LPGB would require an initial investment cost of EUR 151,468. A medium-sized aquaponic farm with a 10 m
3 European catfish fish tank and a 195 m
2 DWC LPGB would have an initial investment cost of EUR 304,570. A commercial-scale aquaponic farm with a 300 m
3 European catfish fish tank and a 5568 m
2 DWC LPGB would have an initial investment cost of EUR 3,705,371. According to Lobillo-Eguíbar
[97], aquaponic infrastructure costs range from EUR 2266.27 to EUR 2252.13 for two small-scale aquaponics systems, generating a family farm income per FWU (family work unit) of EUR 3090.41 and EUR 153.50. A total of 62 kg of tilapia and 352 kg of 22 distinct vegetables and fruits were produced, with a typical net farming value-add of EUR 151.3 and EUR 91.34. The results showed positive accounting benefits and negative economic profit when labor costs were included. The level of commoditization was around 44%, allowing for some specific independence.
5.2. Energy Consumption
Energy consumption in aquaponics systems holds immense significance due to its pivotal role in ensuring system functionality and the well-being of aquatic organisms and plants. As per studies, aquaponic systems in the Midwest and Arkansas reflect annual energy costs ranging from USD 5991.06 to USD 7337.04 within total operating expenses
[98]. Notably, heating constitutes nearly 50% of these costs, albeit subject to significant variability based on farm location
[99][100].
LED lighting stands out in aquaponics for its superior energy efficiency and plant growth promotion compared to other options. Studies highlight LEDs for higher yields, energy savings, and environmental benefits, making them ideal for large-scale aquaponic setups
[101][102][103]. Tailored LED treatments have been effective in enhancing plant growth, improving energy efficiency, and boosting specific plant characteristics
[104]. Studies note that specific LED combinations, like far-red light in red plus blue LEDs, significantly enhance plant growth in lettuce
[105][106]. Optimizing artificial lighting parameters like DLI (daily light integral) and PPFD (photosynthetic photon flux density) play a crucial role in enhancing plant growth and yield
[107][108][109]. Utilizing controlled switching frequencies to shift lighting into pulsed modes significantly improves energy efficiency in aquaponics. These customized “light recipes” yield substantial energy savings compared to continuous lighting while maintaining plant characteristics
[110][111].
The continuous circulation of water is fundamental to aquaponic systems, facilitating the distribution of nutrients essential for plant growth and maintaining optimal conditions for aquatic life. Goddek et al.
[11] underscore energy-intensive issues in aquaponics, particularly within indoor systems that consume significant electrical and heating energy, while also emphasizing challenges in nutrient recycling, pathogen control, and supply chain management. However, the operation of pumps required for this circulation demands a significant amount of energy. The need for a consistent and uninterrupted flow of water throughout various system components contributes substantially to overall energy consumption. Energy-efficient pumps reduce your environmental footprint and save you money on energy costs in the long run. In an aquaponics system, where the water pump runs continuously, the impact of energy efficiency is significant. Efficient pumps consume less electricity while delivering the required flow rate, helping you achieve a more sustainable and cost-effective operation.
Regulating temperatures within an optimal range is crucial for the well-being of both fish and plants in aquaponics. This often involves the use of energy-intensive systems like heaters or air conditioning units, especially in regions with extreme temperature fluctuations. While essential, these systems contribute significantly to the overall energy demands of aquaponic setups.
To address resource conservation, a process engineering approach targets water and energy usage in hydroponics
[112]. Integrating renewable energy boosts system ecological performance. Aquaponics holds potential for efficient and sustainable technology, welcoming integration possibilities like biogas and solar power (reference
[14]).
5.3. Social, Economic, and Environmental Benefits for Food Security
The integration of agriculture in urban areas brings about social, economic, and environmental advantages, contributing to both food security and sustainable development. It also promotes the growth of cities while fostering scientific and cultural knowledge
[113]. From an economic perspective, urban agriculture, including the production of crops, fisheries, and livestock, provides raw food that can be distributed to the city’s residents, maximizing conservation efforts
[113]. While this concept had previously posed environmental challenges, it has now evolved into an environmentally friendly strategy within city centers
[113]. Aquaponics systems, utilizing the principles of the 4Rs (source, rate, time, and place), play a crucial role in enhancing productivity, stability, and profitability, thereby ensuring food security. The four pillars used to assess and measure the status of food security include food availability, accessibility, utilization, and stability
[114]. Evaluating aquaponics’ sustainability reveals that while its infrastructure, electricity usage, and feed pose environmental impacts, this closed-loop system offers a sustainable means of producing fish and plants.
Aquaponics can help achieve food sovereignty goals by providing fresh, healthy, and locally grown food that is secure, satiating, and socially acceptable. The closed-loop system ensures food safety and reduces dependence on imported food, promoting food independence and addressing food insecurity. Aquaponics uses less water than traditional agriculture, reduces the risk of water pollution, and can grow a variety of crops, promoting the safeguarding of natural resources. By increasing access to fresh, healthy, and locally grown food, aquaponics promotes social harmony and reduces the risk of social unrest. It also allows small-scale farmers to have a voice in agricultural policies, promoting democratic oversight and community resilience.