WWW.WAS.ORG • WORLD AQUACULTURE • MARCH 2023 33 2020). However, in extreme cold, the cost savings from reduced heating requirements can offset the electrical cost of lighting and even outperform greenhouse production profitability under optimal conditions (Avgoustaki and Xydis 2020, Eaves and Eaves 2018). Grow lights account for approximately 22 percent of capital costs in indoor agriculture systems and as much as 25 percent of the reoccurring electrical budget (Agrilyst 2017, Goodman et al. 2005). Although LED lights are often thought to be more economical due to their perceived operational efficiency, the cost per mole of photons is 2.3 times higher for LEDs than for double-ended highpressure sodium (HPS) lights. With almost identical five-year efficiency values, HPS is a better economic investment than LED grow lights (Nelson and Bugbee 2014). The primary difference in economic viability was the high fixture cost of LEDs, which should decrease as technology progresses. System scale. Aquaponic technology can be applied at many scales, from industrial down to benchtop systems, implying a range of resource use efficiency and profitability. As farm scale increases, farmers should be able to produce more product, but this comes with additional fixed and variable costs. The benefit to larger operations is that building and production system infrastructure tends to become cheaper on a unit area or water volume basis. Additionally, heating, lighting, and labor costs can be spread out across more products for sale, making the cost per unit production lower. Along with system scale, retail produce price is critical in determining profitability. Xie and Rosentrater (2015) demonstrated a greater profit potential for larger systems (>75 m2 growing area) and higher sales prices (>$60/kg for basil). Although the minimum system scale required to make a profit is heavily dependent on local conditions, species produced and market prices, König et al. (2016) suggest a minimum scale of 1,000 m2. The median facility size class for commercial producers in our survey was 500-3000 ft2 (46-279 m2). Love et al. (2014) reported a median facility footprint of 15 m2 (162 ft2), indicating an increase in facility scale over time. As a frame of reference, for the minimum recommended area 1000 m2 to be profitable, 3.5 standard 30 ft × 100 ft greenhouses would be required. Only 17 commercial producers in our survey met this criterion (Pattillo et al. 2022b). Three of four producers expressed an interest in scaling up their operations, indicating considerable growth potential for aquaponics. System design. Interestingly, 73 percent of producers in this study designed their own aquaponic system. Based on the increasing size of aquaponic farms over time, these growers likely learned their do’s and don’ts from making mistakes on a smaller scale. Additionally, the vast majority (84 percent) of producers used coupled systems in which the fish and plant sub-systems are connected. Decoupled systems are gaining popularity because they allow growers to isolate segments of the system, modify temperature and water quality conditions independently and apply pesticides. Solutions Potential aquaponic farmers, particularly in temperate and sub-tropical environments, should enter facility and system planning with eyes wide open. A common mistake is the “if I build it, they will come” mentality. Ensuring that the cost of the facility and system can achieve a ROI is of utmost importance. Although fully automated greenhouses are attractive, many aquaponic businesses have closed due to overdesign and over-investment. The scale of operation is an important factor in assessing economic viability; it is logical to conclude that bigger is better. It is easy to get stretched too thin, especially for owner-operators, and more employees adds another dimension of complexity. Most growers interested in aquaponics do not have the necessary capital or skillset to build and operate a 1000-m2 system. The majority of producers in this study operate pilot-scale (500-3000 ft2; n = 26) to small commercial farms (3000-22,500 ft2; n = 29) (Pattillo et al. 2022b). Aquaponics research should focus on applied studies to reduce production costs for small farmers. Results should not only be representative of smaller, replicated systems. Researchers should (CONTINUED ON PAGE 34)
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