Mapping and analyzing energy use and efficiency in a modified hydroponic shipping container

In urban centers today, vertical farming is becoming a popular alternative to conventional agriculture in an effort to increase local food production and improve urban food security by growing crops using hydroponic methods in controlled environment spaces. More specifically, one vertical method involves growing crops inside refurbished shipping containers, or a “farm-in-a-box” concept, which offers a flexible, mobile, and scalable means of year-round food production in a variety of climates. Despite benefits of producing food locally, some of the concerns associated with these vertical farming systems include high energy consumption from climate control and electric lighting systems as well as expensive capital investments. Therefore, this study investigated the viability and effectiveness of shipping container farms as alternative food systems through analysis of system energy requirements and resulting crop yields. A Modified Hydroponic Shipping Container (MHSC) system was designed, and a Nutrient Film Technique (NFT) hydroponics system was tested by growing lettuce plants and monitoring energy use throughout the growth period. Additionally, theoretical energy use was quantified for one year of production at full scale by modeling energy consumption of major system components. Crop production and energy consumption were assessed using a crop production efficiency metric created to evaluate the ratio of system outputs to inputs. A baseline crop production efficiency value was determined, and scenarios for improving system efficiency from the baseline value were then analyzed. As a result, alternative energy scenarios reduced yearly consumption up to 53 percent from baseline consumption. Improvements to the MHSC design through suggested energy use reduction strategies will allow for the creation of a viable and sustainable alternative food system that is capable of providing local, accessible foods year-round for a variety of urban communities