Assessment of potential renewable energy alternatives for a typical greenhouse aquaponics in Himalayan Region of Nepal

Greenhouse aquaponics (GA) can serve as a sustainable food production method, potentially improving food and nutrition security in resource-constrained and hostile climatic zones such as Nepal's Himalayan region. Energy concerns, however, are one of the major barriers to GA adoption in this region. There is a lack of comprehensive energy demand analysis for GA operations. Therefore, in this study, an energy model for GA based on a quasi-static energy balancing technique was developed to estimate energy demand for the Himalayan region. The study was conducted in 19 districts with varied GA dimensions, and a linear-model was fitted to predict yearly energy consumption. Thereafter, relations to estimate the capacity of PV systems for supplying the required energy were devised. Eventually, this study proposes potential energy management strategies to reduce dependency on a single energy source, reduce energy loss, and enhance resilience to energy concerns. Findings suggest, heating the GA is a major energy concern, accounting up to 85% of the overall energy requirement. Thermal evaluation reveals that conduction and convection losses are the most significant, contributing up to 29.5% of total energy consumption. Moreover, this study testifies the effectiveness of thermal energy storage devices in achieving significant energy savings. The proposed energy management strategies can serve as a decision-making tool for optimizing the design and operation of GA. Furthermore, this research serves as a blueprint for addressing aquaponics related energy challenges worldwide, especially in areas with similar climatic conditions, such as the Hindu Kush Himalaya (HKH) region.