Recirculating Aquaculture Systems (RAS) are efficient farming systems, but energy intensive. Few studies distinguish energy consumption between individual components or identify the factors driving demand. This study aims to characterise baseline energy demand and variability across RAS components. It furthermore quantifies the operational and environmental drivers of electrical energy use by analysing relationships between component-level energy use and production parameters.
Eight identical experimental RAS were run at the Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB) in Berlin, Germany, from May to August 2025 with African catfish (Clarias gariepinus). Smart energy sensors monitored all energy-consuming components during the 13-week feeding trial. Electrical energy use was recorded at system and component levels, as well as biological and environmental conditions. Component-level data were analysed to quantify baseline energy demand and variability among compartments. Regression and correlation analyses identified operational and environmental drivers of energy use. Energy use efficiency was calculated based on the biomass produced and energy used.
The results show that drumfilter energy use increased over time with growing biomass and that energy use for temperature control was highly variable. In total, temperature control dominated energy use at more than 60% of total consumption, followed by the blower (22.27%), trickling filter pump (10.58%), circulation pump (4.68%), and drumfilter (0.87%) (Figure 1). Correlation results indicate that electrical energy use efficiency in RAS strongly depends on external environmental conditions and fish growth performance.
By differentiating energy use among system compartments and identifying the main operational and environmental drivers, this study provides a basis for targeted optimisation of RAS design and operation, supporting more effective energy management strategies in aquatic animal farming.