A SUSTAINABLE ENERGY SUPPLY SYSTEM IN AQUACULTURE  

As fish food channels have been globalized, aquaculture industry has become more energy intensified and expanded to meet the gaps in the global fish supply. Currently, land-based aquaculture systems have continuously gained popularity in the U.S. due to advantages, including higher fish productivity, less climatic impacts, and geographical benefits by locating a fish farm close to markets. Due to incessant use of equipment, however, the land-based systems require considerably larger energy than other forms of or marine-based fish production systems (e.g. pond, cage). As the energy-intensive systems will be expected to further expanded, future aquaculture should find a way to improve aquaculture energy supply systems for sustainable fish production. A key barrier to this achievement is a lack of understanding of environmental and economic performance profiles of conventional and alternative energy sources in aquaculture.

In this study, an energy system assessment tool was developed considering various energy sources: renewables (solar photo-voltaic, solar water heating, and biogas) and conventional energy sources (electricity, natural gas, propane, and diesel). Energy analyses of two different land-based culture systems were performed in order to estimate electricity and heat requirements. These include a Recirculating Aquaculture System (RAS) of red drum production and an aquaponics system for trout production. Currently, various types of solar PV systems (mono-silicon, poly-silicon, and thin-film) and an electricity grid for an electricity system were evaluated through the tool.

For both culture systems, the use of thin-film solar PV system was determined as the most environmentally favorable option among different electricity systems (Figure 1, Left). On the other hand, for economic benefits, mono-crystalline solar PV system was the most economic option, although payback times of the two solar PV systems were not considerably different (Figure 2, Right).