An Optimal Design on Sustainable Energy Systems for Shrimp Farms

Abstract

The energy consumption for aquaculture in Vietnam, especially shrimp farming industry, has continued rising considerably in recent years due to the expand of shrimp production to meet food demand. Most of energy demand at shrimp farms is consumed by aeration system which uses electric motors to drive aerators for improving dissolved oxygen in ponds. In addition, the intensive energy consumption from electric motors for aeration and pumping systems leads to high operation cost and associated greenhouse gas emissions. Although many improvements have been done for the design and operation of aerators and even renewable energy resources have been applied, mechanical aerators still consume high power with low oxygen transfer from air. Therefore, this paper proposes an optimal design for advanced aeration system in which the electrolyzer powered by renewable energy might produce onsite pure oxygen according to the changes of dissolved oxygen level in shrimp ponds. The optimal results obtained from the elitist genetic optimization algorithm with life cycle cost and CO₂ emission as objective functions conducted in off-grid and on-grid modes are compared with mechanical aeration system powered by national grid. The comparison in terms of life cycle cost and CO₂ emission results that the hybrid system supplied by wind and photovoltaic power with national grid as backup represents the best configuration for the investigated shrimp farm because it not only provides better competitiveness for life cycle cost and low gas emission but also procures revenue at the end of the project lifetime.