Feasibility of saltwater gradient ponds as a heat supply for hatchery rearing water

Salt gradient solar collector ponds are economically feasible as a source of heat energy for hatchery rearing water. A pond 3 m deep and covering an area of 5000 m² will supply approximately 2800 GJ of energy over a three-month period — enough for a one-year smolt program in an Atlantic salmon hatchery. The cost to construct such a pond is approximately $173,000, or the equivalent of seven years' fuel bills using conventional heating equipment. Although the technology is new and not entirely understood, existing ponds have proven to be relatively problem free and require only minimum maintenance.