Energy generation and storage using evaporated brines

Energy generation using salinity differences produced by pond evaporation is examined. Solar and wind inputs would drive the evaporation, possibly with enhancement that could make use of a portion of the generated power. Well-known power production technology could be used, for example pressure retarded osmosis, but with seawater as the permeate source. Such salinity systems would provide a medium of energy storage: concentrated brine. They might be of particular interest for service continuity in small markets where standard renewable energy sources are not sufficiently reliable. The concept provides significant engineering challenges. Evaporation ponds would need to be large, but might be marine installations with no land footprint, or might be existing salt evaporation pans. High salinity differences are optimal in this application. With osmotic systems the operating pressures are correspondingly large - adequate membrane technology is yet to be developed. However, novel methods of generating power from salinity gradients are now appearing and familiar methods are now attracting increased attention that is likely to address many of these problems. It can be anticipated that salinity based power can be a promising technology even where salinity gradients do not naturally exist.