Emergy Assessment of a Portable Solar Still for Water Desalination and Purification

In this work, we present the emergy accounting of an innovative solar still for water desalination/purification. The solar still, named SOLWA, can reach comparatively very high yields in the delivery of water, designed to supply safe fresh water in small isolated communities and in urban contexts where electric network connections or conventional energy sources are not available. SOLWA is portable, and made by "poor" materials and elements, with a total cost of the order of some hundreds USD. It does not require maintenance, and is powered only by solar radiation. Based on the emergy accounting method, we address its sustainability features, and compare the specific emergy of the produced drinking water to that from other conventional systems used for desalina-tion/purification. This work highlights the use of emergy accounting for integrated sustainability assessment, a paramount aspect in the scientific and philosophical legacy of Howard T. Odum, as emergy appears more and more the metric to be used for the definition of sustainable policy-making procedures.