Off-Grid Energy-Air-Water Nexus: Emergy Accounting of a Solar Distiller

New technologies for sustainable advancements in extreme conditions strive to build upon renewable energy sources, yet often hiding problematic upstream requirements, e.g., rare materials, fossil fuels, or power grids. Here, drinking water micro-generation systems for isolated environments are addressed; in particular, an innovative distiller for water desalination/purification is analszed by the Emergy Accounting Analysis (EMA) methodology. The solar still, named SOLWA®, can reaching comparatively very high yields in the production of drinkable water, has been designed for drinkable water supply in small isolated communities as well as in urban situations where electric network connections or conventional energy sources are unavailable, and has already drawn the interest of several nongovernmental organisations, as well as the United Nations, which included SOLWA® in the Innovation for Development and South-South Cooperation programme (www.ideassonline.org). By the EMA method, some sustainability indicators are calculated. A focus is also dedicated to the emergy implications of the purification process as well as to the critical steps in terms of efficiency, i.e., the water-cooling recirculation and the solar collector. Expanding the findings of novel studies about a novel technology, the EMA method allows to further read potentials and limits of such a promising system, including purely ecological and socio-economic inputs upon which both the distiller and its micro-generation process critically depend.