Comparative LCA of autonomous solar vacuum membrane distillation configurations for seawater desalination

This study presents a comparative cradle to gate life cycle assessment of four solar-powered vacuum membrane distillation (VMD) configurations. VMD including mechanical vapor compression powered with solar thermal energy for heating photovoltaic electricity for pumping exhibits the lowest impacts across several categories. This superior environmental performance is closely linked to its energy efficiency, as it achieves the lowest specific energy consumption (154.6 kWh/m 3 ) while producing the highest water output. Furthermore, the results indicate that solar energy components, including photovoltaic panels and solar thermal collectors, are the primary contributors to the environmental footprint, representing 75–99 % of impacts across all categories. Following the finding an analysis was conducted to assess the effect of collectors type. Three types of photovoltaic panels monocrystalline silicon (sc-Si), multicrystalline silicon (mc-Si), and cadmium telluride (CdTe) and two solar thermal technologies, flat plate collectors (FPC) and evacuated tube collectors (ETC) were considered. Thin-film cadmium telluride (CdTe) PV modules consistently achieve the best environmental performance, while multicrystalline silicon (mc-Si) modules are associated with the highest emissions. For instance, the CO 2 emissions per cubic meter of produced water decrease from 7.73 to 3.04 kg when thin-film CdTe PV modules are used instead of monocrystalline silicon (sc-Si) modules. The results show that flat plate collectors (FPC) perform slightly better environmentally, with reductions ranging from 1 % to 11.4 % compared to evacuated tube collectors (ETC) across several impact categories. • Four solar-powered VMD configurations were environmentally assessed using a cradle-to-gate LCA. • The solar VMD system with mechanical vapor compression showed the lowest energy use environmental impacts. • Solar collectors and PV modules dominate the environmental footprint of the system. • CdTe PV modules and flat plate collectors provide the best environmental performance.