Synergies and potential of hybrid solar photovoltaic-thermal desalination technologies

Solar desalination has emerged as a sustainable solution for addressing global water scarcity in the energy-water nexus, particularly for remote areas in developing countries. How to use the light spectrum through solar devices can profoundly affect the solar energy utilization, desalination rates, off-grid applicability, and water affordability. Solar photovoltaic (PV) and solar thermal (ST) respectively have enabled a variety of interesting solar desalination technologies, but the resulting applications usually limit the integration between solar and desalination to be either electrically or thermally connected. Here this review paper explores smart co-uses of heat and electricity from the sun to improve the efficiency, productivity, and independence of various solar desalination processes. It is found that coupling solar photovoltaic-thermal (PVT) with desalination could be a practical and immediately deployable route for plausibly more sustainable solar desalination than current solutions, because the combined electrical and thermal energy outputs from PVT panels could be used synergistically to catalyze the improvement on the solar energy efficiency, specific energy consumption, and specific water production, as well as the operational inde-pendence for off-grid applications. Our preliminary analysis indicated an up to 20 % lower cost of PVT-desalination than current solar PV-desalination and ST-desalination but also with challenges discussed.