Global applicability of solar desalination

Over-exploited fresh water resources, fossil-fuel depletion and climate change all highlight need fordesalination powered by renewable energy. This study briefly reviews literature on solar desalinationtechnologies and examines economic and environmental feasibility. The maturest technology appears tobe reverse osmosis driven by photovoltaics. Many studies refer to apparent spatial coincidences of waterscarcity, solar energy abundance and saline water availability, but none examine the phenomenonobjectively from a global perspective. This study proposes a method for correlating international data onwater scarcity and stress, saline water resources, and insolation levels, to calculate rank scores (0 � R � 1)which identify where solar desalination is most applicable. Low scores (R <0.125) occur in landlockednations with limited saline groundwater resources (Nepal, Bolivia, South Sudan) and near polar regionswhere fresh water is abundant and solar insolation levels are low (Canada, Russia and Scandinavia). Highscores (R > 0.422) occur in 30 nations, including Middle Eastern and North African countries where fossilfuelled desalination is commonplace, and solar desalination has obvious applicability. The analysisidentifies 28 further countries (including parts of USA, China, India, Indonesia, Australia, and countriesthroughout Africa, Asia, South America and Europe) where 0.273 <R <0.422 scores indicate that other,less obvious, solar desalination opportunities exist.