Water Desalination Using Renewable Energy

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Water Desalination Using Renewable Energy

This brief focuses primarily on water desalination based on the use of renewable energy, i.e. renewable desalination . Global water withdrawals amount to around 4,000 billion m3 per year and in some regions – especially the Middle East and Northern Africa (MENA) – desalination has become the most important source of water for drinking and agriculture.

Today’s global desalinated water production amounts to about 65.2 million m3 per day (24 billion m3 per year), equivalent to 0.6% of global water supply. The MENA region accounts for about 38% of the global de-salination capacity, with Saudi Arabia being the largest desalinating country.

Major desalination technology options are based on thermal processes using both heat and electricity, and membrane technologies using electricity only. The dominant technology is Reverse Osmosis (RO), which accounts for 60% of the global capacity, followed by Multi Stage Flash (MSF), with a 26.8% share.

The larger desalination plants can reach a capacity of up to 800,000 m3 per day or more. Renewable energy can play an important role in desalination. Renewable technologies that are suited to desalination include solar thermal, solar photovoltaics (PV), wind, and geothermal energy. Solar technologies based on solar heat concentration, notably concentrating solar power (CSP), produce a large amount of heat that is suited to thermal desalination.

Pho-tovoltaic and wind electricity is often combined with membrane desalination units (reverse osmosis, electrodialysis). As electricity storage is still a chal-lenge, combining power generation and water desalination can also be a cost-effective option for electricity storage when generation exceeds demand.

Thiss brief is available for download from the following IEA-ETSAP and IRENA sites