The state of desalination and brine production: A global outlook

Desalinating seawater is an expensive, energy-intensive process that releases significant amounts of greenhouse gases (GHGs) in most countries that have a very intensive CO2 electricity mix. Desalination plants generally use lots of electricity, with variations depending on the technologies employed. Thermal desalination processes, used less and less, consume more than 5 kilowatt-hours (kWh) of energy per cubic meter of desalinated water produced. By contrast, the reverse osmosis desalination process, now the most widespread, can desalinate 1 m3 of water with an average of between 2.5 and 3 kWh, the record being set by a Saudi plant at 2.27 kWh. Desalination plants in the Middle East have largely benefited from an energy mix based on fossil fuels that permit cheap desalination. Electricity consumption for water desalination increased threefold in Saudi Arabia during the period 2005-2020, reaching about 6% of the kingdom’s total electricity consumption, or about 17 terawatt hours (TWh) in 2020. It is equivalent to the annual production of a large nuclear power plant. Doubling desalination capacity will therefore boost electricity demand and associated GHG emissions if the electricity mix remains largely dominated by hydrocarbons. The demand for gas and oil to produce this electricity would also increase. Several Gulf countries are beginning to mobilize renewable energy sources, such as the Al Khafji reverse osmosis plant in Saudi Arabia, which desalinates 5 The Geopolitics of Seawater Desalination Marc-Antoine EYL-MAZZEGA Élise CASSIGNOL 60,000 m3 every day, and which is powered by photovoltaic panels. Finally, there are also power stations that operate using wave and geothermal energy. Another issue with desalination concerns the management of brines: i.e., the remaining water, heavily loaded with the salt particles that have been separated from seawater, is often released into the sea, causing increased salinity levels in coastal waters. How to improve performance along the entire water chain is the last key issue, not just at the production level. Losses in transmission and distribution networks from factories to final consumers are extremely high, reaching levels of more than 50% in most Gulf countries. 

The use of desalination seems inevitable and destined to experience a very strong expansion. It is therefore urgent for these production processes to remove their dependency on fossil fuels because the doubling of installed capacity in the Middle East by 2030 is set to lead to a significant increase in emissions, unless electricity mixes become greener, as in the UAE which has deployed nuclear power in particular. Two solutions are thus required: on one hand, the setting up of desalination plants powered by low-carbon energy sources (fields of solar panels, concentrated solar power, wind turbines, wave energy, or even nuclear power), possibly with combined cycle power plants for back-up capacity. The aim is therefore to decarbonize electricity mixes to ensure plants provide low-carbon water supplies. On the other hand, the construction of infrastructures of this kind must not replace a policy of energy efficiency, the optimization of desalination plant fleets, the search to cut losses and waste, reducing consumption subsidies as well as the collection and treatment of wastewater. Improving water sector governance and encouraging sustainable water use policies in industry, agriculture and the residential sector, are essential. Ahead of the 22-24 March 2023 United Nations Water Conference in New York, with the successful COP15 on biodiversity and with the UAE presidency of COP28, water governance, and the development of a sustainable industry across the globe, is becoming central to achieve several Sustainable Development Goals and avoid fueling additional environmental degradations, as this industry is set to boom in the coming decade.