Wired for water: How electrification is transforming desalination

Historically, thermal desalination technologies - such as multi-effect distillation (MED) and multistage flash (MSF) - dominated MENA, primarily using natural gas (and some oil, especially in Gulf countries) for thermal processes, plus electricity for pumping and treatment. Elsewhere, nearly all new capacity since 1970 has been reverse osmosis, partly due to higher fossil fuel prices, even if capacity only picked up in later years, when the technology became more efficient and cost-effective.

Thermal plants are highly energy-intensive, using up to ten times more energy (around 250 MJ/m³) than reverse osmosis for the core desalination process. Including intake, treatment, brine disposal, and controls, thermal plants typically consume 7 to 14 MJ/m³ (around 2-4 kWh/m³) of electricity, while seawater reverse osmosis uses 9 to 22 MJ/m³ (around 2.5-6 kWh/m³) for the core desalination and other steps combined, with brackish water desalination and modern state-of-the-art plants requiring even less. For context, a household relying entirely on desalinated water from thermal plants consumes as much energy weekly as a full car tank of gas.

In the Middle East and North Africa, in recent decades, electricity-powered membrane technologies (especially reverse osmosis) have quickly gained share. The last major new thermal plant in the region was added in 2018 in Qatar. Reverse osmosis and other membrane-based plants now account for over 60% of installed capacity in the region and more than 80% globally, doubling electricity consumption for desalination since 2010.