Why the environmental impacts of a boom in desalination are too big to ignore

Independent

3 days ago

As climate change makes rains more temperamental, and groundwater levels decline, the global water desalination industry is set for a boom period.
Between 2025 and 2029, global desalination capacity is set to soar by one-quarter, shows data from Global Water Intelligence, while the value of the global desalination industry is set to increase from $15 billion in 2024 to $20bn in 2027.
The projected 2029 global desalination capacity of 150 million cubic metres per day would be enough to meet current UK water demand several-times over.
With some two billion people globally already lacking safe drinking water, and two-thirds of the world's population experiencing water shortages for at least one month per year, there are opportunities for desalination the world over. But it is in the nations of the Middle East and North Africa (MENA) - and in particular wealthy Gulf nations - where the technology has truly been embraced.
MENA is the driest region of the world, containing 16 of the world's 25 most water-stressed nations. It was in water-scarce Kuwait, which has no rivers and once was forced to ship freshwater in from its neighbour Iraq, that the first desalination plant was built in the region in 1951.
Data shows that Saudi Arabia, Morocco, Egypt, and Kuwait are set to see the biggest growth in desalination capacity over the next five years. Saudi Arabia alone has plans in place to invest some $80bn in new projects, and the Kingdom consumes around 300,000 barrels of oil per day to power its desalination plants.
MENA already accounts for around 70 per cent of global desalination capacity, and the region's largest plants are able to produce enough water to supply more than 1m people. Jordan is planning a project so large on the Gulf of Aqaba that it is set to supply enough water to meet the needs of a city of 2.5m people.
Experts are increasingly warning, however, that the environmental costs of this booming technology are too big to ignore.
The process of desalination produces highly concentrated brine as a waste product, and its disposal back into the sea in large volumes can have a devastating impact on marine ecosystems. Reports suggest that waste water can be highly toxic, while areas where the water is discharged can become marine 'dead zones'.
Christopher Gasson, from Global Water Intelligence, believes that these particular concerns have been overblown.
'The brine desalination plants produce is just concentrated seawater - it might not be nice for fish next to an outfall, but that's not dissimilar to the way that it is not nice for birds to fly through the plume of a power station cooling tower,' he says. 'With the right design the brine can be managed to minimse its impact on marine life.'
The other key environmental concern is the high energy demand of desalination plants. Desalination is already responsible for 0.4 per cent of the world's electricity consumption, but that figure becomes much higher in certain countries, such as the 10 per cent of grid electricity that desalination plants consume in Israel.
If the process is to become compatible with a net-zero future, it must be powered by renewables. But with most desalination plants lying in countries that have grown rich from oil and gas, some 95 per cent of energy currently powering desalination comes from fossil fuels, according to the International Energy Agency. In 2030, the energy required for desalination in MENA is set to be equivalent to around 80 billion cubic metres per year: A figure double the current gas production from UK North Sea gas fields.
The industry is working hard to improve the energy efficiency of plants, with new membrane technology in reverse osmosis now four or five-times more energy efficient than traditional thermal distillation methods of desalination. Gulf nations have also made big promises to decarbonise their energy systems with solar electricity - though for now they remain highly reliant on the fossil fuels that they hold in abundance.
Qatar, Saudi Arabia, Kuwait, and UAE used fossil fuels to generate 100 per cent, 99 per cent, 98 per cent, and 72 per cent of their electricity respectively in 2023 - compared to 33 per cent in the UK.
The high energy demand and associated costs means that desalination remains largely the preserve of rich countries: Something that is a problem when the majority of the world's most water-scarce, climate vulnerable nations are low income countries in Sub-Saharan Africa or small island states.
But if energy efficiency continues to rapidly improve, then it holds the possibility of becoming a solution for far more countries. Indeed, Ghana, South Africa, and Namibia have already built their first plants, while this month Senegal confirmed plans to built its own first desalination facility.