Every year, Saudi Arabia's farmers use 21 cubic kilometres of water, pumped to the surface from the country’s fossil aquifers, a non-renewable resource found deep underground.
This may sound like a lot, by comparison the country's households use up 3.5 cubic kilometres a year. Ethiopia's Gerd dam, currently under construction, could hold 74 cubic kilometres of water if fully filled, which will mainly be used for hydroelectric power generation.
So, just how much water does a growing arid nation need?
Under Saudi Arabia's plans to diversify its economy, the country will need vast quantities: the Red Sea tourism project, the most ambitious of its kind in the world, will need an estimated 50,000 cubic metres of water a day at least.
This is a critical challenge, so it is no surprise the government has blazed a trail investing in new technology to desalinate seawater.
The desalination revolution
Saudi Arabia, the UAE and Israel now receive more than half their water through this technology and invest significant resources in trying to make it more efficient.
Prior to this, the situation for water-stressed countries was looking bleak, but desalination offers a chance for more arid countries to address water shortages, at least partially, now that the cost of the technology is falling.
Seawater desalination was once too expensive to be viable – in the 1960s it cost $10 per cubic metre - but that cost has come down to as low as 50 cents per cubic metre, or even less.
This means it is no longer the preserve of wealthy countries.
“Ten years ago, the view of desalination was that it was a rich Arab state solution," says Nizar Kammourie, chief executive of Sawaco, one of the leading desalination companies in Saudi Arabia.
“But this exclusive club has grown and you now have Spain, Australia and many US states involved. But even the largest plant in the US, the Carlsbad desalination plant in San Diego, which produces about 220,000 cubic metres a day, qualifies as medium-size in the Gulf. Everyone thought it was unsustainable but now it is seen as the only viable solution,” he says.
Saudi Arabia is now a global leader in this technology, which is good news for everyone, especially millions of people worldwide who live in arid, coastal areas: as with most technology, more investment eventually leads to lower cost.
Saudi Arabia now has the largest plants anywhere in operation: the Al Jubeil plant produces 1.4 million cubic metres per day.
Advances in desalination mean that in arid coastal cities such as Basra, Iraq, seawater desalination is now within reach, although Hartha, a major project in Iraq, is behind schedule amid a series of corruption allegations.
Even as recently as 10 years ago, amid war and uncertain oil revenue, the idea of a desalination plant in Iraq was unthinkable due to cost.
Until recently, the technology has presented an environmental challenge for oil-rich countries.
Previously, the most common method of desalinating water involved burning hundreds of thousands of barrels of oil a day in thermal power stations and using excess heat to separate freshwater from salty brine.
The other common method involves membranes with microscopic holes to separate water from salt using reverse osmosis.
Both methods are costly, although membrane technology is advancing, with some firms planning to use advanced materials such as graphene.
Both methods also come with an environmental cost such as the disposing of extremely saline brine, which can affect maritime life, and a large carbon footprint.
But innovations, for example, using solar power and more efficient membranes, create less brine and use less energy.
“A lot of this came down to energy cost. It used to typically require 7-8 kwh per cubic metre in thermal desalination. But now that is 3 kwh in megaplants or even 2.5 kwh. If you couple this with solar it’s a real sustainable solution,” Mr Kammourie says.
“We’ve been doing desalination with renewable energy, partial solar solutions. Real life experiments using all reverse osmosis tech. The biggest advancements are with membranes that can deal with higher salinity. But so far that’s been incremental progress, not disruption.”
The solar domes of Neom
Through 2019, Solar Water chief executive David Reavley took no less than 18 flights to the Middle East, firming up a project to install revolutionary new technology in a completely new city: Saudi Arabia’s vision for a futuristic desert metropolis, known as Neom.
His company’s Solar Dome invention uses concentrated solar power - technology which already exists – to evaporate seawater inside a giant dome, separating fresh, drinkable water from extremely saline brine.
“We’ve taken this concept to an industrial scale and will be able to produce millions of cubic metres per year,” he says.
“From concept it took about two and a half years to develop into a situation where there was a sufficient volume of water that could be produced,” says Mr Reavley.
Work to treat water on an industrial scale was undertaken with a team from the UK’s Cranfield University.
“And that water from the dome will be drinking water quality, meeting [World Health Organization] guidelines, although for domestic use it would be remineralised,” he says.
With any desalination process, minerals that naturally occur in freshwater - from rain or rivers - have to be added later. This is because desalinated water is slightly acidic and can accelerate corrosion without adding minerals such as calcium, which washes into freshwater from rocks.
“It’s not giving off pollution, it’s aesthetically pleasing to look at, it’s not ruining the horizon like a massive conventional power plant,” he says.
Mr Reavley says the technology can be adapted to multiple settings, from providing water to a coastal hotel to water for heavy industry, such as a project they are looking at in Jordan for the country’s fertiliser industry.
Sustainability has become a central theme of the Neom city concept.
“Work has started, a site has been designated and construction will be starting shortly,” Mr Reavley says, adding that the pandemic may impact the timeline.
"Components are being manufactured, the designs and blueprints are fully completed for the site.”
Perhaps the most striking thing about the idea – if fully realised – is the apparent cost: just $0.34 cents per cubic metre.
“We’re now getting inquiries from all over the world, most recently in California. There’s no shortage of interest, it’s just a question of being able to get on a plane.”
“Through 2020 we were able to negotiate contracts in Jordan for work at phosphate mine sites. And we are talking about projects in Egypt. It has been slower than we would have liked,” he says.
Despite facing similar delays, Mr Kammourie of Sawaco is also optimistic about the future.
“We’re seeing huge investment," he says.
As evidence, he points to Sawaco's partnership with Saudi Arabia's water and energy firm Acwa Power on the desalination plant Rabigh 3, expected to come online by the end of 2021.
It also partnered with Gradient, a US company, in 2014 to work on new technology that puts less brine into the sea, a challenge the company has been trying to tackle since 2008.
"You have to innovate. Costs and margins are falling and that comes from innovation," says Mr Kammourie.
But is the idea of sustainably turning seawater into drinking water a dream?
“It’s smart and disruptive,” he says.