The Largest Desalination Plant in Saudi Arabia: 9 Key Facts!

Riyadh, The capital of Saudi Arabia at night

To truly appreciate the scale of commercial desalination it helps to think about how long it takes to boil a saucepan of water until everything has been evaporated as steam, quite a long time right? I have always marvelled at how desalination techniques have been refined to the point that they can supply entire cities with water. Saudi Arabia being a large country in an extremely arid environment, made me think about what is their biggest desalination plant and how they make it work.

Ras Al Khair is the largest desalination plant in Saudi Arabia and the second largest worldwide! The plant produces a staggering 1,036,000 m3/day, over 400 Olympic-sized swimming pools! Located in Saudi Arabia, Ras AL Khair is the primary water source for the capital city, Riyadh.

The Ras Al Khair desalination plant is a considerable feat of engineering and has some very impressive statistics related to its construction, technology and its importance to the surrounding area and the whole of Saudi Arabia. Nine impressive statistics about this facility are highlighted below.

It produces up to 1,036,000 m3/day of freshwater

The Ras Al Khair produces a truly staggering amount of water each day. 1,036,000 m3 of fresh water or to help wrap our minds around that quantity: Over 414 Olympic-sized swimming pools! Luckily the plant draws water from the Persian Gulf where it is situated so it has a near-infinite amount of source water to rely upon. It is the second largest desalination facility worldwide, with only Jebel Ali Power Plant and Water Desalination complex in Dubai having a larger daily production!

I wrote an article The 10 Largest Desalination Plants In The World which is worth a read if you are curious about the scale of desalination present in the world today.

The water is piped 535km to Riyadh

The 500km pipeline itself is a feat of engineering.

The location of the plant has to be noted in that it lies over 500km away by car from its final destination of Riyadh. The pipeline that transfers the water from Ras Al Khair to Riyadh is an engineering feat in itself, a 72-inch diameter steel pipe transporting 414 Olympic swimming pools of water 535km to Riyadh daily. This feat of engineering was completed in 2015 by the Turkish Engineering firm Limak Group

It produces approximately 1554 m3 of waste daily

A rather stark figure that hurts the desalination plant’s environmental credentials is the amount of waste produced, approximately 1.5 litres of saline brine is produced for every 1 litre of drinking water. Currently, this brine is released back into the Persian Gulf, however, there are plans to exploit the concentrated brine economically. Being highly concentrated in Magnesium and Sodium Chloride, plans are underway to set up extraction facilities that will provide both an economic benefit along with a reduction in waste produced from the plant.

Ras AL Khair is operated by 3500 people

The desalination plant employs a staggering amount of people.

Built as a part of the Ras Al Khair Industrial City with loans from the Saudi Industrial Development Fund (SIDF), the facility now employs 3500 people both directly and indirectly. This industrial project was one of the many projects undertaken since 2010 as a path to spur economic development and reduce Saudi Arabia’s dependence on the oil and gas industry for government revenue.

It utilizes both distillation AND RO desalination

The Ras al Khair plant is rather unique in that it utilizes both of the most common and efficient desalination techniques: Distillation and Reverse-Osmosis (RO). The general breakdown of the plant is: eight multi-stage flash distillation (MSF) modules and 17 RO modules. The MSF modules produce 70% of the daily output with the RO modules producing the remaining 30%. If you are unsure about what RO and MSF desalination is I wrote an article with concise explanations here: What Are The 5 Different Desalination Types?

Prior to being formally desalinated by the RO modules the seawater gets pumped in from the Gulf and goes through a preparation process where it undergoes a combination of flocculation, coagulation, sedimentation and various levels of filtration. This preparation process is designed to increase the efficiency of the RO process and maximize the output whilst minimizing damage to equipment.

It cost $7 billion USD to build

The entire project came in at just over seven billion US dollars by the time it was completed. This staggering investment was by far the largest that anyone had put towards a desalination facility. The project’s completion represented a significant milestone in showing that desalination represented a viable solution to the water crisis, particularly in extremely arid environments like the Middle East.

It has its own power station!

Ras Al Khair has its own thermal power station to produce electricity for the plant.

The Ras Al Khair plant also has its own power station within the same setup and there are certain synergies between the two that make it a profitable partnership. The Ras Al Khair gas-fired power plant puts out 2400MW of power and would normally require a whole lot of water to cool the turbines down. On the other hand, the multi-stage flash distillation portion of the desalination plant requires huge amounts of energy to heat the water to the point of evaporation so that the steam can be collected.

The combined facility really takes advantage of both the needs of the power plant for cool water and the desalination plant for a source of heat. A synergy is created where the desalination plant’s source water is first used to cool the power plant and in the process, it heats up from the turbine excess heat before entering the desalination process. As the water now enters the desalination system at a higher temperature than would be achieved if pumped directly from the ocean, less gas is required to heat the water. This clever piece of engineering allows considerably less energy to be used than if the power plant and the desalination unit were separate entities.

This clever piece of engineering allows considerably less energy to be used than if the power plant and the desalination unit were separate entities.

It serves 2.9 million people

Perhaps the most impressive statistic of all, the Ral Al Khair desalination plant provides enough fresh water to sustain the lives of around 2.9 million people. This figure is calculated from the Kingdom of Saudi Arabia’s water use statistics where each resident of Riyadh uses 357 litres of water per day which when divided into the daily production comes to 2.9 million, a seriously impressive engineering achievement.

It is still owned by the Saudi Government

The Saudi Arabian government did try to sell a portion of the Ral Al Khair desalination plant in 2017 for $2 billion USD, a considerable discount from the $7 billion USD price tag for construction, it was, however, called off in 2021. The reasoning behind the discounted sale was a privatization push from the Saudi government known as “Vision 2030” to raise funds for future investment opportunities. The Saudi Government has not ruled out putting the facility up for sale again in the future.

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