Desalination, The Future of Fresh Water?
Challenges in desalination reflect the decarbonization of other industries, but it is a widely accepted technology that is overcoming environmental hurdles.
(A quick shout-out to my brother-in-law, who has asked me about this topic numerous times.)
97% of the earth’s water is saltwater in oceans and seas. Of the 3% that is freshwater, only 1% is available for drinking, with the other 2% frozen (for now) in the polar ice caps.
I don’t see a ton of news about the desalination industry. Yet, it has become one of those almost ‘assumed’ parts of every industrial or infrastructure project. Most industrial processes require fresh water to some degree, yet there isn’t enough of it.
We hear about the limits of our water supply, the effect of climate change, and growing populations daily. But what I see is a lot of subtext that such-and-such project will desalinate water to meet its needs.
Of course, there’s a reason that the need for drinking water catches headlines. Just over half of all industry revenues are generated by municipal water projects. But that leaves a large slice of the pie going towards industrial uses.
And we use this fresh water for all sorts of things besides drinking and growing food.
“About 1,800 gallons of water are needed to produce the cotton in a pair of jeans, and 400 gallons to produce the cotton in a shirt.”
+Interesting water facts - Oldham County Water
So, between a thirsty population, thirsty food systems and thirsty industry, where is all the water coming from?
This is far from a real deep dive into desalination. Call it a medium dive (or more likely a cannonball). Still, I hope it provides a good overview of the scope of this industry, its challenges and opportunities for improvement, and some players innovating in this space.
Here’s what’s inside:
What is Desalination
Desalination Industry Trends
How it Works
Challenges - Energy in, Brine out
Big picture acceptance, local challenges
Prominent players and startups
Conclusion
What is Desalination
Desalination is the process of removing salt and other impurities from seawater or brackish water. This process creates fresh water for human consumption or industrial or agricultural use.
Desalination is not new. After all, humans have been extracting valuable salt from seawater and capturing the pure condensation for centuries.
However, the water stresses of our modern world due to use, waste, population growth, and a changing climate have pushed this industry into the spotlight.
The chart above shows global desal capacity growth through 2015. Since then, capacity has grown another 40% to 115 million cubic meters per day.
This number, in turn, is expected to double by 2050.
So, the world is increasingly turning to desalination as a tool in its battle against water scarcity. While initially a water solution for rich and dry countries with abundant, cheap energy (think Saudi Arabia, Kuwait) or small island states (expensive energy, but need water), the technology has become almost ubiquitous.
“As of early 2020, nearly 21,000 operational desalination facilities with a total desalination capacity of nearly 115 million cubic meters per day (Mm3/d) were located in at least 177 countries and territories worldwide.”
The Middle East leads the world with 53% of the total installed capacity followed by North America (17%), Asia (10.6%), Europe (10.1%), and Africa (6.2%).
+Global water desalination capacity by region - Statista
Some key industry data points:
$15.5 billion in revenue in 2022
$32 billion in revenue expected in 2030
Seawater segment was 60% of all revenue
Reverse Osmosis technology accounted for 55% of investment
52% of the market is municipalities
50% of the market is Middle East and Africa
+Water Desalination Equipment Market Size, Share & Trends Analysis - Grandview Research
How Desalination Works
As the chart above highlights, the two main existing techniques for desalination are thermal desalination and reverse osmosis desalination. The chart also shows how RO is taking over the market.
Desalination Techniques
Thermal
Thermal desalination replicates the natural evaporation process by heating the saltwater and capturing the clean evaporation. It is a relatively simple process but is far less energy efficient than newer reverse osmosis processes. There isn’t much investment or innovation in this space, but is important to know about this since these plants still exist and will continue to be run until they reach the end of their useful lives.
Reverse Osmosis
“In reverse osmosis desalination, seawater is forced through a semipermeable membrane by adding pressure in a continuous flow condition, thereby removing salt and other impurities. It is the most popular desalination method due to its independence from power plants, scalability and general cost-effectiveness.”
+The world’s thirst for desalination plants - World Pumps
Other Techniques
Other important methods include Multi-stage Flash (MSF) Distillation and Multi-effect Distillation. These methods are often used in conjunction with Reverse Osmosis in hybrid plants.
Combining technologies has been found to increase efficiency, prolong plant and equipment life, and reduce fuel use. The largest desal plant in the world, the Ras Al Khair plant in Saudi Arabia, is a hybrid plant using both MSF and RO.
+Hybrid desalination systems - Science Direct
The Process
For this quick overview of the desalination process, we’ll assume it is a saltwater reverse osmosis (RO) facility. This technology is the dominant one for now, and seawater is the most available input source.
The steps of RO desal:
Intake: Seawater is drawn into the desalination plant from the ocean through intake pipes.
Pre-treatment: Before entering the reverse osmosis membranes, the seawater undergoes pre-treatment to remove larger particles, debris, and impurities. This step may include filtration, sedimentation, and chemical treatment.
Pressurization: The pre-treated seawater is pressurized using pumps to pass through the reverse osmosis membranes. The pressure is applied to overcome the osmotic pressure and allow water molecules to pass through the membrane while leaving salt and other impurities behind.
Reverse Osmosis Membrane Filtration: Seawater is forced through semipermeable membranes, which selectively allow water molecules to pass through while rejecting salt and other contaminants. The result is fresh water on one side of the membrane and a concentrated brine solution on the other.
Product Water Collection: The desalinated freshwater is collected and further treated for any remaining impurities before distribution for use.
Brine Disposal: The concentrated brine solution, containing the separated salts and impurities, is discharged back into the ocean, often after further processing or dilution.
Desal Challenges - The Ins and Outs
While there are opportunities for improvement along the entire value chain, when it comes to desalination, concerns generally deal with the ins (energy) or the outs (brine).
The Ins - Energy & Water
Desalination is an energy-intensive process. Electricity alone can account for 50% of a plant’s operating costs.
Therefore, you see the same challenges in desalination that you do with other carbon-intensive industries. While the process has become more efficient, the energy source is still a concern.
“By 2010, Saudi desalination facilities were consuming 1.5 million barrels of oil per day, more than 15 percent of today’s production.”
+Water starved Saudi confronts desalination’s heavy toll - VOANews
Like everything else in the electrification of our economy, desalination powered by dirty energy is a dirty process. If powered by renewables, it changes the picture, so there is an industry-wide focus on a plant’s power source.
And like other industrial processes, desalination plants must operate continuously for them to work most efficiently and cost-effectively.
So, the same old issues with the intermittent availability of renewables apply here as well (necessitating battery storage, hybrid renewable-gas supplies, or both).
“It is not cost-efficient to regularly de-power and re-power desalination plants with fluctuating energy supply, and RO plants must continuously operate at minimum capacity to keep the membranes wet.”
However, in some cases this intermittency could be a benefit for local renewable energy projects.
“In some situations, it may even be more financially and energy efficient to put that generated energy toward desalination rather than store it in batteries for use later. Money can be saved by only producing freshwater when renewable energy production is high.”
+Pumped water energy storage - IEEE.org
For the most part, solar and desalination are a partnership that works well. After all, water-scarce environments are often hot and dry. They are generally good places for solar energy production.
But there is research into alternatives:
+The floating desalination machines powered by the waves - BBC
+How Desal Plants Produce Energy - Water Tech Online
+Energy positive wastewater - Veolia
The Ins - Water
Energy isn’t the only input. You need a good source of water.
However, while environmental concerns about water sourcing exist, new projects have already proven sensitive to them. For example, existing technologies and site selections have already minimized the effect of seawater intake on marine life.
And there have been advancements in intake methods that are influencing the acceptance of future projects (see Doheny project below).
The public is becoming aware of the need for desalination as part of the solution to our water issues. The environmental challenge tends not to come from water intake but from the output of the hypersaline brine produced.
The Outs - Brine
Most industrial processes have some waste that must be dealt with. In the case of desalination, it is the brine left over after the clean water has been removed. Brine is a very high-salt mixture, and its discharge can negatively affect the environment.
“In most desalination processes, for every litre of potable water produced, about 1.5 litres of liquid polluted with chlorine and copper are created. When pumped back into the ocean, the toxic brine depletes oxygen and impacts organisms along the food chain.”
+Towards sustainable desalination - UNEP
You might have noticed in the quote above that there is copper in that brine.
Stay tuned…
Brine is treated by diluting it before release and ideally pumping it far out to sea in an area with strong natural currents.
“Spanish regulations set the benchmark on brine discharge based on guidance by CEDEX (the Spanish government institute for research in civil works). This uses tolerance of seagrass to salt concentrations as a basis for defining limits (CEDEX, 2012).”
+Opportunities for impact in desalination - British International Investment
However, as mentioned above, brine also often contains some concentration of valuable resources and minerals. A lot of work has already been done to isolate these elements. Might as well grab them.
Extracting more value from the brine is an area of particular interest as it further processes the waste and adds value to this byproduct stream.
“Among all the ions existing in desalination brine, and whose industrial use is possible, sodium (Na), magnesium (Mg), calcium (Ca) and boron (B) are found at high concentrations; there are also other elements, not as abundant as previous, but highly demanded in the current industry, such as lithium (Li), rubidium (Rb), strontium (Sr) or gallium (Ga).”
+The economic value of the extracted elements from brine concentrates of Spanish desalination plants - ScienceDirect
+Turning desalination waste into a useful resource - MIT
Why Doesn’t Every City Have a Desal Plant
San Diego currently gets 10% of its water from a desalination plant in Carlsbad.
But, not every city is San Diego.
Much like any real estate investment, not all locations are created equal when it comes to desalination plants. Obviously, there is proximity to the ocean, but that wasn’t the only factor in the success of the Carlsbad facility.
What worked so well for San Diego might not work for many others. Beyond the proximity to water, leveraging existing infrastructure made for a unique business case. Primarily, the desalination plant uses the water an existing power plant is already sucking in for cooling purposes.
So, this project had two significant components: water intake and power production. The plant then dilutes the brine before discharging it back into the ocean.
+San Diego temporarily solved its water crisis by turning ocean water into fresh water. But desalination won’t work everywhere. - Business Insider
But there are local forces at play.
Just up the road from San Diego, Huntington Beach denied the approval of a desal plant. You would think it would be a no-brainer here; the same company even proposed it.
However, geological and infrastructure differences between the areas led to one going through and the other not.
Despite widespread support for desalination in general, approval is still a case-by-case basis. The California Coastal Commission would later approve a desal plant in Doheny (also Orange County like HB). But, again, some key elements overcame local environmental concerns.
One of the key elements were the local subsea topography that allowed for an efficient, environmentally friendly intake system. The other was the plan to run brine discharge through a wastewater treatment facility before discharging it.
+Here’s why the desalination plant in Doheny was approved and Huntington Beach’s wasn’t - OC Register
It’s important to note that it’s not just seaside cities looking at or using desalination. Here’s an interesting article about how El Paso, Texas uses desal to clean its brackish groundwater supplies.
+Here’s how El Paso’s water desalination works - El Paso Times
Large Players and Startups
The total market for desalination has been estimated to be around $13 billion in 2022. This is expected to grow to over $30 billion by 2030.
The companies involved in desalination are often large industrial concerns that can bring infrastructure projects across the finish line. They are involved with all forms of water and wastewater management. It makes sense that desalination is just a part of the portfolio of solutions that a company in the water industry would offer.
However, the development of the Carlsbad desal plant by Poseidon Water highlighted above shows that there is space in the industry for specialists.
Some large players in this space include:
Suez: A multinational company with a strong water and waste management presence, Suez is actively involved in desalination projects worldwide.
Veolia: Another major player in the water and environmental services sector, Veolia has expertise in desalination technologies and project implementation.
+Veolia completes combination with Suez - Veolia
Doosan Heavy Industries & Construction: This South Korean company is known for its involvement in various infrastructure projects, including desalination plants.
ACCIONA Agua: This Spanish company is engaged in water treatment and desalination projects with a focus on sustainability and innovation.
Startups
There are a ton of startups in this space looking at everything from membrane improvements to small-scale plants to energy capture.
A recent grant award to the National Renewable Energy Lab shows that developments in this space are just beginning to take off.
“From developing novel membranes that filter out undesirable residues to analyzing methods to decarbonize water and wastewater treatment, NREL is working at the forefront of providing cost-effective and sustainable alternative water sources to meet U.S. demand,” said Matt Ringer, NREL laboratory program manager.
+Research Awards To Improve Water Desalination Methods - NREL
Here are a few companies I came across as well as some investors and accelerators in the water space:
Desolenator: A startup working on solar-powered desalination technology to provide clean drinking water.
Swirltex: This Canadian startup has developed a novel membrane technology for desalination and water treatment.
Echogen Power Systems: While primarily focused on waste heat recovery, they have been exploring applications in desalination to improve energy efficiency.
Aqua Membranes: Developing next-generation membrane technology for desalination and water purification.
Solar Water Solutions: Utilizing solar energy for desalination, this startup aims to provide sustainable water solutions.
“Many times, she said, the best way to reduce the costs of a treatment technology is not to improve performance, but to reduce the manufacturing costs of a particular component.”
+Research looks to lower cost of desalination - Stanford
+Imagine H2O showcases 11 startups shaking up the water industry - Waterworld
+Desalination startup in Southwest Utah addresses world’s water crisis - KUER.org
Investors and Accelerators
XPV Water Partners: This water-focused venture capital firm invests in and supports companies addressing water challenges.
WaterStart: WaterStart is a nonprofit organization that collaborates with the investment community to fund and support water technology startups.
Using Less in the First Place
“While he welcomes developments in desalination systems powered solely by renewable energy, he says everyone should focus on using less water in the first place.”
~Chedly Tizauoi, professor of chemical engineering at Swansea University
Efficiency investments, treatment, and recycling will continue to be more cost-effective than desalination. These will be the primary efforts for places not strategically placed to use desalination.
“The water-treatment facility in Orange County, California, which purifies highly treated sewer water into drinking water and serves a similar-sized population, costs about the same — $50 million — to operate each year. Except it generates about 3 ½ times more water than Carlsbad, meeting about 35% of Orange County’s water demands.”
+San Diego temporarily solved its water crisis by turning ocean water into fresh water. But desalination won’t work everywhere. - Business Insider
But as the industry trends highlight, and the El Paso example shows, there is widespread demand for these technologies beyond the coasts.
Desalination won’t solve all of our water scarcity issues in the near future, but it is an important tool in the toolbox.
Listen and Learn
Here is a good podcast that I enjoyed while researching this article. This company OceanWell was mentioned that’s created a whole subsea desalination infrastructure technology. Will have to research more, but looks very cool.