Will desalination solve the water crisis?

This is another entry in a series answering questions from curious donors, website visitors, and casual commenters.

As we’ve said before, it can be difficult for those who have always had water piped into their homes to understand what it’s like not to have water. We haven’t needed to trek long distances, brave harsh wilderness, wait in long lines, or dig scoop holes to obtain water. 

But the water crisis isn’t always straightforward. It is massive, nuanced, and ever-changing.

Our staff in the United States and overseas in our target areas live and breathe water, sanitation, and hygiene—yet we still learn new things daily. This series aims to share what we’ve learned with anyone skeptical, curious, or thirsty (get it?) for knowledge.

We’ve been asked why The Water Project is not working in desalination a few times. After all, the process of converting saltwater into freshwater is already replenishing Earth’s dwindling water resources — why not in sub-Saharan Africa? 

Desalination (sometimes shortened to “desal”) takes advantage of the fact that the vast majority of the world’s water is saltwater. And with 44% of the world’s population living near an ocean coastline, many think desalination could be an easy way to supply humans with fresh drinking water.

There are now over 22,000 water desalination plants worldwide, a number that has been growing exponentially since the 1980s when technological advances made desalination more efficient. Most of the world’s desalination plants are concentrated within the Middle East, USA, Australia, China, Central Europe, the Mediterranean Region, and Japan.

With the world’s population booming and people using more water than ever, Earth’s freshwater resources are disappearing faster than the water cycle can replenish them. 

But as the technology currently stands, desalination is costly and problem-prone.

Desalination is still expensive in terms of both money and energy. Because renewable energy sources are more costly, many of the world’s desalination plants use non-renewable energy.

“Many Middle Eastern plants…use older thermal plants that run on fossil fuels. As a result, desal plants are currently responsible for emitting 76 million tons of CO² each year. As demand for desal is expected to increase, global emissions related to desal could reach 400 million tons of CO² per year by 2050.”

Columbia Climate School

Before the 1980s, 84% of desalination used the thermal distillation method, which requires boiling the salt out of the water in stages. As anyone who’s waited for a pot of water to boil will tell you, boiling water, especially at high volumes, takes a lot of energy.

Today, 70% of desalination plants employ reverse osmosis, which may sound familiar to anyone who drinks filtered water. Explained simply, this process involves pushing salt or brackish water through membranes that trap salt and other impurities.

Even though reverse osmosis is more efficient, it is not perfect. Desalination plants suck seawater in for treatment through pipes; this sometimes traps microscopic aquatic life like plankton and can harm larger organisms. The membranes used spoil eventually and need to be disposed of in landfills. This process also produces concentrated saltwater in the form of brine, which also needs somewhere to go.

All these costs may be worth the trouble if the output is high enough. The US’s largest desalination plant in Carlsbad, California, creates nearly 50 million gallons of water daily, providing a potable water supply for approximately 400,000 people. 

Desalination is a last resort when other freshwater resources disappear, especially for nations that are landlocked, lack wealthy/high-capacity governments, or lack an already-implemented water distribution system. 

Several desalination companies have made inquiries about constructing plants in sub-Saharan countries, but their biggest implementation challenge has, unsurprisingly, been funding. 

For instance, one planned desalination plant for Mombasa, Kenya has been stuck in the financial development stage since 2018. The Mombasa plant plan includes the desalination parent company’s involvement for 25 years, which prompts questions about what might happen to the plant once that term is up and high operational costs fall on the Kenyan government’s shoulders. 

“Challenges to the widespread adoption of desalination exist, such as expense, significant energy use, the need for specialized staff training, the large carbon footprint of facilities, environmental issues such as greenhouse gas emission (GHGs), chemical discharge, and operational problems such as membrane fouling.”

membranes

In our work, we encounter abandoned water projects all the time — from well-meaning people thinking they’re providing long-term solutions without fully understanding the problems they’re hoping to solve. Hardware on water projects breaks down frequently, and it takes constant monitoring and oversight to ensure that water sources remain safe and reliable for human use. 

If you think about it, a desalination plant is just a massive water project — one that costs millions instead of thousands. Our projects are smaller, which makes them easier to plan, monitor, and maintain.

 “In the areas we work, desalination is too complex a system to reliably keep online,” said Emma Kelly, Program Manager at The Water Project. 

“First, there are major supply chain concerns when trying to import parts for a system with that quantity and complexity of parts. Second, our programs are sustainable because we also work directly with communities, governments, and private businesses to build their long-term capacity for maintenance and repair. The Water Project continues to actively monitor and maintain our water points, but we would not want to build anything that the local governments and communities would not eventually be able to maintain themselves.”

While the global freshwater crisis intensifies and the powers that be sort out large-scale solutions, there are still billions of people who live without clean, accessible drinking water now.  

The Water Project has modeled its structure so that average people like you and me can see themselves as part of the solution. When we hear about numbers like “billions,” our brains shut off, because: “I’m only one person — I can’t help billions of people. Whatever I donate will be just a drop in the bucket.” 

But at The Water Project, when you sponsor a community, your donation builds one water project for one group of people — which, collectively, becomes part of an ever-growing whole. Not only is this process easier for donors to wrap their heads around, but it’s also nimbler. We get people the water they need faster than billion-dollar projects stuck in financial limbo. 

And because we closely monitor groundwater reserves in our service areas, we know our ecological impact is minimal. 

“The Water Project is constantly trying to improve the services we provide, especially in terms of sustainability,” explained Emma Kelly. 

“Our recent collaboration with The Water Institute at UNC Chapel Hill has empowered us to model and track the groundwater levels in Kakamega and Vihiga Counties in Western Kenya. This collaboration highlighted new groundwater indicators that have been incorporated into regular monitoring and will inform decisions about where to place new wells to ensure they will not cause over-extraction.” 

All in all, desalination is outside of The Water Project’s work area. We aim to help people currently suffering from water scarcity in sub-Saharan Africa, where desalination is not yet established. We’re thankful for all the donors who help us in this mission — and for everyone who reads our blog to learn more about the water crisis and the world.