Desalination: A Solution to the Looming Water Crisis

Water is a resource that many in the developed world take for granted. A quick turn of the tap yields an endless supply of clean, drinkable water. Yet, this isn’t the reality for billions of people globally. Rapid population growth, urbanization, and increasing water consumption by agriculture, industry, and energy sectors have left a growing number of countries grappling with water scarcity. As the global population is projected to rise to 9.7 billion by 2050, the need for sustainable freshwater sources has become increasingly urgent.
Water scarcity is expected to intensify, with a potential 40% global shortfall in freshwater resources by 2030, threatening not only communities but also food production and economies. The World Resources Institute estimates a staggering 163% increase in water demand by mid-century in Sub-Saharan Africa alone, outstripping available supply and raising the prospect of severe shortages. However, despite the daunting scale of the problem, an emerging solution offers hope: desalination.

The Promise of Desalination
Desalination, the process of removing salt from seawater to produce freshwater, could provide a sustainable answer to the world’s growing water needs. With oceans covering nearly two-thirds of the Earth's surface and containing 96.5% of its water, harnessing this resource seems like a logical step toward addressing water scarcity. While desalination alone may not be a panacea, it can play a critical role in ensuring clean, safe drinking water for billions.
The two primary desalination methods are reverse osmosis and multistage flash distillation. Reverse osmosis is more energy-efficient and uses a semi-permeable membrane to filter salt and impurities from seawater. In contrast, multistage flash distillation uses steam heat and pressure variations to evaporate water, leaving behind salty brine. Both methods create usable freshwater, though they require substantial amounts of energy and produce brine, which can harm marine ecosystems if not managed properly.

Innovations in Desalination Technology
One of the key challenges in desalination has been its high energy consumption, traditionally powered by fossil fuels. However, recent innovations are reducing the energy and environmental costs associated with the process.
Wave-powered desalination, as developed by Oneka Technologies, is a prime example of how renewable energy is transforming this field. By using floating buoys tethered to the ocean floor, the system harnesses wave energy to drive the desalination process. This innovation eliminates the need for fossil fuel-based power and reduces the carbon footprint of traditional desalination plants. Additionally, these wave-powered systems require 90% less coastal land than conventional plants, making them less intrusive to local ecosystems.
Solar-powered desalination is another promising development. Researchers from King’s College London, MIT, and the Helmholtz Institute have pioneered a method that uses specialized membranes to separate salt ions from seawater using solar energy. Dutch start-up Desolenator has taken this concept further, offering a fully circular, solar-powered desalination system. This technology avoids harmful chemicals and produces up to 250,000 liters of freshwater daily, with zero liquid discharge. Desolenator’s mission is to provide water security to communities and businesses in water-scarce regions without exacerbating environmental degradation.

The Economics of Desalination
While energy efficiency has improved significantly, desalination remains expensive compared to traditional water sources. Reverse osmosis, the most widely used desalination method, now requires around 3.5 kWh of energy per cubic meter of water, down from 20 kWh in the 1970s. Some projects, like Israel’s Sorek B plant, have driven down costs to $0.41 per cubic meter, making desalination a more viable option.
Despite this progress, the widespread adoption of desalination is hindered by high capital investment and operational costs. In regions like the United States, providing all domestic water through desalination would increase household electricity consumption by about 13%. In lower-income countries, this figure would be even higher, making desalination impractical for many rural or energy-poor communities.
However, desalination’s affordability improves dramatically when focusing on the most essential need: drinking water. Providing the World Health Organization’s recommended 50 liters per person per day would require an additional 511 TWh of electricity globally, about 1.7% of the world’s current electricity production. The cost of producing enough drinking water for one person for an entire year is a surprisingly low $2.30, less than the price of a single bottle of water in many countries.

Desalination in Agriculture: Still a Challenge
While desalination shows great promise for providing drinking water, its use in agriculture is more problematic. Agriculture accounts for around 70% of global freshwater withdrawals, making it one of the largest consumers of water. However, the high cost of desalinated water makes it unsuitable for irrigating staple crops like wheat and maize, where water costs would far exceed the value of the crops themselves.
For instance, producing one kilogram of wheat requires about 650 liters of water. Using desalinated water for this purpose would cost more than three times the current market price of wheat, making it economically unfeasible. Desalination might have a role to play in high-value crops or in areas where indoor farming techniques can reduce water usage, but it is unlikely to provide a large-scale solution for agricultural water demand.

Desalination’s Role in Averting a Water Crisis

As climate change accelerates and populations grow, the world is facing an impending water crisis. Desalination, with its ability to transform abundant seawater into drinkable water, offers a critical lifeline. However, to fully unlock its potential, continued innovation is needed to lower energy consumption and environmental impact.
Wave and solar-powered desalination technologies are already proving that desalination can be both sustainable and cost-effective. As these technologies mature and scale up, desalination could become a key tool in preventing water shortages, especially in regions already experiencing water stress. While not a silver bullet, desalination will undoubtedly play a central role in the global effort to ensure water security for future generations.
In a world where access to freshwater is becoming increasingly limited, desalination may be just the lifeline we need to combat water scarcity.