As climate change intensifies, the growing scarcity of freshwater is prompting renewed interest in desalination—the process of removing salt from seawater or saline groundwater to produce potable water. While the planet is covered by water, only a small fraction is suitable for drinking, and rising temperatures coupled with more frequent droughts threaten to increase pressure on existing water supplies.

Several Middle Eastern countries have already invested heavily in desalination technology, with some sourcing up to half of their drinking water from such plants. This reliance has drawn international attention, including reports of attacks on desalination facilities during regional conflicts and political rhetoric threatening similar actions. In contrast, the United States currently derives about 1 percent of its drinking water from desalination, although the number of plants is growing, with over 400 facilities operating nationwide.

A major barrier to broader adoption of desalination has been its high energy consumption, leading to elevated costs and significant carbon emissions. However, advances in solar power have sparked enthusiasm for solar-powered desalination as a potentially transformative solution. Researchers suggest that seawater desalination, especially when coupled with renewable energy sources, could alleviate water shortages in up to half of coastal cities globally and extend benefits inland by tapping into saline groundwater.

Despite widespread optimism, experts caution against viewing desalination as a panacea. Independent consultants and researchers underscore the persistent complexity and costs associated with scaling desalination technology. Many claims about dramatic cost reductions are often limited to small-scale operations, which do not translate easily to the volumes needed for large urban centers.

Solar desalination employs various methods, including thermal techniques that use solar heat to evaporate and condense water, and reverse osmosis systems powered by solar-generated electricity. Yet deploying large solar arrays adjacent to major desalination plants presents logistical challenges, as these facilities require coastal locations where land is costly and contested. One study forecasted that fully powering Israel’s desalination plants through on-site solar panels would necessitate land comparable to two-thirds the size of Tel Aviv.

Therefore, most large facilities rely on electricity from regional power grids, with renewable energy inputs distributed throughout the system rather than directly at the plant site. While integrating solar power into the grid may modestly reduce electricity costs, the overall impact on desalination expenses remains unclear and subject to regional variations in energy supply and fossil fuel prices. Battery storage improvements could enhance solar’s competitiveness, but construction and maintenance costs of plants remain substantial, often making desalination projects 30 to 50 percent more expensive than alternatives like wastewater recycling or stormwater capture.

Desalination may hold particular promise in off-grid or rural settings. Projects in countries such as Kenya aim to provide clean water to underserved communities where centralized infrastructure is lacking. However, even the cheapest desalinated water produced in these contexts often costs multiple times what regulated water kiosks charge, limiting accessibility for low-income populations. In some instances, plants primarily serve wealthier customers, highlighting concerns about equitable access.

Experts also note that investing in water storage infrastructure, such as rainwater tanks, may be a more cost-effective approach in certain regions where rainfall is sufficient but storage capacity is lacking. The long-term sustainability and affordability of desalination will likely depend on balancing technological innovation with investments in conservation, storage, and diversified water sources.

While desalination is not a silver bullet, the urgency of projected water shortages due to climate change suggests it will play an increasingly important role in securing future water supplies. As one researcher put it, despite the high price of desalinated water, the cost of scarcity may be far greater.