Cheap, efficient desalination

Large parts of the world are increasingly under water stress, with freshwater availability for drinking and agriculture shrinking, even as global demand rises. The International Water Management Institute projects that nearly two billion people could be in situations of physical water scarcity in the coming decade.

The world has no shortage of water. However, 96.5 percent of the world’s water is saltwater in the world’s oceans while just 1.2 percent is freshwater available on the surface.

Source: Igor Shiklomanov's chapter in Peter H. Gleick, 1993, Water in Crisis: A Guide to the World's Fresh Water Resources.

Desalination is the process of converting saltwater to freshwater. Desalination has existed for centuries but has historically been extremely energy-intensive and costly. Yet advances in reverse osmosis technologies have reduced the energy required for water desalination by roughly a factor of ten since 1970.

Desalination now requires a small fraction of the energy required in previous decades. Source: Ramez Naam, The Infinite Resource

New advances in membrane technology and nanomaterials will continue to reduce the energy cost and increase the speed of desalination. At the same time, technological learning will reduce the capital cost of desalination plants by roughly 15 percent per doubling of industry scale. Combined with lower-cost energy from solar and other resources, these advances will continue to lower the cost of desalination, making it cost-effective as a replacement for municipal water in coastal regions.