We were in St. Martin for vacation. The southern part is Dutch and the northern part is French. The whole island uses desalinated water, so I've been thinking about that some more.
Here's a succinct piece from "Scientific American" on desalination: Why don't we get our drinking water from the ocean by taking the salt out of seawater? It turns out that many do: "The International Desalination Association says that as of 2007 there were about 13,000 desalination plants operating around the world. They pumped out approximately 14.7 billion gallons (55.6 billion liters) of drinkable freshwater a day." But why don't we use more? The short answer is energy. It's an energy-intensive process. My answer? Use renewables.
I've referenced the very exciting Desertec project here a few times. The concept is to provide a very significant bit of Europe's electricity and most of North Africa's from solar power from the Sahara. I mentioned it here last month in the context of the "SuperSmart Grid." It's an exciting prospect: the idea of supplying virtually limitless amounts of power from solar arrays in the Sahara Desert. See the Trans-Mediterranean Renewable Energy Cooperation (TREC) project. See also this informative UK website on this concept. Solar power for massive desalinization projects? Why in the world not? See this recent article from "The Guardian" too.
I talked to the manager of the beach resort where we stayed. I wanted to pitch renewables to him: sun, wind, ocean power. It turns out he was on it. They are well along in researching and deploying a big PV arrangement. Since they also have a reverse osmosis plant for the hotel, the solar arrays would presumably help power that.
For another perspective on desalination and freshwater use, see this from the Pacific Institute where Peter Gleick, the author of the short "Scientific American" piece, is president.
Now don't go away because while we're on the subject of desalination, here's another angle: use seawater in an industrial process that takes waste heat and carbon dioxide from power plants to make cement. The seawater is stripped of calcium and magnesium making it ideal for desalination technologies, according to this exciting article, also from "Scientific American." One of the companies referenced in the article, Calera, claims that it can take more than 90% of the carbon dioxide from power plant emissions to, for all intents and purposes, sequester it in concrete. This company and some others are working now to pilot this process.
It's one more hugely exciting prospect for getting to the zero-carbon society that we have to realize, and sooner rather than later.