As seen in the most recent “Friday Facts”, the amount of fresh water that is easily accessible and safe for consumption makes up a tiny fraction of the total volume of water on earth. In fact, roughly 97% of all water is in the form of the salt water found in our massive oceans. Considering that an increasing world population needs fresh water not only to drink but also to make the varied array of mass-produced goods we consume, the relative scarcity of water is set to become even more problematic. Indeed, as a New York Times article pointed out the other day, renewable energy can use major amounts of water to run efficiently and economically. In concentrated solar thermal solar power “reflected sunlight heats a fluid flowing through…tubes. The hot fluid then is used to boil water in a conventional steam-turbine generator to produce electricity” (quote from NREL). In order to be recirculated, water is used to cool that “working hot fluid” that was originally heated by the concentrated sun. This is especially true for parabolic trough technology (though “dry cooling” is being developed). This need for large amounts of water is a major potential drawback as many of the large solar installations are, of course, in deserts and in places like California where the population is large and water is already scarce. How will we cope with increased demand on our very limited water supply while undertaking the necessary shift to potentially water hungry renewable sources of energy?

One answer may be desalinization. Though often decried for the large amount of energy needed to separate out the salt, technological progress has made the desalinization process less energy intensive and less costly to preform on a large scale. Reverse osmosis is becoming the preferred method of desalinization, as opposed to thermal evaporation. In reverse osmosis, the membrane through which only water molecules are pushed (leaving behind the salt) has improved enough to generate energy savings over earlier generations. While this is a nice improvement, there is still some concern over what the impact of dumping the leftover water (now twice as salty) will be on the local marine ecosystem.

It appears, however, that desalinization will play an ever more important role in getting us the water we need. As the technology improves, costs will come down and the impact on nature will be minimized. Given the rise in the cost of freshwater (due to the exhaustion of close and easy to develop sources) and the 4% per year reduction in desalinized water costs, Fortune states that the costs of both sources are now about the same. There are over 13,000 desalinization plants worldwide (some 1,500 in the U.S.) and the $30 billion industry is expected to double in capacity by 2016. Considering that 1,857 gallons of water are needed to produce a pound of beef, 20 gallons for a glass of beer (not for New Belgium, though), 1,989 for a pound of leather (possibly overlapping with beef production), and 11 for one slice of wheat bread, we are going to need all the water we can get.

– Justin Manger

(The numbers on gallons of water needed to produce certain goods as well as other stats were taken from a Fortune article on desalinization that is currently not online and only in the paper version).

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