Water is our most abundant natural resource, making up 70% of the surface of the Earth. 150,000 gallons flow over Niagara Falls every second . However, fresh and accessible water makes up less than .007% of our total water resources . Production of energy and electricity are straining our fresh water supply. Particularly, open loop energy production systems consume more water than closed loop systems. Let’s take a look at how much water is used by our energy generation processes, going from worst to best in terms of fresh water use:
- Corn-Ethanol Biomass: 1000+ gallons of fresh water/gallon of fuel produced or per 1 MMBtu (open-loop system)
- Geothermal: 700-1400 gallons of fresh water/1 MWh of fuel (open-loop)
- Nuclear: 800 gallons of fresh water/1 MWh of fuel (open or closed loop; uses the highest quantity of fresh water for any thermal power generation cycle)
- Coal with Carbon-Capture Sequestration: 800 gallons of fresh water/ 1 MWh of fuel (open or closed loop)
- Conventional Petroleum: 100 gallons of fresh water/ 1 MWh of fuel (open-loop)
- Natural Gas with Hydraulic Fracturing: 50 gallons of fresh water/1 MWh of fuel (open-loop)
- Wind & Solar: 0 gallons of fresh water/ 1 MWh of fuel 
- Algae: 350 gallons of fresh water/1 MWh of fuel produced (closed-loop), but can be used in contaminated/polluted fresh water 
However, our conventional energy generation sources are only one piece of the policy pie. While thermoelectric power generation accounts for 41% of the U.S.’s annual fresh water use, agriculture and the public use 37% and 12%, respectively . Furthermore, while this graph shows our fresh water use by percentage, the overall nominal amount of fresh water we use is dramatically increasing. With the introduction of corn ethanol as a fuel source, the irrigation sector of fresh water use is increasing. As new coal, nuclear and other thermoelectric power generation facilities come online they will consume more fresh water overall. And as the human population continues to grow we will consume more and more fresh water .
Additionally, water in the U.S. is under-priced , which leads to much greater consumption . The U.S. has one of the cheapest prices for fresh water in the world, with the average household paying $1.10/m2 of water. Contrast our water prices to those in France, where homeowners pay over $3.00/m2 for fresh water. Our low price of fresh water has contributed to our highest-in-the-world water consumption. The U.S. uses about 1.5 times as much water as Europe, and nearly 8 times that of Africa.
Looking towards the future, there are three key economic, ecological and geopolitical policy measures that can be implemented. (1) Include costs of water when considering energy uses. (2) Improve the efficiency of water use and reuse. (3) Focus on water conservation. While future technologies will help unlock more water supply, it will come at a much higher cost.
-Gleick, P. The World’s Water. N.p.: Island Press, 2000. Print.
-Investments, Fidelity. The World’s Water – Fidelity Investments: Thinking Big . YouTube. N.p., 27 Feb. 2012. Web. 2 Mar. 2012. <http://www.youtube.com/user/
-Mielke, Erik, Laura Anadon, and Venkatesh Narayanamurti. Water Consumption of Energy Resource Extraction, Processing, and Conversion. Cambridge: President and Fellows of Harvard College, 2010. Belfer Center for Science and International Affairs. Web. 2 Mar. 2012. <http://belfercenter.ksg.harvard.edu/files/ETIP-DP-2010-15-final-4.pdf>.
-Parry, Wynne. “Algae: Biofuel of the Future?” LiveScience. LiveScience, June 2010. Web. 3 Mar. 2012. <http://www.livescience.com/13718-oil-algae-biofuels-water-renewable-energy.html>.
- Postel, S.L., G.C. Daily and P.R. Ehrlich. 1996. Human appropriation of renewable fresh water. Science 271:785
-Jones, Tom. “Pricing water.” OECD Observer Mar. 2003: n. pag. OECD Observer. Web. 7 Mar. 2012. <http://www.oecdobserver.org/news/fullstory.php/aid/939/Pricing_water.html>.
- Vitousek, P M, P R Ehrlich, and P A Matson. “Human appropriation of the products of photosynthesis.” BioScience 36 (1986): 368-373. Print.