Biofuels solar-energy-water-use

Published on October 15th, 2010 | by Zachary Shahan


Water & Energy Facts (Blog Action Day on Water)

October 15th, 2010 by  

This post is part of our participation in Blog Action Day 2010, which is on the topic of Water.

If you didn’t know, we use water to pump crude oil out of the ground, remove pollutants from power plant exhaust, flush residue after fossil fuels are burned, cool power plants, and much more. Our energy resources rely on water, much more than we probably realize. Exactly how much water?

A study from the Virginia Water Resources Research Center found a couple of years ago that:

1. “Fossil-fuel-fired thermoelectric power plants consume more than 500 billion L of fresh water per day,” or about 95 L of water for 1 kilowatt-hour of electricity.

2. Comparing water use efficiency of different fuel sources, natural gas is the most efficient fuel source and biodiesel is the least efficient (this analysis did not include solar or wind energy).

water use according to fuel source

3. When it comes to power generation technologies, hydroelectric, ironically, is the most water efficient, followed by geothermal and solar thermal. Nuclear energy is by far the least efficient, followed by fossil fuel thermoelectric (also very high).

Water Use According to Power Generation Technology

How Do Solar PV and Wind Compare?

Want some water use info on solar PV and wind energy? This is what the California Energy Commission found regarding the water use efficiency of solar PV and wind energy:


Technology gallons/kWh liters/kWh

Wind [1] 0.001 0.004
PV [2] 0.030 0.110


Now, compare that to what the California Energy Commission found regarding water use efficiency of conventional power plants:


Technology gallons/kWh liters/kWh

Nuclear 0.62 2.30
Coal 0.49 1.90
Oil 0.43 1.60
Combined Cycle 0.25 0.95


As the American Wind Energy Association (AWEA) notes, “Wind therefore uses less than 1/600 as much water per unit of electricity produced as does nuclear, and approximately 1/500 as much as coal.” Solar PV isn’t quite as water-efficient as wind energy, but it is also tremendously more efficient than other energy sources.

So, aside from the other environmental benefits of solar and wind energy, water is another big one to take note of. With water resources being used up at completely unsustainable rates, this will become an increasingly important part of the equation and will surely have a stronger and stronger effect on the costs of different energy sources.

Photo Credit: bkusler via flickr

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About the Author

is tryin' to help society help itself (and other species) one letter at a time. He spends most of his time here on CleanTechnica as its director and chief editor. Otherwise, he's probably enthusiastically fulfilling his duties as the director/editor of EV Obsession, Gas2, Solar Love, Planetsave, or Bikocity; or as president of Important Media. Zach is recognized globally as a solar energy, electric car, energy storage, and wind energy expert. If you would like him to speak at a related conference or event, connect with him via social media:, .

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