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).
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).
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:
WATER CONSUMPTION–WIND AND SOLAR
| 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:
WATER CONSUMPTION–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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