Alex Wilson, of BuildingGreen, has written two blogs posts recently that I think will be of interest to Zero Resource readers…I’ve posted snippets, but I recommend reading the entire original posts.
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Averaged statewide , roughly 5% of California’s electricity is used for moving and treating water and wastewater. (The oft-quoted figure of 19% includes water heating and other things we do with water in homes, businesses, and farms.) But these figures vary widely in different parts of the state. A 2005 report from the California Energy Commission found supply and conveyance of water to range in intensity from 0 to 16,000 kilowatt-hours per million gallons (kWh/MG), while filtration and treatment varied from 100 to 1,500 kWh/MG, distribution varied from 700 to 1,200 kWh/MG, and wastewater collection and treatment varied from 1,100 to 5,000 kWh/MG. Not surprisingly, average totals are far higher in southern California (12,700 kWh/MG) than in northern California (3,950 kWh/MG).
By weighting thermoelectric and hydroelectric power generation sources, the NREL report calculated an average water-intensity of electricity in the U.S. to be 2.0 gal/kWh. So if you use 500 kWh per month, that’s requiring, on average, 1,000 gallons of water.
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