This guest post is the sixth from Wendy Pabich in a series on the global water crisis. Wendy is the author of Taking on Water: How One Water Expert Challenged Her Inner Hypocrite, Reduced Her Water Footprint (Without Sacrificing a Toasty Shower), and Found Nirvana. She holds a Ph.D. in environmental engineering from the Parsons Water Resources Laboratory at MIT.
With a carbon footprint comes a water footprint. Every time you turn on the light switch, not only are you consuming energy and adding to your carbon footprint, you are also increasing your water footprint. Electricity production requires tremendous volumes of water to power steam-generated turbines and to cool equipment. In fact, more than half the total water withdrawals in the U.S. each year feed our electrical grid. In some regions of the country, these withdrawals for electricity production are contributing to water stress.
The volume of water required depends upon the energy source. A recent study by The River Network, Burning Our Rivers: The Water Footprint of Electricity, estimates that it requires between zero and 231 gallons of water per megawatt-hour of electricity produced using wind and PV solar technology, and between 14,811 and 440,000 gallons per megawatt-hour for hydropower, coal and nuclear. On average, the water footprint of the electricity we use is about 42 gallons per kilowatt-hour (or 42,000 gallons per megawatt-hour), and the monthly energy use of the average household translates to nearly 40,000 gallons of water—five times the direct water use of that same household.
Conserving energy—turning off lights, insulating your hot water heater, and using Energy Star appliances—then, conserves water. This week’s Taking on Water Challenge is to switch out just one incandescent bulb for an energy-efficient LED or compact fluorescent one, saving about 42 gallons of water per week, or almost 2,200 gallons per year.
For more information see:Burning Our Rivers: The Water Footprint of Electricity
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