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Advertising They may not be gas-guzzlers, but electric cars have a raging thirst for water. A comparison of the volume of coolant water used in the thermoelectric power plants that provide most of our electricity and that used in extracting and refining petroleum suggests that electric vehicles require significantly more water per mile than those powered by gasoline. The findings could bode ill for drought stricken areas in the event of a large scale switch to plug-in vehicles.
Carey King from the University of Texas, Austin, US, noting that no mass-market electric vehicle is currently available. "But looking into the future, this is something we should take into account." Dry cooling King and colleagues found that cars, light trucks, and SUVs running off the electric grid consume three times more water and withdraw 17 times more water per mile than their equivalent gasoline-powered vehicles. For electricity generation, "consumed" water is the amount of water lost to evaporation whereas withdrawn water is the amount of surface water a power plant uses and later returns to its source, typically a nearby lake or river. King says one way to mitigate water-use impacts of electric vehicles is by switching to dry cooling using forced air instead of water to cool steam in power plants. The technology has been around for years but remains more expensive than water cooling; something King says could change as available surface water becomes more scarce. Another alternative is to move away from thermoelectric energy sources such as coal, nuclear, and natural gas, to renewable sources. If we use only wind or solar energy, water use would be essentially zero, King says. "As electricity demand increases in general, water requirements especially in drought prone areas will become increasingly important," Denholm says. But "the overall impacts of plug-in vehicles are modest in the larger scheme of things".
The current infrastructure could easily handle this increase because most vehicles would be charged overnight during off peak hours. "It's going to be several decades before we see enough plug-in vehicles to have any kind of impact," Denholm says. "It's hard to say if the grid we have now will be the same grid we have when we begin to see a large number of plug-ins."
VIEW THREAD >> Grid Impacts Of Plug-in Cars By Felix Kramer Thu Mar 06 18:20:29 GMT 2008 Let's focus on the main impact: greenhouse gas emissions, which are about half as high for an electric mile as a gasoline mile (even on the national, half-coal, power grid). When we get to secondary impacts, if we compare gasoline to electricity, the latter is also cheaper (under $1/mile equivalent) and domestic (in the US, we don't use imported oil to power our plants. If we look ahead to "dirtier" gasoline that could provide additional supplies, analysts who look at the amount of water and other resources used in processing/extracting oil from shale and tar sands are horrified. And I've seen estimates that each gallon of ethanol derived from corn uses 500-1500 gallons of water. Looking ahead, electricity can come from increasingly clean, renewable sources, while gasoline is stuck or goes backward.
VIEW THREAD >> Grid Impacts Of Plug-in Cars By Felix Kramer Thu Mar 06 18:21:04 GMT 2008 Let's focus on the main impact: greenhouse gas emissions, which are about half as high for an electric mile as a gasoline mile (even on the national, half-coal, power grid). When we get to secondary impacts, if we compare gasoline to electricity, the latter is also cheaper (under $1/mile equivalent) and domestic (in the US, we don't use imported oil to power our plants. If we look ahead to "dirtier" gasoline that could provide additional supplies, analysts who look at the amount of water and other resources used in processing/extracting oil from shale and tar sands are horrified. And I've seen estimates that each gallon of ethanol derived from corn uses 500-1500 gallons of water. Looking ahead, electricity can come from increasingly clean, renewable sources, while gasoline is stuck or goes backward.
VIEW THREAD >> King Overstates Her Case By Dmm Thu Mar 06 18:32:08 GMT 2008 King is mistaken when she says, If we use only wind or solar energy, water use would be essentially zero. First, several types of solar energy are thermoelectric -- they use the sun's heat energy to boil water that runs a turbine. They have the exact same usage problems with cooling water as power plants running off of coal, oil, nuclear, gas, etc. Second, photoelectric semiconductor-based solar power needs large amounts of water for manufacture of the panels.
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