Mar 10, 2008 (From the CalCars-News archive)
As plug-in cars finally gain recognition as the "cleaner/cheaper/domestic" solution requiring no new technology or infrastructure, journalists aiming for controversy are looking everywhere for critics and skeptics. On February 26 we saw USA Today embellish an already-deficient article with a completely misleading headline, "Plug-in cars could actually increase air pollution" http://www.calcars.org/calcars-news/918.html .
Now we learn electricity is fatally flawed because power plants use substantial amounts of water for cooling (then return almost all of it to its sources). The original story's lamentable headline, "Thirsty electric cars threaten water resources," quickly evolved into Popular Mechanics' over-the-top "Plug-in Cars Could Drain U.S. Water Supply, Researcher Says" http://www.popularmechanics.com/science/earth/4253590.html .
We wish we could respond broadly and rapidly enough so that these misrepresentations don't achieve a broad life, but as we see in electoral campaigns and online memes, "going negative" is often effective. (In the past we've heard urban myths including: solar photovoltaics require more energy to manufacture than they generate during their lifetime; nickel-metal and lithium batteries are also energy intensive to manufacture and are poison when recycled, and a Hummer is cleaner than Prius.)
Here's the original report, followed by our brief rapid response, then comments from Carey King, author of the cited study, who thinks PHEVs make sense and calls the headline "unnecessarily alarmist." Finally, we add in an unrelated hit on PHEVs by venture capitalist Vinod Khosla.
http://environment.newscientist.com/article/dn13418-thirsty-electric-cars-threaten-water-resources.html 'Thirsty' electric cars threaten water resources 06 March 2008
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.
"I wouldn't sound the alarm that this is going to ruin the day," says 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."
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.
Paul Denholm of the US Department of Energy's National Renewable Energy Laboratory in Golden, Colorado agrees that water scarcity will become an increasing problem for utilities, but he doesn't think electric vehicle usage will have much of an impact.
"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".
Denholm co-authored a 2007 study based on data from Colorado showing that if 30% of gasoline-powered vehicles were replaced with plug-in hybrid electric vehicles getting 39% of their energy from the grid, the region would experience only a 3% increase in total electricity demand.
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."
Journal Reference: ASAP Environmental Science and Technology (DOI: 10.1021/es0716195)
FELIX KRAMER'S RESPONSE AT NEW SCIENTIST:
Grid Impacts Of Plug-in Cars 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.
CAREY KING'S RESPONSE AT NEW SCIENTIST:
By Carey King Sat Mar 08 04:16:09 GMT 2008 Felix, Thanks for your comments. Personally, I love the idea of electric cars and PHEVs. I'm a member of AustinEV, the local chapter of the Electric Auto Association. I like PHEVs/EVs for the same reasons you mention. Please look forward to our future work that does look at the water impacts for other fuels like oil shale, tar sands, biofuels, etc. This PHEV work was the beginning of an overall assessment. See my blog (http://rationalenergy.blogspot.com/) for some comments related to this and another past article about our PHEV-water paper. You'll see that I don't believe the water intensity is a hindrance for PHEV/EVs. Keep up the good work!
SCIENTIST CAREY KING'S RESPONSE ON HIS OWN BLOG
Postdoctoral Research Fellow, Bureau of Economic Geology, University of Texas at Austin
http://rationalenergy.blogspot.com/2008/03/another-article-this-time-in-new.html Friday, March 7, 2008 Another article about my PHEV/EV and water usage - unneccesarily alarmist
Another article, this time in New Scientist, has been written about my paper on "water of the plugged-in automotive economy". See a recent post on water used while driving on electric miles for my basic take on how to interpret the analysis. [he distinguishes between water withdrawal and water consumption at http://rationalenergy.blogspot.com/2008/02/water-for-transportation-publication-on.html ]
Phil McKenna, the journalist and writer of the article, chose the title " 'Thirsty' electric cars threaten water resources". This is an unfortunately alarmist title. The article prompted some to blog on the New Scientist page that I was against plug-in hybrid electric vehicles (PHEV) or electric vehicles (EV). This is certainly not true. Some suggested I must be paid or work for some petroleum or natural gas company. This is also certainly not true.
I gave Phil information to present the scope and scale of electric driving upon the electricity grid and water resources, but he didn't mention this.
- 1 million PHEV40s (PHEVs that have a 40 mile range) would drive about 7.3 billion miles per year. This is about 0.3% of miles driven by light duty vehicles.
- The resulting water consumption is 1.7 billion gallons, or ONLY 0.13% of water consumption already associated with power generation.
- The resulting water withdrawal is 76 billion gallons, or ONLY 0.11% of water withdrawal already associated with power generation.
I, and my coauthor, chose to independently look at link between energy and water. This work is a first foray into this area, and we have also analyzed other fuels (biofuels, hydrogen, coal to liquids, etc.) that is in the review process for publishing.
So ... NO ALARM. We have time to plan for 10s of millions of PHEVs, let's get them on the road!
KHOSLA DISMISSES PHEVs Meanwhile, Silicon Valley venture capitalist Vinod Khosla, while backing some battery startups, is still betting mostly on ethanol, now from corn, in the future from cellulose. He sees no alternative to powering all of the miles driven by clean liquid fuels, while PHEV advocates want to fuel most or all of the local miles electrically, with an evolving mix of fuels providing the range extension. At the Washington International Renewable Energy Conference conference in Washington last week, CNET http://www.news.com/8301-11128_3-9885575-54.html reports him saying,
Expensive products like plug-in hybrid cars, which may be the darlings of environmentalists, simply won't drive large-scale change, he said. "Plug-in hybrids are irrelevant because they are too expensive. Unless you can make 500 million or 800 million of those, it won't matter," he said. His contention that plug-in hybrids are irrelevant, or "toys," a case he made late last year at a conference, brought fierce criticism from environmentalists.