PHEVs could potentially drain our water supplies - or not
It takes water to drive your car. Not in the sense that your car is powered by water, but in the sense that our power plants in the U.S. often use steam for either cooling or to power turbines. In fact, at 195 billion gallons of water consumed per day, power generation is second only to irrigation when it comes to using our water supplies. According to a study published by the American Chemical Society, PHEV's require 17 times the water supply that gas-powered cars need. That's a huge difference, and it's a constant figure unless you are getting your power from renewable sources, like wind, geothermal or solar. Of course, that "study" needs some explanation, which CalCars provides in spades. Basically, since many of those gallons of water aren't "used up" and other forms of energy generation use water as well, the anti-EV sentiment is out of porportion. Carey King, the researcher who worked on the study called the Popular Mechanics' headline "unnecessarily alarmist" and said that "You'll see that I don't believe the water intensity is a hindrance for PHEV/EVs."
Still, issues like water use remind us that there are many considerations to make when purchasing your next vehicle. Off-peak charging of your PHEV is one way to be sure that you are not putting to great a burden on water supplies; paying extra for renewable power is another.
[Source: The American Chemical Society via Popular Mechanics, CalCars]
Reader Comments (Page 1 of 1)
harlanx6 10:25AM (3/11/2008)
We have volcanic eruptions, asteroid collisions, economic breakdown, drug resistant diseases, etc to worry about (if we are compelled to worry). This new worry, just doesn't pass the BS test!
What are they selling? A book or something?
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Eric Lemieux 11:21AM (3/11/2008)
You seem to have forgotten Hydro in your renewable sources list (we have mostly that in Québec) ... oh wait, that requires water and EV are about to drain it all out, nevermind. ;)
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Dan 11:26AM (3/11/2008)
Yeah... except you don't need to use potable water to steam off the heating coils in power plants. So really... you wouldn't be drinking that water anyways.
Even after that fact, the steam returns to the atmosphere where it falls back as clean, clear drinking water (provided the area is free of smog and pollution).
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rgseidl 11:42AM (3/11/2008)
Coal- and gas-fired power plants are typically located near rivers. If there were a large fleet of EVs and these were trickle-charged at night, the existing power plants and grid could deliver the additional electricity.
The coolant water required to support the increased night-time load currently passes the power stations by. Some would be lost to evaporation, but most would be returned to the river, albeit at an elevated temperature. There will be an impact on downstream hydrology and ecology, but that must be weighed against the reduced dependence on oil that EV fleets deliver.
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jpm100 11:44AM (3/11/2008)
Kind of ironic for this site, but nuclear power plants hold the answer. Not in the way you might think.
Those hourglass shaped towers people often associate with nuclear powerplants have little to do with the nuclear reaction and mostly to do cooling. Some versions recondense the superheated water for reuse.
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BoomBoom 11:49AM (3/11/2008)
The electrical grid in most places is having trouble keeping up with our current growth patterns, not to mention the increase in electrical demand that will result from autos needed electricity. I've seen no reports looking at the additional load which would be caused by plug-in EVs. Rgseidl is right that if most cars charged at night, they would use the system when it was otherwise under utilized, but I'm not sure that EVs won't need more energy than that.
I'm all for plug-in EVs, but I think that there are alot of associated issues with a dramatic increase in electrical demand that no one seems to talk about. (Like the issue raised by the article.)
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Tim 12:29PM (3/11/2008)
BoomBoom.
Grids by necessity are designed for Peak power requirements which happen in mid summer afternoons between 2:00 and 4:00 when full office buildings need air conditioning.
EVs will be charged at night and there is currently PLENTY of excess capacity to charge MILLIONS of them without adding any new plants. It will take many years before we have enough EVs on the road to require any investment in new plants. During that time renewable electricity technology and cost will improve so distributed (home made) electricity will take much of the load off the grid extending (perhaps indefinitely) the need for new central power plants.
EVs that charge at night will also help to balance or "load level" the grid which would maximize its potential and help grid operators better amortize capital investment. This increase in efficiency would LOWER the cost of electricity.
All of these factors (and more) must be taken into account in any reputable analysis. Media sound bites need NOT apply.
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KarenRei 12:35PM (3/11/2008)
jpm100: Actually, nuclear power plants return *more* hot water to rivers than fossil plants per kWh.
Anyways, this article is way overblown. Power plants typically operate at near peak capacity during the day, which means that the maximum hot water they discharge must *already be within the tolerances allowed for their discharge point*. Increased off-peak charging simply means that the water discharge doesn't cycle between warm and cool; it doesn't get any higher of a peak temperature, and hence stays out of the "danger zone".
"I've seen no reports looking at the additional load which would be caused by plug-in EVs."
Then you haven't been looking. Here, let me help you out:
http://www.pnl.gov/energy/eed/etd/pdfs/phev_feasibility_analysis_combined.pdf
The short of it: There's already enough electric infrastructure in the US for 84% of cars, trucks, and SUVs to be switched over to being PHEVs.
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Peekoyle 8:11AM (3/12/2008)
It really is amazing the 'FEAR' mongering I've seen recently regarding EV's.
Whether or not these 'fear' topics are valid seems to me rather irrelevant as we all know the transition to EV's is chronically SLOW.
Heck, it hasn't even really started yet.
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David Wright 5:04PM (3/11/2008)
The headline is sensationalist nonsense. In the past couple of weeks a few of these articles have appeared, attempting to scare people away from electric vehicles. If it is part of a campaign it is too clumsy and too late; there are now too many carmakers in too many countries already committed to pressing ahead with battery electric vehicles. Renault, Mitsubishi, Subaru, Nissan. And today the german firm BMW announced that too will most likely be producing an all-electric car for the US market by 2012.
The race is on. It's going to happen. Those attempting to stop it by dreaming up scary scenarios are wasting their time.
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Mark 6:11PM (3/11/2008)
Sounds like an Exxon-sponsored study to me..
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Mike Miller 10:00AM (3/12/2008)
The fear mongering of every topic has gotten to the point of paralysis in this country. all someone needs to do is get the MSM to hype dis-information and the idea looses the public support. all you have to say it we will loose jobs or prices will increase and the topic is dead. There should be a law against unfounded information/claims simply to discourage innovation.
At least EVs or hybrids can re-capture some of their energy through regenerative braking. there is no opportunity for this with straight fossil fuels.
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Mike Miller 8:14PM (3/12/2008)
Funny how no one mentions that we will use up our water any way if we continue to pursue new power plants due to our increased consumption and lack of efficienct use of the energy we are already producing.
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Julius 11:52AM (3/12/2008)
@ KarenRei,
Add vans, and the estimate drops to 74%.
The biggest assumption in the paper you posted is that the charging will primarily be done at night, during off-peak hours. The other assumption is a 33-mile-per-day average (or roughly 12,000 miles a year). However, that average is a "if we drove 33 miles every day"-type average, and obviously any given day may require more distance driven. Now, given the range of current electrics, some additional charging may be needed during the day to allow additional travel.
They account for this by saying that "Because this study assumes that each vehicle drives 33 miles per day, there is an implicit assumption that the electric energy not used to charge those that drive less is shifted to others that drive more than 33 miles per day.", and though "... this figure is strictly valid for personally owned vehicles, we assign it to all vehicles, including commercial vehicles. This simplification may underestimate the actual daily driving of the commercial vehicles in the LDV fleet."
Which means, the whole program is based on a wild guess. Now mind you, America as a whole has consistently increased its aggregate-miles-traveled, so that implication of under-estimation becomes larger.
And yes, PHEV's can run on gasoline during the day, sparing the drivers from charging until nighttime - but how does that make it different re: gasoline usage from a non-PHEV?
In all, the fact that Michigan is attempting a real-world trial is a good thing.
Like the E85 boondoggle, we don't want to create a legislative mandate without solid data backing it up (and BTW, that paper was really an estimate paper).
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Bill 7:46PM (3/12/2008)
PHEVs will also be charging at non-peak hours during the daytime.
Drive your PHEV to work, plug it in, and it will be mostly recharged by the time you want to go out to lunch (before peak demand)
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jpm100 5:11PM (3/13/2008)
KarenRei:
Some design do that. Others do not. They recapture the heated water and dissapate the heat to the atmosphere.
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