April 28, 2006 10:00 AM PDT

Plug in your hybrid, pollute less?

Do cars that run on electricity pollute less than those that run on gas?

Generally, yes, but the answer depends on where you live, say experts. It also depends on the type of electric-powered hybrid you drive.

Rising gasoline prices, combined with fears about global warming, have prompted sales of hybrid cars, which run on a combination of gas and electricity.

The current oil situation has also begun to create interest in so-called plug-in hybrids. These cars are similar to conventional hybrids but rely more on electricity and get charged through a wall socket. Right now, only a handful of plug-in hybrids exist, but some companies plan to offer conversion kits later this year.

Utilities, meanwhile, often generate electricity both in the U.S. and developing nations by burning coal. Thus, plug-in hybrids can contribute greenhouse gases to the atmosphere even though, as with standard hybrids, the emissions from the tailpipe are minimal.

Widespread adoption of plug-ins, or even conventional hybrids, will likely take quite some time. Consumers keep cars for several years, so the turnover in the market is slow. Car companies remain notoriously conservative. New cars must also thread the testing and safety procedures of various governmental agencies.

Still, it's worth paying attention to the implications for the environment of the new technologies hitting the streets.

As in real estate, location is key. In California, coal produces only about 18 percent of the electricity. A plug-in hybrid will thus produce less than half of the carbon dioxide of a regular car, according to Andrew Frank, a professor of mechanical engineering at the University of California at Davis.

A conventional hybrid like the Toyota Prius--which generates electricity from the battery and heat coming off of the brakes--doesn't get power from the grid. Thus, these high-mileage cars pollute less than regular cars but pollute more than those rare plug-ins.

Joe Romm, a former official with the Department of Energy turned author and clean-energy advocate, certainly sees it that way. In 12,000 miles of driving, Romm says, a gas-powered car will roughly produce 12,000 pounds of carbon dioxide while a Prius might generate 6,000 pounds. A plug-in on average might emit 3,900 pounds. (Other pollutants include sulfur dioxide and nitrogen oxide, products of the internal combustion engine.)

But in places where coal accounts for 80 percent or more of the electricity, the situation changes. There, a gas-powered car and a plug-in create about an equal amount of pollution, making the conventional hybrid the least polluting.

"A worst case does exist. Pennsylvania and Ohio are (mostly) coal. There, the greenhouse gases of a PHEV (plug-in hybrid electric vehicle) to a car are even," said Felix Kramer, founder of the California Cars Initiative, or CalCars. "But you're still getting the benefit of reducing reliance on imported fuel."

Modernization can also tip the balance toward electricity. New coal-burning plants emit lower levels of pollution, for reasons including more efficient equipment in general and technology for capturing of the emissions.

"Power plants are getting significantly cleaner. The reduction on CO2 is pretty significant," said Bob Graham, a project manager for electronic transportation at the Electric Power Research Institute.

To get a better handle on the issue, EPRI is conducting a study of how much pollution a hypothetical plug-in hybrid car would produce in Cleveland in 2015 and 2030. At the moment, 55 percent of the electricity in the city comes from coal while the rest comes from nuclear power and other sources. ERPI hopes to have data later this year. The study will look at carbon dioxide emissions, but also mercury and nitrogen compounds.

Similarly, an increase in solar power capacity could reduce the overall emission of pollutants because more electricity would come from a clean source. Some companies are also looking, further out, at ways to capture carbon dioxide generated at plants in sealed underground caves. Erecting new power plants and solar facilities, however, takes time and money.

Hydrogen, which may become an energy source even further out in the future, has its own greenhouse gas issues too. Most hydrogen today gets produced by mixing methane and water at high temperatures. The process produces 9.3 kilograms of carbon dioxide for every kilogram of hydrogen, according to Gerald Rothwell, a professor of economics at Stanford University. (The carbon dioxide can be captured at the plant, but most commercial producers of hydrogen at the moment let it loose.)

But even if plug-in hybrids or hydrogen take years, drivers can still reduce fumes today.

"A lot of the current hybrids are extremely clean, especially when it comes to CO2," Graham said.

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More important questions
A more important question: is it actually saving money to plug the car in? In all the many stories I've read on plug in hybrids, I've never seen one that actually has any data on miles per kWH.

Furthermore, this article is misleading on CO2 emissions. The nation's power grids are largely interconnected. This means that California, which locally is only generating 18% of its electricity off of coal, is still importing energy from other parts of the country. More electricity use in California indirectly also means more coal is burnt in Pennsylvania.
Posted by NewWorldDan (15 comments )
Reply Link Flag
yes, you do save money
I have Rav4 EV -- 100% electric, which uses approx 0.3kWH per mile (city + highway driving). Rav4 is shaped like a brick & Prius is more efficient (with more modern technology) so perhaps Prius uses 0.2kWH per mile.

So it depends what you spend on electricity. Prior to installing PV, I paid about 0.05 cents / kWH off-peak (charging at night). That would equate to 200 miles/gallon (at $3.00/gallon)

You're somewhat correct about the inter-connectedness of the grid, but recall that California had brown-outs because insufficient power could be imported from other parts of the country -- the wires across Nevada, I suppose, just aren't big enough.

Either way, there is excess capacity for production during off hours: the more we can smooth out the curve & charge a night, for example, the less marginal impact there is on cost or (for that matter) power-plant pollution.

If everyone plugs in at the same time they turn on their home air conditioner, we're all in trouble!
Posted by pbuckner (5 comments )
Link Flag
Energy Savings
I work in HVAC and A/C system design as a mechanical engineer. It is amazing how much focus politically is put on building "green" or friendly to the environment. Saving energy for example by using new refrigerants in A/C units that claim to be super efficient or low polluting. In reality, nothing is free so-to-speak. While the new refrigerants may be more emission friendly in one area, they require more power total because they are really less efficient in another area. Which means in the end, you pay more for the high-tech unit initially, you pay more when it needs to be fixed or replaced, you use about the same amount of electricity as if you had bought a new unit with current refrigerants, and the powerplants burning coal are still smoking away. Hidden factors are things like how difficult and polluting it is to manufacture these refrigerants vs. just using the easier to make ones. The cost and use of resources like metal and fuel to create a new unit that can handle this new refrigerant, and the pollution that it creates. In the end, it's really all about money, not saving electricity or the environment. Don't let the political minded, power hungry politicians fool you into thinking they are saving the world and therefore deserve your vote.

I am all for keeping the environment clean. I am all for new technology and new fuel alternatives, but not much of what we are doing now is fixing anything. I just went to a seminar put on by ASHRAE (American Society for Heating Refrigeration and A/C Engineers) They had on the panel some guys that were pushing the new Green building stuff and environmentally friendly tech to save us from global warming. They spouted off a bunch of numbers about CO2 levels and said if we did not make our building energy cut down to about 10% of what the best Green building is today with a very short period of time that we have no chance of avoiding Global Warming. I did say down to 10% of current usage, not down 10% below current usage. Then they went on to say that even if we stopped making new buildings all together right now, that we might still not be able to avoid global warming. ASHRAE is the leading creator of current A/C design standards, and I am sad to see they would allow this type of garbage to be promoted in this way. Global warming is a scare tactic to get everyone to follow along with this environmental movement so all these equipment companies can make big bucks and pay off whoever they are connected with under the table. Its all about the money, never forget that. And money is power.

That applies to everything from taxes, to laws, regulations, votes, commercials, and more. If its confusing, ask who is getting paid for it. I see it day in and day out in this business. I am sure many other fields are similar.

Feel free to dig up your own research on this. But look for graphs that show the history of temperature that predates modern man all together. Here is a graph I found, there are many more out there even on sites that support global warming theory.

<a class="jive-link-external" href="http://en.wikipedia.org/wiki/Image:Vostok_420ky_4curves_insolation.jpg" target="_newWindow">http://en.wikipedia.org/wiki/Image:Vostok_420ky_4curves_insolation.jpg</a>

What this basically shows is the current year 0 at the left and as it goes to the right you go back in time. You can see that according to this scientific graph, the earth naturally peaks its temperatures because of CO2 and other emissions naturally every 150,000 years. We were not even around in our modern form that long ago. Anyway, you can see that the global warming we are experiences is natural and happens ever 150,000 years or so. Just an example. Sorry for kinda getting off topic. It did apply somewhat to the idea of are we really saving energy.
Posted by limbofrog (20 comments )
Link Flag
Electricity from Brake Heat? Wow!!!!
Can you tell me where I can buy this entropy machine you're describing? I could put it next to my stove, my tv, and my monitor, make a body suit out of it and generate electricity all day!!! Is that why they made humans into batteries in the Matrix?!!

Maybe you could look up how motors and electromagnetic principals, and how moving through a magnetic field causes electricial potential. e.g. converting the kinetic momentum of the spinning wheels into electricity for what would have been lost as entropic friction heat.

How can your article have any credibility if you don't even understand the basic principals behind the technology?
Posted by NuShrike (13 comments )
Reply Link Flag
well, yes and no
While it's true that regenerative braking doesn't, in fact, convert the
brake heat into electricity in any design I know of, it wouldn't be a
violation of physics if it did so. Any heat differential can be turned
into electricity (look up the "Seebeck effect"). You could certainly
generate electricity from your oven, but you'd generate less
electricity than you put into it.
Posted by samkass (310 comments )
Link Flag
No money saved
Spending $11,000 on a conversion kit just means you now have a $25,000 drive train in your $10,000 car.

HowStuffworks did an article that points out that even Hybrids do not really pay themselves off.

They make the claim that these cars will pay themselves off but they do it assuming 100 mph is a realistic estimate of the gas milage when that is likely not the case.

They also fail to account for the added cost of electricity which some estimate would be equivalent to a little over $1 for a gallon of gas.

The problem with this is that when you pay for a gallon of gas around 2/3 of the cost (the other $2) is taxes.

So electricity is really not much cheaper than gas, it just comes with fewer taxes.

The other problem how much pollution is created by manufacturing these cars with $15,000 worth of batteries? What about the fossil fuels used generate electricity for the grid?

The reality of the matter is that you could do more with less simply by buying a more efficient gas powered car for a fraction of the cost of hybrid+kit.

People make a hybrid car, then to save energy they make it lighter, more aerodynamic, use smoother tires etc.

Those same fuel saving design decisions can also be applied to gas powered cars as well be people are not interested but they want to buy into the hybrid, vegie eating, metrosexual, tree hugging, anti animal testing life style.

Just get a scooter with a frapachino and iPod holder and a bigger back seat so you can ride dudes.

You can still be all San Francisco even without the hybrid, and there is nothing wrong with that.
Posted by Dachi (797 comments )
Reply Link Flag
More efficient standard cars?

Where are these more efficient standard cars I can buy? You miss the pointthat better gas mileage also contributes to national security and that by using domestic coal, imported oil use is avoided. New wind powered generation is gradually lessening our use of coal, so the equation of what is ecologically better becomes a moving target. Not all of us who own hybrids are tree-hugging frappacino drinkers. Until your mythical 100 mpg standard sedan comes out of Detroit, I'll just have to hang my gun rack in the back window of my Prius!
Posted by baldguy61 (63 comments )
Link Flag
Reduce our dependence on imported oil
While a plug in hybrid, may or may not reduce overall carbon
emissions, it will definately reduce our dependence on imported
oil. That alone leads me to think it it is a big win.

For example, would be in Iraq now if we didn't import oil from that
Posted by hinden (1 comment )
Reply Link Flag
BS & Iraq Oil
There is one thing I can't stand, and will go bezerk if I hear one more liberal say the only reason we're in Iraq is for the oil! That one statment tells me and others that they just mimic what the democrats tell them without checking anything for themselves....GROW UP. Just because someone who wants your vote tells you something, DOESN'T MEAN IT'S TRUE! I am pasting where America gets it oil from, and as you can see, CANADA is our #1 supplier. We have over 35 SUPPLIERS, so if all of the middle east was removed, we'd still have plenty of oil-PLUS, we have our OWN! And YES, I am all for using Corn Oil, Sugar, whatever in my car-JUST GET YOUR FACTS STRAIGHT and start checking before you pass on others opinion! Read below:


Home &gt; Petroleum &gt; Publications &gt; Company Level Imports &gt; Crude Oil and Total Petroleum Imports Top 15 Countries

Crude Oil and Total Petroleum Imports Top 15 Countries
July 2006 Import Highlights: Released on September 13, 2006
Preliminary monthly data on the origins of crude oil imports in July 2006 has been released and it shows that three countries have each exported more than 1.25 million barrels per day to the United States. Including those countries, a total of five countries exported over 1.00 million barrels per day of crude oil to the United States (see table below). The top five exporting countries accounted for 66 percent of United States crude oil imports in July while the top ten sources accounted for approximately 86 percent of all U.S. crude oil imports. The top sources of US crude oil imports for July were Canada (1.624 million barrels per day), Mexico (1.561 million barrels per day), Saudi Arabia (1.264 million barrels per day), Venezuela (1.191 million barrels per day), and Nigeria (1.014 million barrels per day). The rest of the top ten sources, in order, were Angola (0.666 million barrels per day), Iraq (0.592 million barrels per day), Algeria (0.413 million barrels per day), United Kingdom (0.229 million barrels per day), and Brazil (0.187 million barrels per day). Total crude oil imports averaged 10.153 million barrels per day in July, which is a decrease of 0.528 million barrels per day from June 2006.

Canada remained the largest exporter of total petroleum products in July, exporting 2.113 million barrels per day to the United States. The second largest exporter of total petroleum products was Mexico once again (1.709 million barrels per day) which was a decrease from last month of 0.146 million barrels per day.

Crude Oil Imports (Top 15 Countries)
(Thousand Barrels per Day)
Country Jul-06 Jun-06 YTD 2006 Jul-05 Jan - July 2005


CANADA 1,624 1,799 1,742 1,624 1,608
MEXICO 1,561 1,734 1,662 1,497 1,558
SAUDI ARABIA 1,264 1,427 1,400 1,499 1,522
VENEZUELA 1,191 1,008 1,161 1,327 1,329
NIGERIA 1,014 996 1,097 1,047 1,041
ANGOLA 666 525 480 219 399
IRAQ 592 617 553 615 558
ALGERIA 413 491 314 325 214
UNITED KINGDOM 229 185 146 259 232
BRAZIL 187 107 121 138 88
ECUADOR 170 288 264 217 278
NORWAY 160 92 98 102 133
KUWAIT 155 201 162 272 198
COLOMBIA 144 211 165 172 147
RUSSIA 134 216 98 324 264

Total Imports of Petroleum (Top 15 Countries)
(Thousand Barrels per Day)
Country Jul-06 Jun-06 YTD 2006 Jul-05 Jan - July 2005


CANADA 2,113 2,258 2,249 2,079 2,121
MEXICO 1,709 1,855 1,784 1,593 1,648
VENEZUELA 1,467 1,306 1,455 1,623 1,590
SAUDI ARABIA 1,313 1,522 1,442 1,689 1,597
NIGERIA 1,073 1,094 1,171 1,156 1,131
ALGERIA 743 740 606 535 467
ANGOLA 695 565 501 219 406
IRAQ 592 617 553 615 558
RUSSIA 425 429 349 587 452
VIRGIN ISLANDS 353 273 305 319 326
UNITED KINGDOM 340 355 294 404 376
BRAZIL 274 151 176 156 127
NORWAY 236 140 199 206 242
NETHERLANDS 196 211 185 197 125
ECUADOR 181 295 271 226 287
Posted by jeaniebean (1 comment )
Link Flag
Great Idea
Plug in hybrids are the obvious next step. I'm always baffled at the illogic of the argument some people make that plug-ins simply "relocate" pollution to another place (power plants.) That's patently absurd.

There is no question that converting gas to electricity is absolutely an efficient and intelligent "exchange" to make. If it were not, the hybrid vehicle itself would not get better mileage than the non-hybrid versions of the same car. The "standard 4-cylinder Ford Escape is rated 22/26 and the hybrid version is rated 36/31. Why is that? The obvious answer is that converting gas to electricity and using the electricity to move the car is dramatically more efficient.

Once you recognize the inescapable reality that hybrid technology works (that is gas conversion to electricity works) then you must see the logic of expanding the use of electricity.
Even if (in the most absurd case) power plants used nothing but gas, it would still make sense to go ahead and have those plants do the conversion because the very existence of hybrids proves that this is a "good trade."

More importantly, we would see a truly radical reduction in oil consumption because such a small percentage of America's electricity is produced from oil. (Refer to National Geographic's March 2006 issue for the details: only 3% of US electricity generation is from oil.)

Even more importantly, the very real possibility of replacing electricity produced from oil/coal/natural gas/nuclear with renewables makes "electric cars" profoundly appealing.

The plug-in hybrid is the best, more immediately useable, option we have to make incredible progress towards reducing our dependence on foreign oil.

Personally, I really couldn't care less if the batteries end up needing to be replaced several times during the live of the vehicle. The value of the metals in the batteries alone guarantees they WILL be turned in for recycling.

Any arguments that the "total cost" of either hybrid or plug-in hybrid ownership are really short-sided and simply a reflection that we don't yet properly penalize "gas guzzler" ownership.

As an American I think anyone who wants to drive a Hummer with a load of cement in the back should be allowed to waste all the money they want, but I also think they should pay heavily to offset BOTH the "environmental" and "national security" damage such a car does.

Rather than congress issuing a $100 "gas credit" to everyone, I think they ought to RAISE the tax on gas, then offer a credit equal to the full amount of ALL gas tax but ONLY equal to the average usage. That way people with "normal" car don't pay a dime more, people with efficient cars are strongly rewarded, and people who take pride in their ginormous Ford Excursions can pay for the privilege.
Posted by Yet Another Mark Johnson (66 comments )
Reply Link Flag
Not true
The reason hybrid cars get better milage is not because electricity is more efficient.

When the vehicle stops there is no need for it to be generating any power, so the hybrid cars simply stop the engine.

Cars may need ~100+ HP to not feel "slow" when accelerating but once you hit the speed limit and just need to mantain your speed only ~20 hp is required (so again the gas engine can be shut off).

Ask anyone you collects higher end radio controlled cars, they will tell you that all of the $150+ cars all run on gas.

Electric motors can be pretty small in size, if using electricity instead of gas was so much more efficient why would planes all use very expensive gas guzzling turbine engines? Why not replace battery packs between flights instead?

Yes, and like expensive toy cars toy airplanes also run on gas.

If you want to go spend $35,000 on a plug in prius fine, just as long as you are doing it with your money and don't act like you are doing the rest of us such a f*cking favor you shouldn't even need to pay tax on gas.

The tax break the government gives for these stupid hybrids is more than I paid for my motorcycle that gets better gas milage.

You won't see me asking for a red carpet at the gas station either.
Posted by Dachi (797 comments )
Link Flag
Electric Vehicles
This story is not bad...but there is a lot of hype surronding these 'Green' cars. However, as this story, and many like it, seem to leave out is that although CO2 is a greenhouse gas, and yes it is produced by burning fossil fuels as well as many other ways, it is not the most abundant of greenhouse gases and does not pose the most serious risk to global warming.

The most abundant greenhouse gas is water vapor which in turn creates a possitive feedback loop in the atmosphere...thus eventually leading to more evaporation and thus more water vapor.

So, by pluging in your car instead of burning gasoline you are not really chaning much in the overall picture...the whole picture. In the smaller picture you might be able to breath easier with less smog but you are drawing way more power off the grid from powerplants the produce a heck of a lot of water vapor.

So, I personally would not feel good about driving a so-called 'Green' car because that is really just a lie in many respects since you are transplanting your CO2 emissions with water vapor emissions (on top of CO2 from powerplants as well). So I suppose the gasoline car drive is supposed to feel bad about the gunk coming out his tail pipe while the plug-in electric car driver can feel good because he transplanted his impact upon global warming to the powerstation? Well if your powerstation is wind, solar, hydroelectric or tidal I would not feel too good too soon.

I do not know the cost of these cars when compared to comprible gasoline or diesel cars but if they are more expensive and total life cycle cost comparison would be interesting. Also a total comparison of power from source to point of use comparison would be interesting as well. Because yes gasoline is trucked in from refineries that process oil that is transported very long distances and so on. However, much of the coal, methane or oil used in electricity production is as well. So I would not know the net power output on an electric car from the net total power input to deliver the power to the car versus a similar gasoline vehicle. However, such a detailed investigation would be very interesting and might really answer some of these hard 'Green' questions.

Thank you.
Posted by Ivan Thomson (16 comments )
Reply Link Flag
getting started
it's the power it takes to get a vehicle from a dead stop going that takes the most power, that's why you see the hybrids have mpg figures that are backwards. (more city than hwy), they use the electric motor to get them to 20mph then the gas motor cuts in. it'd be nice to be able to adjust when that cuts in, etc. i understand there are quite a few that have been tinkering with thier hybrids to increase the milage with substantial results. Also, Ford is looking at a hydraulic launch assist technology to work in the same fashion, but it's completely regenerative. should be interesting if it makes it to production, but would help tremendously on large vehicles.
Posted by dbrawders (17 comments )
Reply Link Flag
good points
I don't disagree that global warming is real. But the graph I showed, and many of the "humans cause global warming" groups have similar graph. I guess I am simply pointing out that most people on both sides of the argument don't debate the data shown. What I was pointing out is that if you look back before man was even here, before all of our "dirty" technology, you can see clearly that global warming is a natural occurance on the earth. Much the same way we have seasons, the earth goes through many different types of cycles. Once happens to be about a 150,000 global warming cycle. It is also theorized by some that the magnetic polls, north and south, switch every 100,000 to 150,000 years. Such an event would cause extreme weather changes, might even trigger an ice age, which is also something that appears to happen on the same shedule.

You can also two more things in that graphs data. One, notice the extreme drop in co2 and temp directly after each spike in heat, as opposed to the steady rise of heat that follows over the next 150,000 years. That is global warming causing an ice age each cycle as I said above. Also notice that in the past, at least once, maybe twice, the tempurate and co2 and other pollutants that humans alledgey contribute signifigant amounts to the enviroment, spiked higher than they are currently. Who cause those spikes if we were not even here? Mother nature does this on her own. My point is, your right, global warming is real, but as you can see in the graph, it's gonna come no matter what we do. Even if we are pushing a little faster, the peak is coming no matter what we do. Unless you think we can stop the earth from it's natural cycles, it's gonna come anyways no matter if we all died tomorrow and all human pollution stops. I am not sure stopping tectonic plates shifting and volcanos errupting is a good idea anyways, not mention all but impossible. Talk about screwing with nature.

Again, I am all for new technology and for keeping emisions and polution as low as possible. We just need to live and stop letting scare tactics govern us through fear. We are so regulated right now, everything we sell cost way more than it should. That hurts the poor too. And while the U.S. limits with law production in our country through extreme regulations to apease the enviromental and other special intrests groups, many other nations like china and maybe India don't. We only have 300 million people in the US. China has more than 3 times that. What happens when they get fully into the modern technology age? Then we are all gonna die...
Posted by limbofrog (20 comments )
Reply Link Flag
We are in Iraq for oil. Pretending otherwise is just right-wing bluster. Of course we import oil from Canada. It's right next door. Likewise Europeans import from their neighbors. It's a global, fungible asset and the pricing is interconnected. Iraqui instability equals higher prices for Canadian oil.
Posted by jawshoeaw (13 comments )
Reply Link Flag

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