What really is the greenest car?
December 13, 2009 in Alternative Fuel Vehicles
Did you know that you can save fuel and run your car on water
iambuf asked:
Hybrids definitely have the best gas mileage and, as far as I know, some of the cleanest emissions (for gasoline engines), but I have heard that with a life-cycle analysis the environmental footprint is much higher, mostly due to the battery.
I know riding a bike and taking transit is exponentially ‘greener’ than driving, but IF one had to drive…
What about buying used cars? That is very green from a solid waste side. And if you buy a used car that gets good fuel efficiency, like an old civic, I have to wonder if that is greener than buying a new hybrid…?
My only other thought is buying cleaner burning diesel engines, like some of the new volkswagons, because diesel has historically better fuel efficiency, so if they find a way to control their dirtier emissions (which it seems like VWs did..?) that seems like a good option too.
Any other thoughts?
Thank everyone!
Did you know that you can save fuel and run your car on water
I have a Honda Civic GX. It is the only alternative fuel vehicle that comes directly from the manufacturer to the consumer that is available right now. It uses natural gas for fuel, the same nartural gas delivered to homes to heat them. It puts out less of every emission than the hybrid version of the same car and has been determined to be the cleanest and greenest car that is available to the general public in the United States. Overall it expels about half the emissions of that same hybrid.
You can buy electric vehicles if you want to wait on a list for a long time or accept one that is only legal in your neighborhood side streets, but these are not practical because you can’t just walk in buy one that is fully functional as an only vehicle.
There are a few examples of custom made electric cars that use a solar battery to charge their batteries, that would be the greenest car available if you could actually get one.
Can’t beat these ….
I like the 65 Mustang.
With a life cycle analysis the greenest car would be any used car that is about the be turfed. If you can then fix it up to meet air emission standards you’ll be laughing. The amount of energy needed to product any type of new vehicle easily outweighs the amount of gas or whatever fuel system this vehicle would use with regular driving for many years.
I haven’t found any data on life cycle analysis of car manufacturing from cradle to grave, but i am extremely certain that the amount of energy and pollution caused by this system would outweigh the poor fuel efficiency. You have to take into account everything from the basic mining process, to the energy used to dispose of this vehicle after its useful lifetime.
If you can get further use out of an old car it will be more energy efficient in a cradle to grave life cycle analysis.
(However you may still worry about local environmental damages like oil leaks, and bad emissions.)
The attached source shows a very very basic life cycle analysis on a new car, so obviously any new car you buy you should go with a hybrid, electric, diesel, or possible smart car variation.
The Geo Metro and Honda CSX both got better mileage than any hybrid I know of now. They didn’t have all the extras cars come with standard now. My brother drives horribly, either speeding on the freeway or in stop and go traffic and he gets around 40 mpg in his ford probe. Lithium is a rare element (expensive) and I expect close to 100% of car batteries will be recycled so the footprint isn’t as big as some claim. Corning has made a filter of some type that cleans up diesel emissions pretty well.
A 1982 Dodge Omni gets better gas mileage than a Prius.
The greenest car would be one running on carbon negative fuel. Such a fuel would be synthetic gasoline or diesel synthsized by Fischer Tropsch synthesis of syngas from a biomass gasifier.
Such a gasifier produces the syngas which is carbon monoxide and hydrogen by pyrolysis and can use anything that burns as feedstock, even old tires and dried sewage.
The process converts 51% to 80% of the carbon in the feedstock to fuel while traditional bio fuels like ethanol and biodiesel only converts a fraction of the food part of the plant which in itself is just a fraction of the plant hence converting less than 3% to fuel, even algae to biodiesel only produces up to 50% conversion and the byproducts of the traditional biofuels all release their carbon as CO2 in a few short years.
The byproduct of gasification, charcoal when used as a soil ammendment known as biochar will sequester some of the carbon thereby resulting in a net reduction of atmospheric CO2 for at least thousands of years (we don’t know how long it will remain stable for, all we know is the biochar from the Indians of the Amazon thousands of years ago is still stable and sequestered.
The synthetic fuels could be delivered through existing distribution infrastructure and used in existing vehicles without modification effectively turning all vehicles green. What it doesn’t do is increase the market for new cars and hence profit for auto manufacturers.
So the choice is to stick with existing vehicles but change our gasoline production to biomass to liquid technologies and reduce the carbon in our atmosphere or promote the purchase of brand new vehicles whether they be hybrids, hydrogen, electric, CNG or flexfuel under the guise of being green, allowing the automakers to increase their production and their profits, keeping auto workers employed but all at the expense of the environment since he increased production itself contributes a generous amount of carbon and these technologies are at best carbon neutral.
It’s ironic that the path most people consider green actually increases the CO2 levels significantly and only marginally slow down the annual increase in CO2 while the option that most people see as polluting (keeping existing vehicles but changing to BTL) actually removes CO2 from the atmosphere.
The best solution would be switch to BTL with the existing gas guzzlers, let the gas guzzlers clean up the atmosphere a bit by running on the carbon negative fuels ie.: let the SUV owners pay to clean up their own mess and then phase in the newer cars slowly so as not to make the auto industry dependent on even higher production and sale rates.
See the American Council for an Energy-Efficient Economy’s Green Book. They rate vehicles on both their fuel economy and their emissions. The greenest vehicles available in the US for 2009 are:
Make and ModelSpecifications aEmission Standard
MPG: City MPG: Hwy Green Score
HONDA CIVIC GX1.8L 4, auto [CNG]cTier 2 bin 2 / PZEV243657
TOYOTA PRIUS1.5L 4, auto CVTTier 2 bin 3 / PZEV484553
HONDA CIVIC HYBRID1.3L 4, auto CVTTier 2 bin 2 / PZEV404551
SMART FORTWO CONVERTIBLE / COUPE1.0L 3, manual [P]TIer 2 bin 5 / ULEV II413649
TOYOTA YARIS1.5L 4, manualTier 2 bin 5 / ULEV II293646
NISSAN ALTIMA HYBRID2.5L 4, auto CVTPZEV353346
You can also use the US EPA’s Green Vehicle Guide (no subscription needed) to compare vehicles in each class for the best in fuel economy and emissions.
The VW diesels are still not sold new in states with California emission standards, as they are still too dirty (NOx and PM). But Audi, BMW, Mercedes-Benz, and Volkswagen all have some diesels that qualify as advanced lean-burn technology vehicles for a US tax credit.
There’s a lot of myth, urban legend, and misinformation out there on hybrid vehicle batteries and vehicle production, thanks to a flawed marketing paper by CNW and a poorly researched student newspaper opinion article that keep getting quoted…
Anyhow, I suggest reading:
Hummer versus Prius: “Dust to Dust” Report Misleads the Media and Public with Bad Science:
Prius Versus Hummer: A Nickel for Your Thoughts:
“I read an article stating the Prius has a worse impact on the environment than a Hummer because of the enormous pollution created in making the car’s batteries. True?” :
Giving Directions: No, the Hummer Actually Isn’t More Energy Efficient Than A Prius, Let’s Put This “Debate” To Rest:
Usually the mythic “article” from The Mail on the nickel in the hybrid cars’ NiMH batteries is quoted from a now retracted article. The retraction that clears up this bit of misinformation is at:
(They were using data from the early 1970′s about the INCO-Sudbury nickel mine, which was more than 20 years before the first hybrids needed NiMH batteries, and the plant has greatly cleaned themselves up and reforested the area since then. If you were to add up the amount of nickel in the million+ hybrids sold since 1997, that total is still less than 1% of the world’s annual nickel production (far more nickel is used for stainless steel, for example).)
(Even the journalism student author of the much-quoted student newspaper article has posted a followup here: and the newspaper had to issue a clarification: )
What you heard is incorrect – the more electric a car is (from hybrid to plug-in hybrid to fully electric), the smaller its lifetime carbon footprint becomes.
Only 5-10% of a car’s lifetime energy use comes during production and disposal, while 80-90% comes during operation. See pages 4-5 in the link below.
So what that tells you is the car with the most energy efficiency is the car with the lowest overall carbon footprint. Electric motors are far more efficient than internal combustion engines, so that’s hybrids and electric cars.
As for the battery, they’re fully recyclable, so they have a very small carbon footprint.
As for new ‘clean diesels’, they might be a fairly environmentally friendly option. Better than gas cars, but probably not as good as hybrids. You have to bear in mind that the new technology which makes them ‘clean’ also makes them more expensive and reduces their fuel efficiency.
A bike made from Bamboo
The (German?) “Twike” should be a serious contender for greenest. It’s a 2 place _pedal_car_ which is electrically assisted to go 55 ish. It is not too pretty and, at $35000 in the US, it isn’t exactly cheap. See link below.
I find think it would be cool to get a workout going to work! A little exercise would do me some good.