I think if we have to debate the small factors that go into something to come up with it we are doing it wrong. We should look at the bigger picture and just stop the really large sources that are beyond doubt of being a big contributor.

        Sigivald said:

It still looks to me like you have to get a MUCH more efficient car to replace your existing one for it to be a net energy win – especially if it might not last the full 160kMi that the provided analyses assume. For a Toyota or a Honda, that’s a safe assumption. Not so much for a GM, sadly.

I wouldn’t say 160kMi is a safe assumption for any car. Sure, the car may last that long mechanically, but it depends on how well the person takes care of it. No matter how well it’s made, it could be dirty, scuffed up, have moldy french fries down in the crevas behind the seat, have sand ground into the carpet badly enough to wear away the fibers and otherwise just be in crappy condition. In that case it might not be worth keeping on the road by the time it gets to 120kMi.

(Believe me, I’ve seen cars ready for the junk heap due to no design issue but due to not getting any care).

Then there’s the issue of accidents. Considering the cost of replacement body panels these days it’s surprising what an insurance company will consider a total.

The AskPablo/Triplepundit numbers seem to suffer the same issue of counting only materials production energy use and using vague estimates of percentages of materials.

But there’s also the energy used by the factory itself, the endless machining and production processes, and countless other costs (hell, the energy used by the workers on their commute!)

(Shipping a RORO full of vehicles from Japan isn’t exactly free, after all. (It’s hard to find good information on RORO fuel economy, but this one is a good starting point.

Tokyo to Portland (a common destination for Toyota unloading) is 4,216NM. At 11.5 knots, that’s 366 hours to cross. That ends up being 80 gallons of fuel per vehicle just in sea transport fuel – 300L. Which is oddly more than half the construction cost of the vehicle.

Proving, again, that we can’t just look at materials cost.)

It still looks to me like you have to get a MUCH more efficient car to replace your existing one for it to be a net energy win – especially if it might not last the full 160kMi that the provided analyses assume. For a Toyota or a Honda, that’s a safe assumption. Not so much for a GM, sadly.

(Snark time: Not surprising, I suppose, for an analysis from a “sustainability engineer” (?) who is an MBA rather than an actual, well, engineer.)

        The Curtains said:

Dr. buzz0,

Would you be able to provide a link to the data you mentioned about organic food and emissions? I would love to read it. I have read some of your archived posts about organic farming, and would like to read more about it.

Cheers mate.

Here are some studies on nitrous oxide emissions from farming and especially organic farming. Bare in mind that organic farming techniques that reject concentrated fertalizer tend to be very tillage-intensive and tend to place a large amount of biological material on the soil surface:

http://www.ingentaconnect.com/content/bsc/sspn/2007/00000053/00000005/art00015
http://soil.scijournals.org/cgi/content/abstract/70/2/570
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TC6-4TDBM65-1&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=937383902&_rerunOrigin=google&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=1b09ce0512c9ba28ee31afd3fabd38fd

http://www.ars.usda.gov/research/publications/publications.htm?seq_no_115=196301

No till and reduced till farming:
http://www.lesspub.com/cgi-bin/site.pl?332&ceNews_newsID=1516

http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6T5T-4BWCBY3-3&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=937392272&_rerunOrigin=google&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=1dbe3ef367ae52a1779b21522a3904c8

Other info:

http://calorielab.com/news/2008/05/05/organic-food-may-not-be-as-great-as-some-say/

http://www.bbc.co.uk/bloom/actions/organic.shtml

http://www.pesticideinformation.eu/2008/06/the-truth-about-organic-farming-in-europe-johnston-vs-melchett/

http://www.wired.com/science/planetearth/magazine/16-06/ff_heresies_03organics

http://www.independent.co.uk/environment/green-living/the-great-organic-myths-why-organic-foods-are-an-indulgence-the-world-cant-afford-818585.html

I will try to find more info on the rates of methane generation from intentional composting versus landfill or burning of biomass (also bare in mind that organic farming produces more biomass waste due to lower yeilds per plant of fruit or other final product) as well as the implications of composting on methane oxidation rates.

It’s amazing how much info is out there claiming that organic farming is better without producing any evidence or looking at a very narrow area. for example, several sites mention nitrous oxide from agriculture and then say organic farming is better without even saying it produces less (it is implied strongly though) or giving a reason why it would.

Would you be able to provide a link to the data you mentioned about organic food and emissions? I would love to read it. I have read some of your archived posts about organic farming, and would like to read more about it.

Cheers mate.

        mdf said:

which has estimates for fuel:manufacture like 75% and 90% for a Prius and Hummer. Still not getting into the “immense” class to my eyes. The author of that web-page comes to a similar conclusion, recommending that old, inefficient, cars be removed from service for “the good of the planet”.

I disagree on that. In fact, I’d think the most “green” option for transport would be to get a very old yet small car that is ready to go to the junk pile and be turned (at best) into scrap steel and revive it to drive it as long as possible, thus preventing the need to manufacture a new car.

The “effeciency” issue is not something that I think is as cut and dry as one might think. Newer cars may have some improvements and of course hybrids have advantages (especially in city driving due to regenerative breaking) but when you get down to it, small light weight cars get the best gas mileage.

One of my friends in high school had about the s**tiest cars you can imagine. I mean it was SO bad that if you were making a comedy movie and wanted a ridiculously crappy car for the movie, this would be a good choice. He got it for free, because in high school and without a job… that’s kinda what you’re limited to. This car was epic it was so bad. It was so bad people took pictures of it and it was a kind of legend. he was the kid with the crappiest car around.

The car: A 1984 Toyotta Corolla (this was in the late 1990’s). It was very badly rusted. The exterior sheet metal on the doors was literally gone (like a gaping hole looking into the inside of the door. NO A/C. Heat barely worked. Radio did not work. The headlight switch didn’t work, so his uncle had wired up a jerry-rigged switch to the headlights that dangled under the steering wheel. It a 75 horsepower push-rod cam motor. I believe it had power steering at one time that no longer functioned.

One of the back doors did not stay closed because the latch was broken. It was wired shut. The car must have had 200,000 VERY ROUGH miles on it in the upstate New York salted roads.

I can’t even find a picture to convey how bad it was. This image: http://removeurcar.com/images/home.jpg Is of a car in better condition than it.

No I am not exagerating.

Now, anyone else would have junked that car long ago. He drove it for more than two years. It ran okay. I helped him put new spark plugs in it and flush out the engine oil. (twice… what came out looked like thick goo).

Anyway, the small engine Corolla from 1984 has a millage rating of something like 46 MPG. I swear it had close to that even at the age. I mean it used less gasoline than almost any car I’ve seen.

Now I submit that if you were desperate to keep that car on the road to the bitter end, you could have gotten another five years out of it. You’d need a couple more rolls of duct tape but it drove and the engine worked reasonably well. Who knows how long it would take before the engine or transmission blows out and can’t be repaired?

And the MPG rivals that of a prius.

Immense?

http://portal.unesco.org/education/en/file_download.php/a01355752c9e869a63cc5651084cfa30Cars+and+energy.pdf

… says that the energy in a car’s construction is about 20,000MJ. Energy content of gasoline is about 40MJ/L, so that 20,000MJ is about 500L of gasoline. That much gas will push a very efficient car about 10,000km … or about 1/20th to 1/30th of its life.

That estimate may be off though, since there is also this:

http://www.triplepundit.com/pages/this-week-david.php

which has estimates for fuel:manufacture like 75% and 90% for a Prius and Hummer. Still not getting into the “immense” class to my eyes. The author of that web-page comes to a similar conclusion, recommending that old, inefficient, cars be removed from service for “the good of the planet”.

I’d really like to see a good comparison of methods that takes into account these factors, but I have yet to find any studies that actually do an objective comparison of the methods.

I’ve seen data that claims organic farming is less greenhouse gas intensive by showing the energy needed to produce conventional fertalizers and then saying organic doesn’t use this energy, but never does the data consider the energy for organic methods. It basically assumes that there is no emissions.

        gman said:

That’s really very true, and it is why these plans to subsidize purchase of ‘new efficient cars’ to get ‘old clunkers off the road’ are really suspect. By suspect, I mean ‘covertly supported by people who stand to gain’ from them.

There are frequent references to organic food being good for reducing global warming or greenhouse gas emissions. These claims usually don’t give much reason. They just say “We need to cut down our carbon footprints and go to less greenhouse gas intensive methods of doing things like reducing energy usage, using green energy sources and eating organic food” Or “One way you can help reduce greenhouse gas emissions is by eating organic.” Or just “Help stop global warming – eat organic.”

They never give the actual reason for this, they just state it. Actually one of the advocates of “organic agriculture as part of a greenhouse gas reduction stratigy” is one of the high ranking agriculture commissioners in the EU. (Oh yeah.. also she happens to own a rather large organic farming operation.. she says that that is not a conflict of interest because it’s actually her husband who runs the organic farming side of things…. right)

I’ve never seen any real evidence that organic agriculture is less intensive when it comes to greenhouse gasses. In fact, I’ve seen some evidence that it is more intensive. One thing that contributes a considerable amount with farming is oxidation of nitrogen compounds in the soil. This is accelerated greatly by tilling. If you leave the soil alone it oxidizes slowly but the big thing that speeds it up is agitating it. Conventional farming doesn’t till nearly as much as organic farming because most of the fertilizers are designed to be water soluble and avaliable in their raw form. Organic farming relies on a lot of composting and soil working. This means it needs more energy for the effort but also more nitrogen oxidation – This is directly associated with high tillage farming methods.

The other thing is that organic farming relies heavily on composting (not that conventional farming doesn’t to some degree), but considerably more so in organic farming. Intentional composting of agwaste and biological materials produces quite a bit of methane. Compared to burning such waste or even putting it in a landfill (where it may actually not decompose for a long time, making it a kind of carbon sync).

Compost piles and rapid composting methods tends to decompose the matter faster than it can be resaturated with oxygen which leads to more anaerobic respiration and thus methane.

        Sigivald said:

Putting off replacing your car is a great way to conserve, however. The energy used to produce a car is immense compared to the mere fuel uses of driving it.

That’s really very true, and it is why these plans to subsidize purchase of ‘new efficient cars’ to get ‘old clunkers off the road’ are really suspect. By suspect, I mean ‘covertly supported by people who stand to gain’ from them.