the math used for the article is based off an erroneous principle. 113 million btu's is stated as what is needed to build a prius. while that is true, it takes 9x that many btu's to produce those 113 million that are used at the plant. say what?

according to the dept of energy, only about 20% of the available energy in oil is used to make mechanical energy, the rest goes out your exhaust pipe.

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another 5% is lost in the drivetrain (or in the case of making electric, in the generator itself), another 3% or so lost in transmission and another 3% or so lost in conversion back from electrical energy to mechanical energy. this is slightly more efficient than coal energy, but only 85% of the world's electric supply comes from fossil fuels, so 9x is relatively safe.

that 113 million BTU's has now grown to a shade over a billion to make it, giving us a total of around 1.5 billion BTU's... this does not take into account that you still have to get it from Japan to anywhere USA where you'll buy it... a group of BTU's you don't have to account for on a used car. thus, a used corolla is about 2.5x GREENER than a new Prius, once the actual math is played out.

in truth, a new prius is little greener than a used f-150, and not as green as a used dodge grand caravan.

You seem to be confused about the origin of the 113 million figure. It has NOTHING to do with drive trains and engine efficiencies or anything else to do with driving the car. It is the estimated energy to produce the raw materials, assemble them, and ship them to their final desination. Things like the shipment from Japan to the US are precisely what IS embodied in the 113 million figure. Any inefficiencies are already included in this number. For example, during the shipment, the energy used to move the car is not what matters...rather, it is how much energy was put into the boat, divided proportionately among its cargo.

Your 9x figure is literally dividing apples by oranges.

wrong.

the 113 million, as stated by the lantern, is the actual number used to build the car at the factory. the 9x is the amount of BTU's used to make those ones that were physsically used... this is the same reason why an electric car is much less efficient than than often implied. you may not be using the BTU's here, but you had to use tehm somewhere to get the energy that you have.

like it or not, even if the energy wasn't used IN the factory to build you car, it was produced, and thus the pollution that goes with it, to make the energy to build your car. thus you are ultimately responsible for it. without your purchase, it would not have been made.

pathtoefficiency:

like it or not, even if the energy wasn't used IN the factory to build you car, it was produced, and thus the pollution that goes with it, to make the energy to build your car. thus you are ultimately responsible for it. without your purchase, it would not have been made.

That would only be true if the car were made to order, which it isn't. It gets made and (presumably) someone buys it - it could be you, it could be someone else. Of course, if enough people buy them the manufacturers make more - but really, it isn't my fault that energy and materials got put into whatever I'm buying, if it was made according to a standardized procedure on an assembly line.

Also, what Sakura said was right: there's no point in bringing the actual operation of the car into an argument about how much energy it took to manufacture. When someone asks you how many BTUs went into building the car, talking about how much energy goes into operating the car is not relevant. And every machine, whether it's a car, a server or your dishwasher, wastes some energy in the course of its normal operation, so that isn't something you can hold against the Prius. In fact, part of the point of a hybrid is that it's designed to use less energy, because when you roll down a hill you get some of that momentum back as power for your car.

What with all the figures and irrelevant information you're throwing around, I can't really tell what you're actually saying anyway. Since you are writing and not talking, you have the time to work out a reasoned argument: there's no excuse for not doing so, especially when you're trying to tell someone else they're wrong.

Wrong again. The 113 million BTU figure comes from a highly sophisticated model called GREET, from Argonne national laboratories.

It does not just include energy "at the factory", but all energy used in shipping, production of raw materials, and any relevant energy transfer inefficiencies. In any case, even if it didn't include all this (which it does), you would still be wrong. Why? Because you are assuming EVERY STEP OF THE PROCESS is run by highly inefficient combustion engines. This is obviously false. Most of the energy is electric or direct thermal (to melt the iron, for example). These have much higher efficiencies than 11%.

Inefficiency HAS ALREADY BEEN ACCOUNTED FOR IN THE MODEL and YOU HAVE VASTLY OVER-ESTIMATED IT ANYWAY.

Sakura's point is well taken. To add to this if the car is made in Japan , then isn't alot of their electricity generated by nuclear power , which is basically non polluting, and alot of steel is made in electric furnaces especially high grade for automobile bodies.

Just counting BTU's doesn't tell the whole picture.A million btu's from coal is far worse for the environment than a million btu's from hydro or nuclear.