Prius truly green?

yes ,,

green or not ,, i hear those ideas and calculations from people sometimes.....

It may sound silly ,but if we are going to se if a product polutes more because (or create more or less in the end) of the way its made compared what it pollutes in use or simmilar,, Well then there are even factors that i guess seldom gets used in int he calculations..

just a few toughts....

what about the transport of the factory workers , busses cars, small or big cars.?
transport of the materials?
handling of waste products?
Does the company of the product has a green profile,, meaning will some of the money they make on the product be used to make new/improved green products.?
what about the country that the company pays taxes to, does it have a green profile ? meaning will the money You buy the product with , that goes to the company , that some goes to the worker salary and taxes, ad some goes into taxes the company pays, will theese money make/stimulate more or less pollution ?

and many more


therse so many factors that will actually decide the result,

just a tought

Andreas

 

<div class='quotetop'>QUOTE(Jonnycat26 @ Feb 28 2007, 05:35 PM) [snapback]398099[/snapback]</div>

Whoo Hoo :lol: Two points!

Yes, start with what you want to believe, throw in the numbers, mix vigorously, and it's quite easy to prove what you want. It's all about the initial thesis you set out to prove.

 

<div class='quotetop'>QUOTE(Tech_Guy @ Feb 28 2007, 01:21 PM) [snapback]397914[/snapback]</div>

I'm not anti-bike, I used to bike-commute to my job, I'm a member of the Wash Area Bicyclists' Assn, but with regard to your statement, I have to say, maybe yes, maybe no.

The hitch is that food is the fuel for bicycling, and it takes roughly 10 fossil fuel calories to produce one edible calorie in the typical American diet. If I ate the typical American diet, at my weight, I'd get roughly the equivalent of 66 mpg when bicyling, assuming that all the calories expended while cycling were replaced by additional food consumption. If my family of four bicycles together, we get substantially worse gas (fossil fuel) mileage then if we drove the Prius. Most of those fossil fuel calories are, by the way, used to produce meat (particularly grain-fed beef), so a vegan on a bike is much more fossil-fuel efficient than a carnivore on a bike.

A good brief overview can be found here:

http://bicycleuniverse.info/transpo/beef.html

 

<div class='quotetop'>QUOTE(chogan @ Feb 28 2007, 08:25 PM) [snapback]398157[/snapback]</div>

I'm not sure this argument holds true for anyone not at their ideal weight. If you've previously consumed many more calories than you need, it's not valid to count that against the cycling efficiency.

Less tactfully, most of us are already too fat.

 

Hi All,

Here is some quantitive comments about ocean transport. As the trip takes such a long time compared to accelleration time (and power) the main fuel usage is to overcome hydrodynamic drag. The hydrodynamic drag directly related to the wetted surface area. And how low the ship sits in the water (and how much the wetted surface area is) is directly related to the weight of the cargo.

To do a true hybrid effect evaluation, I will compare a V6 Camry to a Hybrid Camry. Both have similar accelleration, passenger volume and load capacity. The Felicty Ace car carrier ship can handle 6400 cars See:

http://www.mol.co.jp/carcarrier.shtml

Put 6400 V6 Camry's ( 3516 pounds) versus 6400 Hybrid Camry's (3680) lbs, and the ship sits lower in the water by 525 tons. But the ship itself weighs 60,118 tons . See:

http://www.e-vrp.com/Vessel_Details.asp?Ve...mp;PlanNum=3631

So the ship is going to sit lower in the water by .9 % (525/60118) due to the hybrid system. So, we can expect the wetted surface area to increase by less than that, as with a loaded ship, an additional .9 % will be causing the water to come up higher on the slab sides of the ship. So, that means the ship burns no more than .9 % more fuel to come to the USA with Hybrids versus equivalent standard cars. As we pay about 700 dollars for shipping of our Prius (which also includes in-the-USA costs, not just the car-carrier ship costs), I will estimate that .9% cost $6.3 per car, or $40,320 dollars more in car-carrier ship fuel. This assumes the shipping company is doing the service as a break-even not-for proffit operation, and 100 % of the costs of transportation are fuel related. This is a big overestimate in other words.

But the fleet of V6 Camrys will burn about 150 % as much fuel as the fleet of hybrid Camrys (26.5 mpg versus 39 mpg EPA combined). How many miles does the fleet of 6400 hybrids require to recoup the extra shipping cost of $40,320 ? At 50000 miles, the fleet of 6400 V6 Camrys will have burned up 12,075,472 gallons of fuel. The Hybrids Camrys will burn up 8,205,128 gallons. For a difference of 3,870,744 gallons per 50000 miles, which is almost $10 million dollars at present gas prices. Scaling, and assuming $2.50 a gallon, break even on the transportation cost occurs at 208.4 miles driving by each car.

Which is a rediculously low value to be arguing about. Especially, with the bias of uncertainty towards maximizing the estimate of car-carrier ship fuel consumption I made. It seems Mr Spinella is living up to his name! The Spin(ella) factor on this one is 150 K (average car life) / 208 miles, or 721.

New Definition: Spin(ella) factor - the factor by which something is wrong that a Marketing Consultant says is right.

 

So, did anyone actually read the answer to the OP's question?

http://www.toyota.co.jp/en/k_forum/tenji/pdf/pgr_e.pdf

 

<div class='quotetop'>QUOTE(Jonnycat26 @ Feb 28 2007, 06:35 PM) [snapback]398099[/snapback]</div>

Were you being Ironic too?

Seems to me your 'numbers' have as much or more potential to 'lie' as his.

The correct question is - What percentage of drivers died in Car Accidents compared to the percentage of cyclists who died.

By your math if three out of a million drivers die while both of the only two cyclists die, that proves cars are more dangerous than bike riding because more people died driving.

My money is on a higher Death/Injury RATE for cyclists, which is the proper evaluation of risk.

 

<div class='quotetop'>QUOTE(Tempus @ Mar 1 2007, 12:34 AM) [snapback]398268[/snapback]</div>

Not really, and we really don't know the true nubers, do we?

College areas do have high numbers of bicycle riders, higher than normal, which is going to skew the data.

And I'd also like to know if the people killed/injured were wearing helmets. But that's just me. And since I don't think we're going to get numbers, the point is moot.

 

<div class='quotetop'>QUOTE(Tempus @ Feb 28 2007, 11:34 PM) [snapback]398268[/snapback]</div>

This is a topic of interest to me, as the closest I've ever come to dying on the highway was on my bicycle.

I didn't think there would be any reasonable data on this, because it's tough to estimate the underlying population. But here's a nice study out of John's Hopkins. Almost all bicyclist deaths are due to cars, and a third of bicyclist decedents were legally drunk at the time.

http://www.smf.org/articles/injury.html

They conclude the death rate *per trip or per passenger mile* is much higher on a bicycle than in a car. But that may or may not be the correct set of denominators from which to form your judgement.

Obviously, there is some uncertaintly there. The absolute number of deaths per 100,000 total population is much higher for cars (about 12/100,000) than biclcles (about 0.3/100,000). So bicycle deaths are rare. The entire credibility of the statistic rests on counting who is and is not a cyclist, what is and is not a trip. I did not read the study to figure out how they went about that.

Be that as it may, there's yet another view of this: in the grand scheme of things, cyclists are so much healthier than average, their all-causes mortality is lower than non-cyclists. Not sure what to make of that, except that, at least for the older population, you can reasonably make the argument that the health benefits of cycling outweigh the accident risks. This is the link to the abstract of a study at the National Library of Medicine.

http://www.ncbi.nlm.nih.gov/entrez/query.f...p;dopt=Abstract

 

<div class='quotetop'>QUOTE(hyo silver @ Feb 28 2007, 07:43 PM) [snapback]398175[/snapback]</div>

You are correct, my analysis was a steady-state analysis and assumes that you replace the calories burned -- that your weight is stable.

But I think that's not an unreasonable way to look at this.

If bicycling causes you to lose weight, then during the period of weight loss I'd say you could reasonably call the calories derived from stored fat to be free energy. Cycling merely liberates the existing free fuel. Every excess pound that permanently disappeared would represent free fuel.

But if your weight remains stable over the longer term, then you've eaten food calories to replace the cycling calories, and my original argument applies. Even if you drop some weight, then put it back on, you've replaced the bicycling calories with food calories.

To be as clear as possible, I'd say my argument does not apply only when you use up fat and never replace it. So there can be a short-term "free ride" as you change from an overweight to less overweight state. But there's no on-going free ride in the long run.

That's my take on the physics of it. A calorie is a calorie. The only free ride is from the current stock of excess fat, which you get via the permanent reduction of the existing excess stored fat.

But from the standpoint of behavior, I could see other views with modestly different conclusions. For example, the data clearly show that people get fatter as they get older, on average, as their matabolism slows. If you view that as somehow free fat -- that that fat is going to happen anyway, and somehow the calories that go into making that age-related fat don't count in this calculation -- then now you have a permanent annual addition to the pool of excess fat you can draw from to power the bicycle. So, maybe, bicycling to avoid age-related weight gain would be another free ride. But that weight gain is typically on the order of a pound or two per year, which isn't much of a free ride. A pound of body weight is worth about 2000 calories -- so you'd get maybe 50 - 100 free miles per year. After that, you've maintained your weight, and everything else costs you more food calories. So, I could stretch this to say, under that interpretation, maybe your first 100 miles a year or so are free. After that, we're back to my argument.

Well, now I'm on the slippery slope. If you buy that argument, then how about the "my weight naturally stays way above the healthy range" argument? So, if you bike to avoid what would be a "natural" weight gain of (say) 10 lbs, that is going to occur no matter what if you stop bicycling, then ... nope, I draw the line there. If bicycling causes your total caloric intake to increase, then those calories are the cost of bicyling. If bicycling causes you to maintain a weight that is 10 lbs lower than otherwise, but increases your caloric intake, then the 10 lbs is free (as above), but the increased intake at the lower weight still counts as the cost of bicyling. Somebody has to grow and supply that food, and the fossil fuel required to do that is what I'm focusing on.

Not to say that the health benefits of cycling are not great, just to say that it wouldn't necessarily solve our fossil fuel issues if we junked cars and bicycled the same number of miles. If bikes were the main form of transport, it would increase food demand, and that would require fossil fuel. And that a trip in an efficient car with a load of passengers (four people in a Prius, say) might reasonably consume less fossil fuel than the same trip taken by bicycle, accounting for the fossil fuel required to replace the cyclists' calories.

 

The statement that it takes 10 calories of fossil fuels to produce one calorie of food is somewhat misleading if you assume that's what it takes to travel on a bike and the general population started to do this. Two thirds of Americans are overweight/obese. Cycling would not only reduce the girth, but health costs and energy costs involved in it. There would be less auto use - less repairs.

I'd suggest trimmer people would be slightly more inclined to buy large vehicles. When people gain weight, they buy larger sizes for clothes....and probably vehicles.

While the original question "How much CO2 Does it Take to Transport a Prius Across the Ocean?" seemed worded to imply it polluted more than a conventional car in transit, there is a valid point. Being carbon neutral goes far beyond the car you drive.

 

[snip...]

 

<div class='quotetop'>QUOTE(Delta Flyer @ Mar 1 2007, 06:57 AM) [snapback]398374[/snapback]</div>

Seems like someone already addressed this issue:

http://www.kenkifer.com/bikepages/advocacy/bike_co2.htm

A pound of fat will get you about 100 miles.

 

<div class='quotetop'>QUOTE(Squint @ Mar 1 2007, 09:44 AM) [snapback]398417[/snapback]</div>

I agree that a pound of pure fat will get you about 100 miles. A pound of body weight lost through exercise is about half pure fat, half other stuff (fluids, connective tissue, etc.) and is typically reckoned at about 2000 calories per pound.

The posted link was grossly incorrect. His numbers just flat out ignore the fossil fuel required to produce food. You can either say that completely misses the point, or that assumes away the key issue. Either way it's not right.

Look at the bottom line of his table. It says that the calories in 20 lbs of rice provide enough energy for 1000 miles of bicycling, at 35kcal per mile. That's a correct calculation. But that's all he counts -- the food calories.

I note that if I take that website's bottom line number (food calories required to travel 1000 miles), and multtiply by 10 (my estimate of the fossil fuel that was required to produce those calories, at the US average diet mix), then compare to the mileage of the Prius, I get 78 mpg for the bicyclist. This is essentially no different from the 66 mpg that I calculated for myself as a bicyclist.

So, this guy gets a nice low number, but only by ignoring the main point.

The point is that that producing and processing the average American diet takes lots of fossil fuel. Exactly how much is debatable, but all the reasonable answers say that it's quite a bit.

You can turn to any number of academic studies to find estimates of this. Those estimates will vary. But here, the first paragraph of this study pretty much gets to the heart of the matter:
http://www.organic-center.org/reportfiles/ENERGY_SSR.pdf


"Each year, the food system utilizes about 19 percent
of the total fossil energy burned in the United States
(Pimentel et al., 2006) (Figure 1). Of this 19 percent, about
7 percent is expended for agricultural production, 7 percent
for processing and packaging, and 5 percent for distribution
and food preparation by consumers (Pimentel et al., 2006).
If forestry production and utilization are included, the total
for the food, fiber, and forestry sectors of the economy
rises another 5 percent, to 24 percent of national fossil
energy use. This amount of energy (24 percent) is similar
to that consumed by automobiles each year in America
(USCB, 2004-2005)."

If that Cornell U professor is right that the US food chain consumes 19% of US fossil fuel (and my study of the national income and product accounts suggests he's at least in the ballpark), then you actually come out with a net 14.5 fossil fuel calories per edible calorie in the US diet, when you factor in agriculture, processing, transport, cooking, and waste. You can do that calculation yourself if you wish, starting from total US fossil fuel consumption of 86 trillion BTU per year (US DOE, http://www.eia.doe.gov/emeu/aer/pdf/pages/sec1_3.pdf), convert to Kcalories (1 btu = 0.252 Kcal), take 19% of that, and compare to total actual US food consumption based on an average 2600 Kcal per person per day (USDA data, figure 1, lower line at this URL: http://www.ers.usda.gov/publications/FoodR...frvol25i3a.pdf), for 300 million people for, 365 days per year. The arithmetic gives you 14.5 fossil fuel kcalories per edible kcalorie.

Anyway, if you start with the micro-level studies of the inputs to agriculture, or you just do the long division based on the aggregates (which are based on the national income and product accounts), you get something like 10 fossil fuel calories (or maybe 14.5) per edible calorie consumed. The aggregate calculation isn't exactly right because you'd need to net out exports and net in imports of food. We're a net exporter so it's probably a modest overestimate. But it's in the ballpark. Other sources will show lower numbers. But nobody suggests that it's zero or even small. Ten seems to be a good ballpark number.

The guy they cited, Pimental, has done detailed estimates for meat production and some other foods. But meat is where most of the energy use is. For example, here's a summary of Pimemtal's work on the fossil fuel inputs to agriculture, done at Cornell University. Look for the paragraph on "fossil fuel to food"

http://www.news.cornell.edu/releases/Aug97...estock.hrs.html

Anyway, the wesite you cited simply ignores the issue -- does not account for the fossil fuel inputs to the American diet.


So, I think that's the basis for going forward. If my assumption about 10 fossil fuel calories per edible calorie is correct, and if you replace the calories used in cycling with food calories, then you get 66 mpg (my estimate for me) or 78 mpg (my estimate based on that website) bicycling. If you eat the average American diet.

Then the rest of it boils down to: do you have to replace the calories used for transport with food calories. Well, I bike commuted 32 miles round-trip for a few years, and in that case, you must certainly do. So if bikes are used that way, then yes, you have to replace the calories.

Beyond that, I'll stick to my original analysis. Energy doesn't come from nowhere. If you are actually losing weight, then sure, the calories from buring that fat are free. But if you are at a stable weight (stable thin or stable fat), then additional calories spent bicycling must come from additional food intake.

I'm not disagreeing with health benefits, I'm not disagreeing with the notion that while a person loses weight through bicycling, you don't have to count the calories. I'm not disagreeing that more physical activity of all sorts would be good for the average, overweight American. But at the typical American diet, I continue to disagree with the notion that converting a substantial fraction of US transport to bicycling would impose little or no fossil fuel burden. The energy to move the bike comes from food, and the average American diet calorie requires substantial fossil fuel inputs.

 

<div class='quotetop'>QUOTE(Dan. @ Feb 28 2007, 05:13 PM) [snapback]398083[/snapback]</div>

Nice to know somebody else delved into the details as well. It is interesting that car companies still exist, since by the Spinella numbers, all car companies would have gone bankrupt long ago (or their suppliers, and/or the governments who are apparently subsidizing all this). But something that jumped out at me, is that he apparently counts the salaries of the workers, but also counts transportation costs getting the workers to work, etc. Seems to me a whole lot of double-charging is going on here, but he doesn't get into any details of how that is accounted for. In fact, the only thing I could think of that wasn't being accounted for was road repairs (which is strongly affected by the weight of the vehicle). But he knows the efficiency loss of a Prius ten years out to the tenth of a percent, so you gotta believe this. I just wonder why, for an "objective" report like this for the entire car market, why he always highlights the hybrids only in the charts.

Did you see most large SUV's, like the Yukon, Tahoe or Excursion get over 260,000 miles average lifetime? Puts both the Aveo and Prius to shame, we should take some lessons from them.

However, you must have missed the note in my previous post, where the 2006 model year results are out. He doesn't have the big report on them, just the summarizing spreadsheet. New numbers:
Aveo: $.74/mile (was $.77)
Prius: $2.87/mile (was $3.18)
Tahoe: $3.76/mile (was $2.94)
Excursion: $4.04/mile (was $3.30)

So to re-iterate my earlier post, the Prius is no longer more expensive per mile than a large SUV. No details were given as to how these numbers changed, like average rise in large SUVs of 25%, the biggest change of any category. And for some reason, this new study was not publicized nearly as much.

 

<div class='quotetop'>QUOTE(nerfer @ Mar 1 2007, 01:57 PM) [snapback]398640[/snapback]</div>

Well he plainly admitted (think I quoted it actually) that he put all the HSD drivetrain R&D costs on the back of the Prius, and only divided the total HSD R&D by the number of Prius sold to-date. Since the later study probably had a much larger number of Prius sold to-date, the R&D figure probably dropped a lot.

He may have changed his fueling costs as well. This was one of my favorite pieces of logic. I think he only counted the cost of fuel and didn't include tax or margin. If I recall the figure was like $0.40 per gallon, but then he tacked on the cost of the filling station infrastructure or something like that. It basically made fuel costs non-linear so that it wasn't tied to fuel efficiency.

Ohh well... don't know why he would have increased the SUV costs though. Who knows what this guy was thinking. My guess is $$$$

 

<div class='quotetop'>QUOTE(chogan @ Mar 1 2007, 11:47 AM) [snapback]398553[/snapback]</div>

Interesting stuff. For the number you have of 35kcal/mile, is that above the baseline of kcal/mile for driving a car? (which is considerable less, both by activity level and the fact you commute probably 2x or 3x faster, but it's still not zero).

Also, to be complete you should consider health costs. I heard from an HR person that 50% of health care costs come from 'preventable' conditions: smoking, obesity, lack of exercise (diabetes, emphysema, heart conditions, etc.) Whereas a bike rider is likely to be quite healthy and prescription-free up until the day he/she is smacked by a truck. Optimally, this smackage occurs shortly before drawing social security benefits, for maximum societal benefit.

And how does this compare to costs of eating out? I'd wager a sizable percentage of each portion is wasted, both in production and non-consumption, that wouldn't occur at home. This kind of thing would likely put effects of bike riding into the noise margins. I would think you could easily compensate for the added food cost of biking by eating out less. Being a vegetarian would make it that much easier.

Call me selfish, but I want to have many healthy years ahead of me. Since driving a car to a gym to workout is the worst scenario, and also wastes much time, I still intend to bike to work when I can.

But you are absolutely correct, gas used in commuting in just a small part of our total energy needs. I heard that if all cars doubled their gas mileage, we would reduce our CO2 emissions by 10%. Which seemed way too low to me, until I found that 40% of all energy consumed in the U.S. is in the form of petroleum, and 2/3rds of that is for gasoline and diesel, resulting in about a quarter of all energy is used for transport, halve that and you get about 12% or 13% savings. Not insignificant, but not a cure-all for our energy use and CO2 emissions. Food, housing, other factors are also big players.

 

<div class='quotetop'>QUOTE(nerfer @ Mar 1 2007, 01:28 PM) [snapback]398668[/snapback]</div>

Fitday has driving a car at 135 kcal/hr and riding in car, truck or bus at 68 kcal/hr.

I found another site that discusses this issue:

http://bicycleuniverse.info/transpo/beef.html

In the notes it mentions that Pimentel has had to revise his numbers downwards.

 

<div class='quotetop'>QUOTE(nerfer @ Mar 1 2007, 03:28 PM) [snapback]398668[/snapback]</div>

I'm agreeing with all the above. The 35 kcal/mile, I'm pretty sure that's the additional energy above baseline. At least, that's what I used when I calculated my MPG and the numbers match up OK. Clearly varies with weight and speed of the cyclist.

The point about bicyclists' health is well taken. In my earlier post on the hazards of bicycling, I noted that while it is more hazardous to bike than drive, all-causes mortality rates are lower for bicyclists. That suggests (but does not prove) that the health benefits outweigh the risks. (Does not prove it because it could be self-selection -- could be health people chose to bike, rather than bicycling makes you healthy.)

Do the additional calories just get lost in the noise? For a casual cyclist, sure, that's plausible. Doesn't mean they aren't there, just means you can't put your finger on them. But if you go at it hard enough, it's like any other endurance sport -- your calorie needs go way up. So if bikes became the principal means of transport, that would affect food demand. As for food wastage, that's included in the estimate. You want a real eye-opener, look at the USDA data I cited above. They have two lines, which are essentially calories of food prepared and calories of food actually consumed. I have no idea how they get their data, but the "consumed" calories is about two-thirds of the total calories. So it looks like a third of potentially edible food just goes to waste. Again, no idea what that consists of.

This certainly wouldn't and didn't stop me from bicycling. Just made me feel kind of cheated, somehow, when I figured this out. I used to believe my bike commute was good for me and good for the environment. But my alternative was to take the Metro, which is densely-used rail transport and therefore has a very low emission per passenger mile. In retrospect now, on net, I really do believe that I actually slightly increased net CO2 emissions by bicycling to work instead of taking the Metro, given my diet at the time.

My next-door neighbor owns a bike shop (Bikes at Vienna, a great place if you are looking for an unusual recumbent or folding bike, btw.) His phrase is: "It's a sick society where people drive to the gym." I wanted to put that on a bumper sticker, but that didn't seem right somehow.

I'm such a nut on the food thing because a) a most carbon calculators ignore it, including US statistics on household average C02 generation, b) a family of four can eat three-quarters of a ton of food / 1 million kcalories a year, so just the raw mass of the food itself appears large compared to other household inputs, c) when I did the carbon calculation for my family, the implicit fossil fuel value of the food was (and remains) the single largest line item on the household carbon budget (of heat, electric, cars, and food), and d) when you get into the numbers, it's becomes pretty clear how needlessly environmentally destructive a meat-heavy diet is. (If a diet is one-quarter animal products, at the US average animal product mix, those animal products account for three-quarters of the fossil fuel used to grow the food.) That convinced me to switch to local grass-fed beef, based on the particular conditions here in VA (temperate well-watered climate with existing year-round pasturage.) Not clear that same decision would be as large a winner in colder or more arid climates. Not clear that merely displacing grain-fed beef is an adequate step, either. A vegan on a bike is the most efficient form of personal transportation known, but I'm not quite ready for that.