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"One must wonder whether it might have made more sense to direct this considerable engineering expertise to a mainstream sedan or crossover that could actually achieve 40 m.p.g. or so". (http://www.nytimes.com/2008/04/27/automobiles/autoreviews/27AUTO.html?ref=automobiles)

http://www.cleanmpg.com/photos/data/501/2008_Chevrolet_Tahoe_2-Mode_Hybrid.jpgBob Knoll - New York Times - April 27, 2008

IT would take a magician of considerable skill to turn a large, thirsty S.U.V. into a gas-sipping hybrid, but General Motors has tried to pull just such a big green bunny out of its hat. For 2008, the company’s engineers have installed an innovative hybrid system in a couple of the company’s larger sport utilities, the Chevrolet Tahoe and GMC Yukon, and plan to add the system to other models, including the Cadillac Escalade and full-size pickups, in the coming months.

The technology itself, which began with a clean sheet of paper, is impressive. It is called a two-mode hybrid system because it offers two types of operation, one intended for city driving and one for the highway. Based on the hybrid-drive technology in big G.M. buses, the two-mode was jointly developed by G.M., BMW and the formerly co-joined DaimlerChrysler. All four companies (Daimler and Chrysler have separated) will be using two-mode technology in future vehicles.

G.M. was first to market with the Tahoe and Yukon hybrids, which do manage to be greener without much degradation of their heavy-duty characteristics. They can haul a big boat or trailer and accommodate, in theory, up to nine passengers. And while the hybrid S.U.V.’s get better overall mileage than their conventional gasoline-only siblings — in the high teens in my experience, compared with perhaps 14 — the difference may be less than potential buyers expect.

Ultimately, real-world fuel economy may be less than what was promised either by the company or by the federal ratings on the window sticker. A prospective purchaser will need to consider whether the mileage gains are enough to offset the hybrids’ substantially higher prices.

More fundamentally, shoppers may want to reflect on whether they really need large trucklike vehicles like these instead of car-based crossovers that are inherently more efficient — like G.M.’s own Buick Enclave, GMC Acadia and Saturn Outlook.

G.M. explains its approach — to start offering the system in some of its largest passenger vehicles — by noting that mileage gains in such thirsty models can save the most gallons of fuel (and the most dollars at the pump). In contrast, the gains from a hybrid powertrain are relatively smaller in a relatively small, efficient car like a Honda Civic...http://www.nytimes.com/2008/04/27/automobiles/autoreviews/27AUTO.html?ref=automobiles

Meh. I don't care much about savings when compared to a comparable sized vehicle. What interests me is overall reduction in fuel use. :p

They can haul a big boat or trailer and accommodate, in theory, up to nine passengers

can't they just have these things for rent? and have them outlawed for general purposes unless a pass can be produced? The ratio is 9 to 1 for those things carrying just the driver instead of all the THEORETICAL passengers.

"G.M. explains its approach — to start offering the system in some of its largest passenger vehicles — by noting that mileage gains in such thirsty models can save the most gallons of fuel (and the most dollars at the pump). In contrast, the gains from a hybrid powertrain are relatively smaller in a relatively small, efficient car like a Honda Civic..."

Let's compare 1 quarter of Yukon/Tahoe Hybrid to 1 quarter of Civic Hybrid:


Yukon/Tahoe 4WD 14/19 = 16 MPG Combined
Yukon/Tahoe Hybrid 4Wd = 20/20 = 20 MPG Combined (Q1CY2008 Sales = 655)

Civic Auto = 25/36 = 29 MPG Combined
Civic Hybrid = 40/45 = 42 MPG Combined (Q1CY2008 Sales = 6,520)

Assume that the Yukon/Tahoe Hybrid *REPLACED* 1 for 1 a Yukon/Tahoe.
Assume that the Civic Hybrid *REPLACED* 1 for 1 a Civic.

Each Yukon/Tahoe Hybrid saves 187.5 gallons every 15,000 miles.
Each Civic Hybrid saves 160 gallons every 15,000 miles.

Times 655 Yukon/Tahoe Hybrids, save 122,812.5 gallons.
Times 6,520 Civic Hybrids, saves 1,043,842 gallons.

The entire 1000 vehicle GM-Allison Hybrid bus fleet (http://www.gm.com/explore/fuel_economy/news/2008/hybrids/bus_to_vegas_010908.jsp) saves 1.4 Million gallons per year (30-40 thousand miles driven per year.)

Yeah, GM, you've got the green thang all figured out.

-mr. bill

Gee, I would love a hybrid minivan, not SUV. Hope Toyota or Honda can do wonders to their minivans! Or maybe Chrysler too!

GM is directing its energy to that which they feel will give them (and their buds, the oil industry), the greatest profit.

Of course, in calculating what is most profitable for them, they do not have a very good track record.

All Klutz comes up with is record loss!! Looser.

GM is directing its energy to that which they feel will give them (and their buds, the oil industry), the greatest profit.




BINGO!

Don't forget their friends in Agri-Business, Archer Daniels Midland, et al.

What I like about the Prius is that it was drawn up on a clean sheet of paper (computer monitor, actually) with fuel economy in mind. It was not a compromise. Every decision was made with fuel economy in mind.

The Tahoe is the anti-mpg vehicle, so making it into a hybrid is a waste of time and effort.

Harry

BINGO!

Don't forget their friends in Agri-Business, Archer Daniels Midland, et al.

What I like about the Prius is that it was drawn up on a clean sheet of paper (computer monitor, actually) with fuel economy in mind. It was not a compromise. Every decision was made with fuel economy in mind.

The Tahoe is the anti-mpg vehicle, so making it into a hybrid is a waste of time and effort.

Harry

I just love GM's new TV ad on how all their vehicles run on E85. You know the, "This is how much gas is in gasoline. This is how much gas is in homegrown E85. All GM Vehicles are Flex-Fuel. Toyota doesn't have any." There are a couple of problems with this scenario which I will list for you:

1) Try and find an E85 station. How may are there? A few hundred at best. Their in the Mid-West.

2) E85 contains ethanol derived from 1/3 of the US corn crop. The US provides about 40% of the world's corn supply. Figure 1/3 of 40% yields 10% of world food crop to make ethanol and they plan to increase that share of corn for ethanol even higher.

3) Toyota's Prius and even the Yaris don't need no steekin' ethanol because they run more efficiently and use less gasoline than a Tahoe or any other GM FSP on ethanol fuel.

2) E85 contains ethanol derived from 1/3 of the US corn crop. The US provides about 40% of the world's corn supply. Figure 1/3 of 40% yields 10% of world food crop to make ethanol and they plan to increase that share of corn for ethanol even higher.



I don't know where you got your figures, but the actual amount of U.S. corn used for fuel alcohol in 2007 was a little over 20%, not 1/3. Exports account for less than 20% of the total crop. Most is used for domestic feedstock; putting beef, pork and chicken on our tables. A main byproduct of ethanol production, gluten, is used as a feedstock as well, tempering the affect on ethanol on food prices.

I don't know where you got your figures, but the actual amount of U.S. corn used for fuel alcohol in 2007 was a little over 20%, not 1/3. Exports account for less than 20% of the total crop. Most is used for domestic feedstock; putting beef, pork and chicken on our tables. A main byproduct of ethanol production, gluten, is used as a feedstock as well, tempering the affect on ethanol on food prices.

Possibly, but 1/5 is a significant amount, with or without any byproducts. That means that 80% has to meet a growing need/demand. Something has to give, and unfortunately, price did (http://www.msnbc.msn.com/id/12754620/). You can't take 20% of anything out of supply and not have it increase price unless there's a subsequent drop in demand. Unfortunately, it's very hard to drop demand on corn since it affects so much of the food supply (corn products, other grains, meat as you alluded to, and so on).

I also didn't notice where you got your figures. Care to cite your sources (same goes for Radio_tec)?

Possibly, but 1/5 is a significant amount, with or without any byproducts. That means that 80% has to meet a growing need/demand. Something has to give, and unfortunately, price did (http://www.msnbc.msn.com/id/12754620/). You can't take 20% of anything out of supply and not have it increase price unless there's a subsequent drop in demand. Unfortunately, it's very hard to drop demand on corn since it affects so much of the food supply (corn products, other grains, meat as you alluded to, and so on).

I also didn't notice where you got your figures. Care to cite your sources (same goes for Radio_tec)?

I got them from the USDA:

http://www.ers.usda.gov/data/feedgrains/StandardReports/YBtable4.htm

I agree that demand for ethanol has a contribution to increased grain prices...just correcting the figures. I believe the affect is overstated in many cases in the media and repeated ad nauseum. There are many causes for the increase in world grain prices, increased biofuel demand is just one part of it.

I don't see how you can dismiss the use of co-products...depending on the amount of gluten meal, gluten feed, corn germ, sweeteners (dextrose and HFCS), and corn oil produced, a large portion of the 'wasted' corn is offset. The total affect of corn-based ethanol on American grocery store prices is VERY overstated.

http://www.cleanmpg.com/forums/showthread.php?t=10174

The affect on 'developing' nations is higher, of course, due to their reliance on less processed foods and free American surplus grain that no longer exists. It is an unfortunate situation for them (that is only going to worsen with decreasing oil supplies).

I realize corn-based ethanol is not a long-term solution, as it is not the most efficient use of grain (however feeding it to animals is not that efficient either). More efficient processes using other inputs must be developed and I believe a strong market for ethanol is leading to research and investment in those technologies as we speak.

I believe the transition away from oil is going to be a long, hard trip and we're going to need lots of options.

I got them from the USDA:

http://www.ers.usda.gov/data/feedgrains/StandardReports/YBtable4.htm

I agree that demand for ethanol has a contribution to increased grain prices...just correcting the figures. I believe the affect is overstated in many cases in the media and repeated ad nauseum. There are many causes for the increase in world grain prices, increased biofuel demand is just one part of it.

I don't see how you can dismiss the use of co-products...depending on the amount of gluten meal, gluten feed, corn germ, sweeteners (dextrose and HFCS), and corn oil produced, a large portion of the 'wasted' corn is offset. The total affect of corn-based ethanol on American grocery store prices is VERY overstated.

http://www.cleanmpg.com/forums/showthread.php?t=10174

The affect on 'developing' nations is higher, of course, due to their reliance on less processed foods and free American surplus grain that no longer exists. It is an unfortunate situation for them (that is only going to worsen with decreasing oil supplies).

I realize corn-based ethanol is not a long-term solution, it is not the most efficient use of grain (however feeding it to animals is not that efficient either). More efficient processes using other inputs must be developed and I believe a strong market for ethanol is leading to research and investment in those technologies as we speak.

I believe the transition away from oil is going to be a long, hard trip and we're going to need lots of options.

Chief 302,

My figures were incorrect based on your USDA spreadsheet. The data discounted my 30% figure for ethanol from corn and 40% for exports. In fact the chart shows that the amount of corn exported is 20% and the amount or corn used for ethanol is lower than 30% as well. However the chart lumps food, alcohol and industrial uses of corn into the same column. Could you explain how you got the 20% figure for ethanol?

Chief 302,

My figures were incorrect based on your USDA spreadsheet. The data discounted my 30% figure for ethanol from corn and 40% for exports. In fact the chart shows that the amount of corn exported is 20% and the amount or corn used for ethanol is lower than 30% as well. However the chart lumps food, alcohol and industrial uses of corn into the same column. Could you explain how you got the 20% figure for ethanol?

Sorry, I got those from a separate table...

http://www.ers.usda.gov/Data/feedgrains/StandardReports/YBtable31.htm

In millions of bushels:

3100 fuel alcohol / 13,110 total disapearance = 23%

I need to find some hard numbers for exactly how much co-products are produced for a given amount of ethanol...