<Should EROEI be the most important criterion our society uses to decide how it meets its energy needs? The Oil Drum DrumBeat: August 21, 2008>

156 comments on Oil Demand Destruction & Brittle Systems

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enemy of state on August 20, 2008 - 11:09pm Permalink | Subthread | Parent | Comments top

I personally think that gasoline demand can be dropped more than heavy fuel oil demand. Simply because diesel and heavy fuel oils are more "necessary". In other words, most of us could walk to the grocery store, but the grocery store needs deliveries from thousands of miles away.

I see it the other way around. The heavy fuel oil demand is more concentrated on industrial uses. Many of the uses have the potential for fuel switching, or for significant fuel savings, by the substitution of human labor. Take the example of your long distance trucking. At highway speeds roughly 65% of drag is allegedly due to aerodynamic drag. This means the fuel demand, per freight mile is a rapidly increasing function of speed. So the trucker can slow down, substituting his time behind the wheel for lower fuel costs. The automobile driver can do likewise, but his fuel cost savings, measured by his expenditure of time is much lower. Exactly the same thing applies to shipping by water, lower speeds mean higher labor costs, but greatly decreased fuel costs. And this is before technological tweaks. In the case of interstate trucking, trucks could be made more aerodynamic, and a switch from single trailers to double trailers would significantly reduce fuel usage per ton mile. I would think that much of the lowest hanging fruit is in the heavy fuel sector, not the gasoline sector. How many hybrid cars would it take to save as much oil, as a single hybrid garbage truck?

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Wyoming on August 21, 2008 - 6:30am Permalink | Subthread | Parent | Comments top

EOS,

A bit of supporting data for your post.

One of my best friends operates a long haul trucking company. He told me about 6 weeks ago that at 65 average mph his trucks were burning about $12,000 of diesel per month. He decided to limit some to 55 mph and they were burning $10,000 of diesel per month over the same routes. Time to delivery, and other costs, were obviously impacted, but you can see the effect that could be achieved in terms of fuel savings should it be required.

Wyo

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MadMaster on August 21, 2008 - 1:36pm Permalink | Subthread | Parent | Comments top

I thought a lot about reducing truck energy usage. The basic problem is for any real reduction (greater than 10%) of trucking fuel demand, it would take a long time to happen.

The problem is they have already tried a lot of energy reduction. When a 300 gallon tank costs $1200, they think of what they can to reduce that price. Speaking with truck drivers, they don't have options when it comes to reducing fuel use. The best one is driving slower, which will move some of them from 6.5 mpg to 7 mpg. However, it would reduce the amount of freight a trucker could deliver and thus the profit. It is not a very good option for them. Even if it did happen, it would only drop highway truck consumption by ~5% (going from 75 to 55) and less freight would be delivered.

When it comes to replacing trucks with hybrid versions, there are a few problems. Hybrid trucks are really expensive ( 100k or more than a same model diesel ), don't save much fuel (0% highway, 10-20% city) so they are not cost effective. Also, there really aren't many on the market. Full battery electrics are not feasible with todays technology, not an option.

On the flip side, nearly 50% more of us could take a bus/subway or ride a bike to work 3 out of 5 days a week. 10% more of us could telecommute 3 out of 5 days a week. 75% of the SUV's and trucks on the road could be replaced by economy cars (yes I know, this would take a long time, and is unlikely). We could be moved to the 4 day work week. On top of that, there are many (15+ models from major manufactures) PHEV and EV's coming onto the market within the next 5 years (and yes I drove one, they are good commuters).

Bottom line, within 5 Years, I believe that gasoline demand could drop by 25%, easily. However, diesel demand would be struggling to drop by 10%. There are just way more alternative to gasoline than there are to diesel.

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roy on August 21, 2008 - 6:32pm Permalink | Subthread | Parent | Comments top

Even if it did happen, it would only drop highway truck consumption by ~5% (going from 75 to 55) and less freight would be delivered.

Five percent seems way too low for the speed change. Got any actual data?

This article says going from 65 to 75mpg raised fuel consumption
by 27%!

http://www.greencarcongress.com/2008/05/us-trucking-ind.html

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Pitt the Elder on August 23, 2008 - 8:39am Permalink | Subthread | Parent | Comments top

This article says going from 65 to 75mpg raised fuel consumption by 27%!

That's probably true in general. Air resistance increases roughly as the square of speed, and so is 33% higher at 75mph than 65mph.

Wyoming, above, suggested a 20% reduction in consumption from the 30% lower wind resistance at 55mph vs. 65mph, which also seems reasonable, as one would expect non-wind factors to be larger at lower speeds.

Either way, though, there are quite substantial fuel savings to be had from reducing speed a modest amount.

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156 comments on Oil Demand Destruction & Brittle Systems

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