Ergamines
I don’t think we can go just from 684 bicycle mpg to a day’s labor, an ergamine. Who knows how long the average person can ride, every day, without blowing up. Instead, I’m going to look at what a hard working person burns in a day, and then assume (yuck) that he can work some number of days sipping oil as his energy source (at least all the oils have similar calorie values, peanut or olive oil might be more palatable than the typical soybean biodiesel … not that I know!).
I know that backpackers work hard all day and have to know how much food to bring. Checking their pages, I see 4,000 calories per day as typical.
I also found a “calories per day calculator” that allows even more fine tuning. It looks like a large active male burns 3000-4000 calories per day. Let’s assume our ergamines are very active and stick with 4000.
A gallon of soybean oil contains 30800 calories, or enough to power an ergamine for 7.7 days … call it a week, or say that one gallon of oil contains 7 or 8 “energy slaves” to work for you one day.
Taking the inverse of that, one ergamine is about 1/8 gallons, or … one pint! It looks like my calculation of an ergamine is a bit bigger than Mr. Chomat’s drop (or gram), but it is an easy to remember amount.
The “energy slaves” thing is pretty common on the web. It is usually quoted as how many slaves we each have “following us around every day.” We’re not there yet … and I’m not sure that is the important part.
It might be more important to note that the real difference (as E-P noted) is speed of consumption. If it is just me, with no real slaves (or to use a more gentle term, workers), there is a limit to how fast I can consume that oil and convert it to work. My limit is probably 4000 calories, or one pint, per day. On the other hand, I can fire up a machine and burn as much as I want, in as short a time as I want. I can row a boat across the Pacific (sipping soybean oil all the way) or I can fire up a biodiesel yacht and enjoy the cruise.
I think the real question, in the spirit of Mr. Chomat’s book, is how much of a hurry are we in? How fast do we want to go, and how many day’s labor do we want to compress into a morning commute? Which is better, to fuel your biodiesel truck for a morning, or your bike for a month?
October 10th, 2005 at 10:47 am
I dug up some stuff on electric bike energy consumption; they claim a best-case of 8 Wh/mile and worst of 32.
At 30800 kcal/gallon and perhaps 30% conversion efficiency, a gallon of soybean oil might yield 10.7 kWh. At the 8 and 32 Wh/mi extremes, the gallon would drive an electric bicycle between 336 and 1342 miles. (I guess mitochondria aren’t the best conversion machinery in the world…)
More to the point, a 1 m^2 solar panel producing 120 watts could drive the bike at between 3.75 and 15 MPH as long as it was in full sun.
October 10th, 2005 at 12:37 pm
It’s interesting that 684 is right in there between 336 and 1342. Maybe that reinforces the similarity in efficiency of human and mechanical consumption.
On the survace the mitochondria beat some electric bikes, but not all. Maybe if we put a human on the a bike (and at a speed?) equivalent to the [most efficient] test vehicle he could do as well.
For both humans and these electric bikes, I notice that it is often long-and-slow or short-and-fast.
I think electricity will really start to shine when we think about what fuels actually cost for man and machine. When it is bagels vs. the wall outlet, I’m sure the wall outlet wins!
October 10th, 2005 at 12:38 pm
I plan a “bicycle fuel efficiency” post about food costs tomorrow.
October 10th, 2005 at 1:53 pm
Your geometrics are so mean! ;-)
October 11th, 2005 at 11:21 am
:(
January 27th, 2006 at 3:58 am
Hi Odograph!
Just read your posting via TOD – a fascinating topic, though I prefer metric to Imperial. Here’s my own version:
1 metric tonne of olive oil (or any veg. oil) contains approx. 9 million calories.
Now some four-function math.
If an average semi-sedentary male consumes approx. 2400 calories a day, he can survive for 3650 days on 1 metric tonne. Equals ten years (I rigged the ergamine to get a neat outcome).
We’re not all backpackers, BTW!
Thanks also for introducing readers to the term ‘ergamine’. Who invented it?
Cheers,
Carolus.
January 27th, 2006 at 10:23 am
I first read of “ergamines” in the book called “Oil Addiction†by Pierre Chomat. I think it’s his term, but he comes up with somthing like “one drop or gram” of oil equals one ergamine. I’m not getting that result at all.
BTW, with respect to backpackers & etc, I think the ergamine is really supposed to be the “hard labor” equivalent. Or as is often termed “energy slaves.”
Up above E-P says my “geometrics are so mean!” … he might be referring to how hard I push my ergamines ;-)