[thorn]

I'm reading John Howe's book End of Fossil Energy. I was just thinking about the energy equivalent of gas. He says that 1 gal of gas is equal to about 600 man hours (if I remembered right). Which at $3/gal is less than $0.01/ hour. Who would work for $0.01/ hour? That's amazing if you think about it. It does not seem like there is that much energy in a gal of gas. Makes you realize that we really are screwed!

[Free]

Roscoe Bartlett used another example in his speach, that the energy output of one barrel of gasoline equals that of twelve men working for one year.

According to www.eroei.com the energy which is set free at the combustion of 1 gram of gas is 50000 Joule, while that of TNT is around 4000 Joule. One Joule is the energy you need to to lift ca. 100 gram (one small apple) for 1 metre.

I think Deffeyes uses the example that a plane full of American tourists visiting the pyramids uses as much energy as went into said pyramids in human labor.

[falser]

600 man hours sounds a little high. What is the official definition of a man-hour? One gallon of gas can move a 2000lbs car 25 miles. 600 hours = 25 days. I bet 3 people could push a car the same distance in a lot less than 25 days, probably more like 2 days (48hr) max. So my guesstimate would be 3 people X 48 hours = 144 man hours.

[MD]

Start with the assumption that a man can produce 250 watts continuously. That makes a kilowatt hour every 4 hours. At $.15/kwh electricity, that makes you worth about $.035 per hour.

The pushing a car example only works if you consider how far the galosile can push the car at a walking pace. The 600 man hour figure is probably about right.

It all points to how profoundly cheap energy has been, and what a shock it will be when we have to pay 10 or 100 times as much.

Slavery will return with a vengeance. Hell, we already have the slave equivalents in Asia making all our crappy consumer goods for WalMart.

The future of America will feature the return of the 16 hour 6 day work week for the common laborer. Some slaves have had better lives!

[bobbyald]

1 Gallon = 132,000,000 Joules = 125,000 BTU = 36,650 Watt Hours = 31,000 Calories = 110 McD Hamburgers = .......

[jdmartin]

600 man hours sounds a little high. What is the official definition of a man-hour? One gallon of gas can move a 2000lbs car 25 miles. 600 hours = 25 days. I bet 3 people could push a car the same distance in a lot less than 25 days, probably more like 2 days (48hr) max. So my guesstimate would be 3 people X 48 hours = 144 man hours.

No way could 3 people push a car 25 miles in 2 days. Whether it would take 25 days or not, I have no idea, since it would much depend on the terrain, weather, and the physical makeup of the men.

Besides that, a gallon of gas can move a 2,000 lb car further than 25 miles. Hell, my pickup weighs 5,000 lbs plus and gets 20mpg on the highway in lightly mountainous terrain. I would guess that 2,000 lb car is more like 35 miles in hilly areas, 40 in the flatlands.

But let's just use my truck, since I know what it gets. No way could 3 people push my truck 20 miles in 2 days.

[UIUCstudent01]

600 man hours sounds a little high. What is the official definition of a man-hour? One gallon of gas can move a 2000lbs car 25 miles. 600 hours = 25 days. I bet 3 people could push a car the same distance in a lot less than 25 days, probably more like 2 days (48hr) max. So my guesstimate would be 3 people X 48 hours = 144 man hours.

25 miles to me means just about a full day of walking (sunrise to sunset)... and on full day of walking (of hilly terrain) left me with calluses..

I've never pushed a car - so I don't know how much resistance there will be, but I assume it's considerable. I'm very sure 3 people wouldn't do it in 144 man hours...

Then there's the fact that you gotta eat + sleep + take breaks. It may not count - but it sure will double the amount the amount of time that it will take to complete a task.

(Of course this kind of talk is kinda meaningless - we have horses, donkeys and oxen or something to carry and push crap in the past. But, of course, not everyone can have one.)

[ohanian]

1 Gallon = 132,000,000 Joules = 125,000 BTU = 36,650 Watt Hours = 31,000 Calories = 110 McD Hamburgers = .......

132E6 joules / 250watt / 3600 sec = 146 man hours

based on 1 man hour = 250 watt * 1 hour (3600 seconds)

Oh by the way. See how wonderful the metric system is.
It's easy to convert from joules to watts * seconds

1 joule = 1 watt * 1 second (piss easy)

And if you work your guts out for 8 hours a day, your energy
comsumption is

8hr * 3600secs/hr * 250watt = 7.2E6 joules (7.2 megajoules)
which is 7.2E6 joules / 4184 (joules/kilocalorie) = 1,720 kilocalorie
or 1,720 Big calories (1720 Cals)

The good thing about using joules in dieting is that you can never
confuse Big calorie with Small calorie.

This is because

A jew is a jew is a jew.

Oops!

I mean, a joule is a joule is a joule.

According to Wikipedia, a litre of petrol contains 29 megajoules of energy.

1 US gallon = 3.78 litres = 3.78 * 29E6 joules = 109E6 joules

This is close enough to the 132E6 joules described above.

Of course a modern car has 18% efficiency so only 18% of the energy
of the fuel gets converted to useful kinetic energy.

[Ludi]

The future of America will feature the return of the 16 hour 6 day work week for the common laborer.

Except there's no need to work that hard to provide for our needs, if we choose to work cooperatively. Though many people here seem to find the idea of cooperation so offensive that they would rather return to a feudal society than an egalitarian one.

[thorn]

1 Gallon = 132,000,000 Joules = 125,000 BTU = 36,650 Watt Hours = 31,000 Calories = 110 McD Hamburgers = .......

132E6 joules / 250watt / 3600 sec = 146 man hours

based on 1 man hour = 250 watt * 1 hour (3600 seconds)

I assume that is at 100% efficiency...I guess a car is what, 33%? (well to wheels)

[kmann]

600 man hours sounds a little high. What is the official definition of a man-hour? One gallon of gas can move a 2000lbs car 25 miles. 600 hours = 25 days. I bet 3 people could push a car the same distance in a lot less than 25 days, probably more like 2 days (48hr) max. So my guesstimate would be 3 people X 48 hours = 144 man hours.

25 miles to me means just about a full day of walking (sunrise to sunset)... and on full day of walking (of hilly terrain) left me with calluses..

I've never pushed a car - so I don't know how much resistance there will be, but I assume it's considerable. I'm very sure 3 people wouldn't do it in 144 man hours...

Then there's the fact that you gotta eat + sleep + take breaks. It may not count - but it sure will double the amount the amount of time that it will take to complete a task.

(Of course this kind of talk is kinda meaningless - we have horses, donkeys and oxen or something to carry and push crap in the past. But, of course, not everyone can have one.)

You're right on that point. It doesn't really matter whether three men can move a car x miles in y hours. The important point is petroleum does a lot of work for us. And the question is what will we do when it's no longer obtainable.

[thorn]

The important point is petroleum does a lot of work for us. And the question is what will we do when it's no longer obtainable.

A lot less!!

[dukey]

i think there are too many variables to say exactly 1 gallon of gas = 600 man hours ..

but i think its safe to say there is a shit load of energy in a gallon of gas.
Only have to look at farming to see this ..
what would take a team of men and horses days to do a couple of tractors and a combine can do in hours !

[WisJim]

I thnk that my son's Honda VX weighs about a ton (2000 pounds) or a bit more, and can get 50mpg (or better) on the hiway if you drive carefully and it is good tune. It will get better mileage at a walking pace!
A vehicle designed to move a ton at a walking pace wouldn't need much power, and would make the man hour/gallon of gas comparison even more lopsided.

Jim

[turn74]

I'm reading John Howe's book End of Fossil Energy. I was just thinking about the energy equivalent of gas. He says that 1 gal of gas is equal to about 600 man hours (if I remembered right). Which at $3/gal is less than $0.01/ hour. Who would work for $0.01/ hour? That's amazing if you think about it. It does not seem like there is that much energy in a gal of gas. Makes you realize that we really are screwed!

thorn- What do you think of the book? I watched that video from that link you posted.

Thanks!

Bob

[thorn]

I'm reading John Howe's book End of Fossil Energy. I was just thinking about the energy equivalent of gas. He says that 1 gal of gas is equal to about 600 man hours (if I remembered right). Which at $3/gal is less than $0.01/ hour. Who would work for $0.01/ hour? That's amazing if you think about it. It does not seem like there is that much energy in a gal of gas. Makes you realize that we really are screwed!

thorn- What do you think of the book? I watched that video from that link you posted.

Thanks!

Bob

It is a good simple book on PO, right to the point. A coworker borrowed it and it gave him a much better understanding of PO. He has some solutions ie slow down transportation, 5% decrease in fossil fuels every year etc and switch to RE. Of course not much time left! Also more details on his solar tractor and gulfcart. He lists lots of web sites and PO books too. A good read for someone who knows very little about PO, good to loan to friends and nonbelievers.

John Howe is coming to speak at Bartlett's energy conference :

http://www.bartlett.house.gov/Events.asp



--Greg

[Bandidoz]

Start with the assumption that a man can produce 250 watts continuously.

That's VERY optimistic! If you try using a pedal generator, or an exercise bike, you'll find that you can only continuously generate 100W.

You can do 250W in short bursts; you'd have to be extremely fit to be able to do that continuously. I'm not sure whether an Ironman triathlete could be able to maintain that power level.

[MD]

The future of America will feature the return of the 16 hour 6 day work week for the common laborer.

Except there's no need to work that hard to provide for our needs, if we choose to work cooperatively. Though many people here seem to find the idea of cooperation so offensive that they would rather return to a feudal society than an egalitarian one.

The "doomer" set does seem to assume feudalism post peak, which would be an unfortunate outcome. Given human history though, that outcome is likely.

[nero]

A gallon of gas can't push a car 25 miles either! Just try it, you'll just make a puddle. You've got to put the gallon of gas in the gas tank and burn it in the engine. Now I would put to you that if you took three men and (with a bit of TDP) put them in the gas tank they would be able to propel the car alot further than 25 miles.

My point is that if you are pushing the car why the heck would you leave the engine or the transmission in it? Take out all that weight and friction and see how easily it rolls! Without the extra useless weight I bet three men could push a car 25 miles in 2 days easily.

[MD]

Start with the assumption that a man can produce 250 watts continuously.

That's VERY optimistic! If you try using a pedal generator, or an exercise bike, you'll find that you can only continuously generate 100W.

You can do 250W in short bursts; you'd have to be extremely fit to be able to do that continuously. I'm not sure whether an Ironman triathlete could be able to maintain that power level.

I was being very generous. You are correct.