I do remember seeing a graphic representation  of the potential explosive power of a cup of gasoline, equal to some impressive tonnage of TNT. Given the right mix etc y'know or something. It was trying to illustrate how little of the fuel's potential actually is harnessed in throwing us down the highway.

 islander wrote: 


Yes. Actually, this was pretty much exactly the response I was hoping for. The claim just seemed unlikely to me, but I was too lazy to go beyond that. Glad people did.

 NoEnzLefttoSplit wrote: 
Pee-ewwww.

 NoEnzLefttoSplit wrote: 
Hey Man, nice shot!

 fidget wrote: 
Not really a war, just a good sanity check.  It's good to help us all keep our BS detectors tuned up. In addition to spotting the BS, the ability to validate or dispute claims needs practice now and then.

 NoEnzLefttoSplit wrote: 
Maybe Saturday. But we've got this cold north wind for the next ten days I believe. Good thing I've got a woodstove and plenty of logs

Seriously
"that ties in pretty well with the macro figures for energy consumption of the full economy broken down into transport, industry, and home use. "

 fidget wrote: 
toes

hmph.

Speaking of which, how's the snow?

 hobiejoe wrote: 
Sheesh! I was just quoting a random fact I read on the QI website - I didn't mean to start a war.

As I said before "OK, maybe it's not even a fact" 

But, it is great to see everyone getting their calculators out

 islander wrote: 
that ties in pretty well with the macro figures for energy consumption of the full economy broken down into transport, industry, and home use.

 islander wrote: 
I guess we're not trying to bomb down the motorway at 85mph in the house.

 hobiejoe wrote: 
UK gallon = 1.2 US gallon

UK household = ? harder to find, but looks like ~0.9KW (my US number was actually high, looks like it should have been closer to 1.2KW)

so we get:18 days at 100% efficiency.

Note: this is in the right ballpark. My generator at home is a 5KW unit that will run more than 12 hours on just under 3 gallons of fuel. So if we say 25% conversion efficiency that is just under 2 days for 10 gallons. Which would be 8 days w/ 100% efficiency. 

So on a purely energy content basis, a car holds enough energy for just over a week for an average house.  Interesting to consider that if we fuel up ~ once a week, our car energy use and our household energy use are roughly equivalent. 

 

 hobiejoe wrote: 
ha! now that is what I call fusion!

back at you K!

The QI forum is about 90% deeply sceptical on this one   As I flunked chemistry and physics I have nothing to add.

One of the posters seemed to think this might be it.  It could be written in chinese and it'd make more sense to me.

According to google, 10 Imperial gallons = 0.0454609188 metres cubed, and acccording to wikipedia petrol has a density of 719.7 kg/m3. So, 10 gallons of petrol has a mass of 32.72kg. As we know, E=mc^2, so if it were converted to energy with 100% efficiency it would give 2,940,726,944,826,867,318.08J = 8.2 × 10^11 kWh. If you can't run a house for five years on that I'd be amazed.

/mrshj

 

 NoEnzLefttoSplit wrote: 
In which case I wonder if we can hook C's botty-burps to a generator and earn some feed-in tariff wonga
 
 

Heinz meanz beanz and beanz meanz methane.

Just saying.

 islander wrote: 
UK gallon

UK household

probably gives you different numbers.............but not different enough

I think we are starting from the wrong place though- that was just someones opinion about how the number was derived- is that correct Simon?

/mrshj

 fidget wrote: 
Basic numbers and algebra:

Gasoline = 114,000 BTU/Gallon

3413 BTU = 1 KWHr

10 Gallons = ~334 KWHrs

Average US household load = ~ 1.5 KW

24 hours / day

Energy content of 10 Gallons of gasoline = ~ 9.25 days of household use. That is with 100% conversion efficiency (which doesn't happen). 

 fidget wrote: 
More, this is from the forum

"Your average car engine ( say a 1.6 litre ) produces say 100 BHP. 100 BHP equals roughly 78 Kilowatts. If the engine consumes 3 gallons per hour at maximum output ( equivalent to the car doing a top speed of 135 miles per hour, at 35 miles per gallon, for three hours and 20 minutes ), then the car produces 78 Kilowatts times 3.3, i.e 257.4 Kilowatt hours in total. The average house uses around 5000 Kilowatt hours per annum, thus even with no efficiency losses in converting the crankshaft output of the engine to generated electricity ( which is physically impossible ! ), you would need 20, yes TWENTY 10 gallon tanks of petrol to do the job. Even if you could invent a much more thermodynamicaly efficient engine, and recoop of all the wasted energy from the engine ( most petrol internal combustion engines are about 40 percent efficient ), you would still need 8 times 10 gallon tanks of petrol, i.e 80 gallons. So 400 gallons for 5 years with a perfect ( impossible ) energy transfer, 0r 1000 gallons more realistically...£ 5460 !!! oddly very similar to current electricity costs ( at the high end ), or considerably more. In short I think this claim is nonsense"

OK, maybe it's not even a fact

 fidget wrote: 
Until I see some assumptions and calculations I'm still a bit skeptical.  Perhaps they figured out the mass of the gasoline and converted it all to energy using E = mc².

 fidget wrote: 
I reckon there's more to it than that - something like : If you stick a match to it, in theory x amount of energy will be released. In reality not all of the potential energy is released, and worse, if burn it more slowly, inefficiencies increase, and then there's all the losses in converting that energy into electricity.

Something like that, anyway..... it sounds a bit theory vs. reality.