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7.5 kWh of electricity to produce a gallon of gasoline?

Posted: Wed Jul 21, 2010 9:28 pm
by indyflick
I've read numerous reports where Nissan have stated that "it takes 7.5 kWh of electricity to produce a gallon of gasoline". Of course it's obvious then we could simply skip the gasoline production and instead use the 7.5 kWh of electricity to propel the Leaf 30 miles.

I would like to know if Nissan have a white paper available which shows how they derived the "7.5 kWh of electricity to produce a gallon of gasoline" figure. There are some on the Internet who say it's actually more like 12 to 13 kWh. Other say it's 5 kWh. Still others say its less than 1 kWh.

Re: 7.5 kWh of electricity to produce a gallon of gasoline?

Posted: Wed Jul 21, 2010 9:32 pm
by evnow
Very interesting - I've never seen this before. This would be an extremely good rebuke to all those EV critics.

Re: 7.5 kWh of electricity to produce a gallon of gasoline?

Posted: Wed Jul 21, 2010 10:20 pm
by evnow
Instead of kwh to produce gas - look at EROEI of oil. That is between 10 and 20 now.

There is 44.5 KwH per gallon of crude - so it would take 2 to 4.5 kwh to produce oil. Further out of 100 barrels that go into a refinery only 73 barrels of transportation fluids come out.

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Re: 7.5 kWh of electricity to produce a gallon of gasoline?

Posted: Thu Jul 22, 2010 1:39 am
by planet4ever
I saw that 7.5kWh figure on a Nissan information pedestal last December when the Leaf came through San Jose on its first tour. I found it hard to believe, and did some research. I can't find my numbers now, but I think I came up with an estimate of between 0.5kWh and 0.8kWh. I sent feedback to Nissan saying I thought their value was wrong, and wondering if someone might have accidentally slipped a decimal place in their calculation. I got an automated acknowledgment of receipt, but no response. I also never saw the claim again after that.

Re: 7.5 kWh of electricity to produce a gallon of gasoline?

Posted: Thu Jul 22, 2010 8:00 am
by evnow
planet4ever wrote:I can't find my numbers now, but I think I came up with an estimate of between 0.5kWh and 0.8kWh.
Depending on the methodology involved you can get widely varying numbers. Important number is really EROI - as long as that number is high, it doesn't matter. Afterall out of a barrel of oil, you could use a few gallons to get that much power.

BTW, EROI of wind & solar aren't much better.

Re: 7.5 kWh of electricity to produce a gallon of gasoline?

Posted: Thu Jul 22, 2010 8:21 am
by LEAFer
evnow ... interesting info ... do you have a link to more info and background for that graph ?

Re: 7.5 kWh of electricity to produce a gallon of gasoline?

Posted: Thu Jul 22, 2010 8:37 am
by evnow
LEAFer wrote:evnow ... interesting info ... do you have a link to more info and background for that graph ?
This work is by Prof Cutler Cleveland & Prof Charles Hall. Search "eroi oil hall Cleveland".

http://www.theoildrum.com/node/3786 - this 6 part series explains why EROI matters.

Re: 7.5 kWh of electricity to produce a gallon of gasoline?

Posted: Thu Jul 22, 2010 9:33 am
by indyflick
For this conversation I'm only interested in exploring the source of the "7.5 kWh of electricity to produce a gallon of gasoline" statistic. I wish Nissan would provide a whitepaper or even a FAQ statement as to how the statistic was derived. If provable it quickly cuts through all the FUD being thrown around out there that electric cars simply moves the fuel problem to coal.

planet4ever... here's a photo of the Nissan information pedestal you were talking about.

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Re: 7.5 kWh of electricity to produce a gallon of gasoline?

Posted: Thu Jul 22, 2010 9:39 am
by DaveEV
Looks like the 7.5 kWh number has been floating around a while now, but no idea where it actually came from. See this article from September 2009:

Watt’s Next: Your Thoughts

Re: 7.5 kWh of electricity to produce a gallon of gasoline?

Posted: Thu Jul 22, 2010 10:50 am
by indyflick
Thanks drees, nice find.

Here some other data points which may help triangulate on the solution.)
Electricity consumption by petroleum refineries in the US in 2005 was 48,891,000,000 kWh (latest stats I could locate)
Gasoline makes up 45% of the refined products. So we could say gasolines portion the electricity consumed is 22,000,950,000 kWh (48,891,000,000 kWh * 0.45)
So now if I can locate the total amount of gasoline produced in the US in 2005 I think we'll have a defensible statistic.