7.5 kWh of electricity to produce a gallon of gasoline?

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indyflick

Well-known member
Joined
Jul 9, 2010
Messages
505
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.
 
Very interesting - I've never seen this before. This would be an extremely good rebuke to all those EV critics.
 
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.

eroei_chart.jpg
 
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.
 
planet4ever said:
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.
 
LEAFer said:
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.
 
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.

7.5kw_to_refine.jpg
 
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.
 
Some stats here on how much refining was done in the US - about 16 mbpd in 2005. Some 6% of gasoline is imported.

http://www.econbrowser.com/archives/2005/09/the_question_ab.html
 
UPDATE... I divided incorrectly in the last step. As pointed out by Rik and evnow, the analysis below is not correct. This analysis actually indicates 22,587,642,000 kWh / 132,488,160,000 gallons of gasoline = 0.17 kWh per gallon of gasoline in the refining process.

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Based on my personal analysis the shows that in 2005 US oil refineries consumed 5.86 kWh of electricity for every gallon of gasoline they produced. That same electricity could instead propel a Nissan Leaf over 20 miles.

Analysis and links

Electricity consumption by petroleum refineries in the US in 2005 was 48,891,000,000 kWh
http://www.nationmaster.com/graph/ene_ele_con_by_pet_ref-energy-electricity-consumption-petroleum-refineries#source

Gasoline composed 46.2% of all US refined oil products in 2005
http://tonto.eia.doe.gov/dnav/pet/pet_pnp_pct_dc_nus_pct_a.htm

Therefore, we take 46.2% of the total electricity used by the US refineries in 2005 for galoline production. So that would be 22,587,642,000 kWh of electricity. (48,891,000,000 kWh * .462)

In 2005 US refineries produced 132.4 billion gallons of gasoline
http://www.eia.gov/dnav/pet/hist/LeafHandler.ashx?n=pet&s=wgfrpus2&f=w

Download the spreadsheet and use the 2005 data on gasoline production. The data is the weekly U.S. Refinery and Blender Adjusted Net Production of Finished Motor Gasoline (Thousand Barrels per Day). So you need to add up the weekly totals, multiply by 7 to get the full weeks, multiply by 1000 (data is thousands), and multiply by 42 because there are 42 gallons in a barrel. That gets you to 132,488,160,000 gallons.

132,488,160,000 gallons of gasoline / 22,587,642,000 kWh = 5.86 kWh of electricity consumed for every gallon of gasoline produced in the US in 2005.

I would still like to know how Nissan came up with their 7.5 kWh of electricity consumed for every gallon of gasoline produced. I doubt refineries have become less efficient over the last five years. But I feel like this quick, back of the napkin analysis, could defend the assertion that at least 5 kWh of electricity is consumed for every gallon of gasoline produced. And the data shows that gasoline production consumes far more electricity than most people realize.
 
indyflick said:
I would still like to know how Nissan came up with their 7.5 kWh of electricity consumed for every gallon of gasoline produced. I doubt refineries have become less efficient over the last five years.

Refineries generally have various sources of energy for refining. They use the cheapest option in any given location & time. The main sources are electricity & natural gas. While electricity rates are controlled and stable, NG rates are not. This makes decision on using NG vs electricity dependent on market rates of NG. Mix of electricity & NG used varies with market rates. NG ofcourse can be used to produce fairly clean electricity. So, it is important to find out total energy used in refining rather than just electricity.
 
So, it is important to find out total energy used in refining rather than just electricity.
I see what you're saying but that is a different analysis. For this analysis I only want the electricity usage. I'm analyzing a past event, I'm not concerned with what the refiners may or may not do in the future due to NG pricing. I understand that if NG pricing goes up, the refiners will move to electricity.

So, in this case, while including the refiners use of NG makes the case even stronger for the BEV, it makes the message more complex because consumers know the BEV can't directly run on NG.
 
Some discussions on this.

http://www.teslamotorsclub.com/showthread.php?t=475

I'll spend a bit of time on this and get some data. There is a ton of data at EIA, IEA, BP etc.
 
indyflick said:
I doubt refineries have become less efficient over the last five years.
I wouldn't be surprised if it had, especially as crude oil gets more "sour" as the light crude runs out.
 
evnow said:
Some discussions on this.

http://www.teslamotorsclub.com/showthread.php?t=475

I'll spend a bit of time on this and get some data. There is a ton of data at EIA, IEA, BP etc.

Nice find. Appears that group have been struggling with question for three years. To your point, it's going to change a bit year over year as the refineries arbitrage electricity and NG. I feel comfortable with the 2005 statistic but I wish we had 2004 through 2009. Then we could average them and go with that.

Again, if Nissan could provide their analysis and sources it would be helpful.
 
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