7.5 kWh of electricity to produce a gallon of gasoline?

[evnow]

Interesting report, thanks for the pointer. I have a couple of questions. First, I assume you calculated this from 14% of 36.6 kWh per gallon of gasoline, correct? That would be 5.124 kWh. But how did you derive the 14%? It looks like 8% in the chart, what am I missing?

I used the chart that shows 14% and 16% for petrol & diesel. This is total WTT energy.

Second, I believe MJ/MJ means the megajoules of energy required to produce an energy product which has one megajoules worth of stored energy, correct? The study says (on page 17) that gasoline MJ/MJ is 0.08. I read in this article that's it's more like 0.20 to 0.25 and gasoline from shale is 0.56 to 0.87!

That 0.08 (or 8%) is just refining. They have used marginal energy needed. Shouldn't matter whether the source is really from shale or not. For shale, the production would use up a lot of energy ...

ps : Whenever anyone takes the "worst case" of coal only for EVs, we should compare to shale sourced petroleum. Afterall increasingly that is where our oil in NA comes from.

 

[indyflick]

Interesting report, thanks for the pointer. I have a couple of questions. First, I assume you calculated this from 14% of 36.6 kWh per gallon of gasoline, correct? That would be 5.124 kWh. But how did you derive the 14%? It looks like 8% in the chart, what am I missing?

I used the chart that shows 14% and 16% for petrol & diesel. This is total WTT energy.

Second, I believe MJ/MJ means the megajoules of energy required to produce an energy product which has one megajoules worth of stored energy, correct? The study says (on page 17) that gasoline MJ/MJ is 0.08. I read in this article that's it's more like 0.20 to 0.25 and gasoline from shale is 0.56 to 0.87!

That 0.08 (or 8%) is just refining. They have used marginal energy needed. Shouldn't matter whether the source is really from shale or not. For shale, the production would use up a lot of energy ...

ps : Whenever anyone takes the "worst case" of coal only for EVs, we should compare to shale sourced petroleum. Afterall increasingly that is where our oil in NA comes from.

Excellent point. It's self evident oil is getting scarce. They wouldn't be going to deeper and deeper water nor using NG to process oil shale if there were "easy pickin's" available. By the way, do I have the MJ/MJ idea right?

 

[evnow]

By the way, do I have the MJ/MJ idea right?

Yes.

 

[PaulScott]

When I saw this number earlier this year, I contacted Tim Gallagher to confirm they had this documented. Turns out they didn't. The best numbers I've seen indicate about .8 - 1.0 kWh of actual electricity is used per gallon, but there is a lot of natural gas used, too. The NG, if used in a combined cycle plant, the number of kWh would probably approach 7.

 

[indyflick]

When I saw this number earlier this year, I contacted Tim Gallagher to confirm they had this documented. Turns out they didn't.

Are you saying he hadn't documented where they located the data point or how they internally derived it?

 

[AndyH]

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.

FWIW: http://gatewayev.org/how-much-electricity-is-used-refine-a-gallon-of-gasoline

Subject: Energy to refine gasoline

Dear Mr. Armstrong,

Thank you for your December 4, 2009, electronic mail requesting a reputable source to calculate the energy required to refine a gallon of gasoline. The energy required to refine a gallon of gasoline can be estimated based on the energy content of crude oil and the refinery efficiency of the facility performing the energy conversion; I can provide you a reputable source for both values.

In a 2008 report, Argonne National Lab estimated that the efficiency for producing gasoline of an “average” U.S. petroleum refinery is between 84% and 88% (Wang, 2008), and Oak Ridge National Lab reports that the net energy content of oil is approximately 132,000 Btu per gallon (Davis, 2009). It is commonly known that a barrel of crude oil generate approximately 45 gallons of refined product (refer to NAS, 2009, Table 3-4 for a publication stating so). Thus, using an 85% refinery efficiency and the aforementioned conversion factors, it can be estimated that about 21,000 Btu—the equivalent of 6 kWh—of energy are lost per gallon of gasoline refined:

The documents referenced herein are publicly available, as follows:

Wang, M. (2008), “Estimation of Energy Efficiencies of U.S. Petroleum Refineries,” Center for Transportation Research, Argonne National Laboratory, http://www.transportation.anl.gov/m...dfs/energy_eff_petroleum_refineries-03-08.pdf

Davis, S., Susan W. Diegel, and Robert G. Boundy (2009), Transportation Energy Data Book, edition 28, National Transportation Research Center, Oak Ridge National Laboratory, cta.ornl.gov/data/

NAS (2009), Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use, The National Academies Press, http://www.nap.edu/openbook.php?record_id=12794&page=1

It is worth noting that refining one barrel of oil yields gasoline in addition to other products, so only a portion of the refining energy used to refine a barrel of crude is truly attributable to gasoline. Even so, in terms of energy equivalencies, the preceding estimation is valid.

If I may be of further assistance, please do not hesitate to contact me. Your interest in energy efficiency at the Department of Energy is appreciated.

Sincerely,

Jake

– Jacob Ward Program Analyst/PMF Vehicle Technologies Program Office of Energy Efficiency and Renewable Energy U.S. Department of Energy

 

[indyflick]

Excellent find Andy! That is really good data. I found a free version of the Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use that you can download.

 

[AndyH]

Excellent find Andy! That is really good data. I found a free version of the Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use that you can download.

Excellent - thanks!

The info flowed thru the local EAA chapter yesterday and I thought of this thread. Enjoy!

 

[planet4ever]

Am I not understanding this correctly? It sounds as if they are saying that due to refining inefficiencies the manufacture of gasoline is losing the equivalent of 6kWh of electricity. That is very different from saying that they are actually consuming 6kWh for every gallon produced.

Surely no one is claiming that the generation of electricity is 100% efficient. Why should we fault the oil companies for having some loss in its generation of gasoline?

Note please: I am not an apologist for big oil, and indeed I dream of the day when no oil at all is used for transportation. But I believe we should use fair criticisms of our oil addiction and, so far at least, I am not convinced that the 7.5kWh/gallon accusation is fair.

 

[evnow]

Surely no one is claiming that the generation of electricity is 100% efficient. Why should we fault the oil companies for having some loss in its generation of gasoline?

Nobody is saying this is someone's fault. It is just a fact you need to consider when figuring out the whole carbon footprint or EROI.

 

[DaveEV]

Am I not understanding this correctly? It sounds as if they are saying that due to refining inefficiencies the manufacture of gasoline is losing the equivalent of 6kWh of electricity. That is very different from saying that they are actually consuming 6kWh for every gallon produced.

Surely no one is claiming that the generation of electricity is 100% efficient. Why should we fault the oil companies for having some loss in its generation of gasoline?

Note please: I am not an apologist for big oil, and indeed I dream of the day when no oil at all is used for transportation. But I believe we should use fair criticisms of our oil addiction and, so far at least, I am not convinced that the 7.5kWh/gallon accusation is fair.

That was kind of my thoughts as well - it's not just electricity that is counted in that number, but all external energy inputs compared to what comes out.

The actual answer appears to be in here: http://www.transportation.anl.gov/modeling_simulation/GREET/pdfs/energy_eff_petroleum_refineries-03-08.pdf

For example, in 2006, refineries bought 39,353 million kWh which accounted for about 3.5% of the total process fuels used to refine fuel - or about 0.260 kWh per gallon of gas.

Now, what that doesn't take into account is how much electricity could be generated with the other process fuels. For example, natural gas was 38% of process fuels (697,600 million cubic feet). Given that a modern natural gas can convert gas to electricity at 50% efficiency or better, about 20% of the total process fuels or 1.5 kWh / gallon.

The other big chunks of energy (39%) comes from still gas and petroleum coke (14%) - both of which are refinery byproducts. So it may not be fair to count them, either.

In the end - it's a bit complicated - on one hand you have 0.26 kWh of direct electricity input per gallon - on the other hand, you have 7.5 kWh/gallon of extra energy inputs per gallon which would have various conversion efficiencies if turned into electricity with efficiencies at best of 50% or so.

 

[indyflick]

Am I not understanding this correctly? It sounds as if they are saying that due to refining inefficiencies the manufacture of gasoline is losing the equivalent of 6kWh of electricity. That is very different from saying that they are actually consuming 6kWh for every gallon produced.

Surely no one is claiming that the generation of electricity is 100% efficient. Why should we fault the oil companies for having some loss in its generation of gasoline?

Note please: I am not an apologist for big oil, and indeed I dream of the day when no oil at all is used for transportation. But I believe we should use fair criticisms of our oil addiction and, so far at least, I am not convinced that the 7.5kWh/gallon accusation is fair.

It's not refining inefficiencies, it's MJ/MJ. Its the amount of energy into the process for the amount of energy product out. It requires energy to refine the oil into hydrocarbon products like gasoline. 84% to 88% is a big improvement from decades ago. It could never be 100%, because crude oil isn't going to spontaneously turn itself into gasoline.

 

[planet4ever]

I understand, but I think drees has the correct attitude here - it's complicated. What I was complaining about was the implied argument, which was actually stated explicitly by Nissan on their tour a year ago, that it is ludicrous to refine gasoline, because you use as much electricity creating the gasoline as it would take to drive a LEAF the same distance. As soon as you start justifying by using energy equivalents, that argument falls apart.

 

[indyflick]

As soon as you start justifying by using energy equivalents, that argument falls apart.

I don't think the argument falls apart, it just may not be as EV advantageous, as was initially stated by Nissan. Clearly there's still a trade off for where the energy can best be utilized. In this thread, I think we have come to the conclusion that evnow was correct from the start, Nissan was really talking about kWh of energy in total not just electricity. While we are all accustomed to seeing electricity stated in kWh, most people don't know you can state any energy source in kWh. Nissan should have stated something like "it takes 7.5kWh of energy to refine a gallon of gasoline..." Then state how many miles the LEAF could travel based on that much energy. To further complicate matters, you would also need to analyze the situation over a specific period, for example calendar year 2009, because we learned oil refiners constantly trade off for the cheapest energy sources to produce their products.

Here are my key takeaways.

• We need to get people aware that gasoline doesn't magically flow from filling station pumps, like water from a mountain stream. It takes a lot of energy from well to wheels.
  We are trading off that energy to make gasoline which some of it could be making electricity
  Nissan needs to have a few simple whitepapers developed which simplify the argument.

 

[smkettner]

What really counts is how much electricity is supplied direct from the grid that would be otherwise be available to the EVs.

 

[sproqitman]

@indyflick: Thank you. The light bulb finally went on in my head. So, 6 (or 7.5) KWh of energy go into turning petroleum into a gallon of gasoline. That energy can be used to make gasoline, or it can be used to make other things, such as electricity. That gallon of gasoline will propel the average car 25-30 miles. The same energy, converted to electricity, would propel the LEAF 25-30 miles.

Petroleum can be used to make other things besides gasoline. Tupperware, roofing material, sunglasses, deodorant (list here: http://www.energytomorrow.org/Petroleum_Products.aspx). Gasoline can only be made from petroleum. Electricity, on the other hand, can be made from a variety of sources.

 

[evnow]

What really counts is how much electricity is supplied direct from the grid that would be otherwise be available to the EVs.

Not necessarily - the NG can be better used to generate electricity in a cleaner way compared to coal.

But, I think we should start concentrating on oil from tar sands.

What is the worst electricity ? Coal.

What is the worst oil ? Tar sands.

If anyone mentiones electricity only from coal - my counter argument would be
- Even Prius running on Oil from Tar sands is worse
- As and when the grid gets cleaner, EVs automatically get cleaner. The Grid is progressively getting cleaner. But oil is getting progressively worse - as deep ocean & tar sands oil will only get bigger in % in the future ...

 

[smkettner]

Maybe this EV thing is part of the reason why new oil refineries are not being built.
Demand for gasoline and a few other product might start to level off or even wane a bit as EVs become more prevelent.
Certainly not the entire reason, just saying a thought.

 

[Ready2plugin]

What really counts is how much electricity is supplied direct from the grid that would be otherwise be available to the EVs.

Not necessarily - the NG can be better used to generate electricity in a cleaner way compared to coal.

But, I think we should start concentrating on oil from tar sands.

What is the worst electricity ? Coal.

What is the worst oil ? Tar sands.

If anyone mentiones electricity only from coal - my counter argument would be
- Even Prius running on Oil from Tar sands is worse
- As and when the grid gets cleaner, EVs automatically get cleaner. The Grid is progressively getting cleaner. But oil is getting progressively worse - as deep ocean & tar sands oil will only get bigger in % in the future ...

I love that counter argument!! Hope you don't mind that I use it too!

 

[indyflick]

Maybe this EV thing is part of the reason why new oil refineries are not being built.
Demand for gasoline and a few other product might start to level off or even wane a bit as EVs become more prevelent.
Certainly not the entire reason, just saying a thought.

It's true new oil refineries aren't being build in the U.S. Big Oil loves to drag out that old argument when gas prices are going up and use it as the reason why. They say it's the fault of the environmentalist. This is of course goes beyond FUD, it's total BS. They actually continue to add capacity to their existing refineries, so they don't need to build new ones. Also their existing refineries continue to get more efficient. And finally, demand for gasoline has been fairly flat for the past sevral years. Why add a lot of capacity if there's no additional demand?

You would think those people railing against the LEAF would instead thank us. We won't be competing with them for their gasoline. Therefore, there will be more to go around. And, as you point out, as EV owners become larger in numbers, gasoline prices would likely fall. Unfortunately that might create additional demand for gasoline, but that's a whole other discussion.