Pollution: EV vs ICE

[JeffN]

Here is my rebuttal to Robert Llewellyn's Fully Charged "Volts for Oil" episode. Unfortunately, I'm having trouble posting it here as well (I get some SQL error msg) so I will break it down into multiple parts....

Robert,

I'm a Volt owner and am a likely customer for Tesla's future 3rd generation car. I've watched all the episodes of Fully Charged that I'm aware of and they are great. I'm eagerly looking forward to watching future segments.

But.... this recent episode titled "Volts for Oil" on the grid electricity use by refineries in the UK appears to be repeating misleading and inaccurate claims.

You state that the oil industry no longer releases data on this after 2005. Yet I found UK annual data up to 2010 after a few seconds of googling and more recent data is apparently available from the UN in an offline publication.

You also quote some unclear source as saying that it takes about "4.5 kWh of electricity" to refine every gallon of UK gasoline but you don't show the math.

 

[JeffN]

Rebuttal, part 2:

According to data.un.org, UK refineries used 4,459,000,000 kWh in 2005:
http://data.un.org/Data.aspx?d=EDATA&f=cmID%3AEL%3BtrID%3A0925" onclick="window.open(this.href);return false;

And, UK refineries produced 22,620,000 metric tons of gasoline:
http://data.un.org/Data.aspx?d=EDATA&f=cmID%3aMO%3btrID%3a013" onclick="window.open(this.href);return false;

That 2005 UK refinery electricity use is slightly different from the number you use in the program (5,642,000,000 kWh) which also came from the UN, according to you. The numbers vary from year to year and the number you used is almost exactly the same as the UN online 2007 number. In any case, the precise numbers don't matter that much in the scale of the final calculations.

And yes, gasoline is sometimes measured by weight and that converts to around 8,104,621,999 US gallons, according to various sources including this US government conversion calculator:
http://www.eia.gov/kids/energy.cfm?page=about_energy_conversion_calculator-basics" onclick="window.open(this.href);return false;

So, 4459000000 / 8104621999 works out to 0.55 kWh of electricity per gallon of refined gasoline from a UK refinery.

A typical refinery produces 19 gallons of gasoline for every 42 gallons of crude oil or 46% by volume, according to Wikipedia and other sources:

http://en.wikipedia.org/wiki/Gasoline#Energy_content" onclick="window.open(this.href);return false;

Therefore, the energy used in refining needs to be shared with the other outputs of the refining process like diesel, kerosene, jet fuel, heating oil, etc. If we assume that all refinery products require roughly the same amount of processing then 0.55 kWh x 46% works out to 0.25 kWh per US gallon. A UK gallon is 20% larger so adjusting for that we get 0.3 kWh per UK gallon.

Similar calculations based on US government data (which roughly matches UN data on the US) shows similar results.

So where did the "4.5 kWh of electricity" per gallon claim come from?

Similar claims of around 7 kWh of electricity per refined gallon of US gasoline per used in early Nissan marketing materials for the LEAF but were later abandoned. Others have calculated that about 6 kWh of energy is used to refine a gallon of gasoline using US government data.

These numbers likely represent calculations of the kWh of energy, not electricity, used in refining a gallon of gasoline. Just like gasoline is sometimes measured by weight, non-electrical energy is sometimes measured in kWh and this can cause confusion.

The vast majority of energy used in refining gasoline comes directly from fossil fuels -- mostly natural gas and leftover output from refining earlier crude that can't be economically sold to customers such as "still gas".

Here's a page that breaks down the energy input used by the refining process in the US. Although it isn't obvious at first glance, if you calculate the energy value of the various inputs you will find that they total about 20x to 30x kWh larger than the electricity listed there or on the UN site for US electricity usage by refineries:

http://www.eia.gov/dnav/pet/pet_pnp_capfuel_dcu_nus_a.htm" onclick="window.open(this.href);return false;

Since this is an important story and is often misunderstood, I suggest that you find and interview an expert on the gasoline and diesel refining process and then use this to update and republish your episode with better information.

Thanks for all the effort you put into making Fully Charged an excellent forum for promoting plugin vehicles!

 

[LeftieBiker]

Just passing through, but...

Therefore, the energy used in refining needs to be shared with the other outputs of the refining process like diesel, kerosene, jet fuel, heating oil, etc. If we assume that all refinery products require roughly the same amount of processing then 0.55 kWh x 46% works out to 0.25 kWh per US gallon.

Gasoline doesn't require about as much processing as, say, home heating oil or kerosene - it requires substantially more. It is the most complex product of the bunch, and is much more energy intensive to produce, between refining it more and formulating it with additives. 7 KWH may be high, but 0.25 KWH is definitely too low.

 

[JeffN]

Just passing through, but...

Therefore, the energy used in refining needs to be shared with the other outputs of the refining process like diesel, kerosene, jet fuel, heating oil, etc. If we assume that all refinery products require roughly the same amount of processing then 0.55 kWh x 46% works out to 0.25 kWh per US gallon.

Gasoline doesn't require about as much processing as, say, home heating oil or kerosene - it requires substantially more. It is the most complex product of the bunch, and is much more energy intensive to produce, between refining it more and formulating it with additives. 7 KWH may be high, but 0.25 KWH is definitely too low.

True, but even if all the other products put out by refining the crude oil were assigned no grid electricity at all then gasoline would by 0.55 kWh per gallon. Obviously, the other 56% of refinery output needs to be assigned some of the grid electricity. I don't know the exact ratio of energy for refining gasoline vs. kerosene and home heating oil etc. but I'm sure further research can turn up an answer.

In any case, the amount of grid electricity is almost certainly between 0.3 kWh per gallon and 0.55 kWh per gallon and is radically less than 4.5 kWh. Almost all of the energy used in refining is in the form of fossil fuel. You couldn't just put that 4.5 kWh directly into your LEAF instead of refining the gas. You would have to burn it in a generation plant at 35% efficiency or so first.

 

[QueenBee]

Unfortunately this misinformation about the grid electricity used by refineries keeps bouncing around the Internets and recently made its way into a grossly misleading episode of Fully Charged.

Thanks for taking the time to debunk this and provide such a thorough and easily understood explanation. I keep hoping the too good to be true aspect of this would keep it from spreading but unfortunately it just doesn't want to die. There are so many reasons why EVs are great so we don't need flat out fallacies to support them.

 

[Zythryn]

Jeff, I agree the 4-7kWh number I see is for total energy used.
However, regarding the Fully Charged piece, as I recall he was taking an example of a single refinery, not the entire UK. It very well be that refinery got all of its power from the grid for some reason.

However, one example is a terrible way to make a general statement. Unless you are looking for data that impacts an individual that would get all their gasoline from that one refiner.

 

[JeffN]

Jeff, I agree the 4-7kWh number I see is for total energy used.
However, regarding the Fully Charged piece, as I recall he was taking an example of a single refinery, not the entire UK. It very well be that refinery got all of its power from the grid for some reason.

However, one example is a terrible way to make a general statement. Unless you are looking for data that impacts an individual that would get all their gasoline from that one refiner.

Watch it again:

http://youtu.be/BQpX-9OyEr4" onclick="window.open(this.href);return false;

He's talking about the several big refineries in the UK but at one point mentions a single specific refinery that he visited years ago while making a different television program. The amount of electricity he mentions being used is consistent with the UN statistics for the grid electricity used by all refineries in the UK. It seems like a huge number of kilowatt hours but the refineries also produce huge numbers of gallons of gas. When you divide the numbers the amount of grid power for each gallon is about 10 times smaller than the 4.5 kWh per gallon that he mentions and that's ignoring all the other non-gasoline products that come out of refining the crude oil. The real UK refinery grid power use is roughly consistent with the typical electricity used by US refineries.

He also spins that oil company conspiracy about hiding the data after 2005 but when you look online the data is available up to 2010 and more recent data within the last 4 years is available off-line from the UN. The entire episode is a misleading mess that should be taken down and redone with accurate information.

 

[DaveinOlyWA]

Someone asked me whether my EV was actually saving the environment or hurting it. I didn't know, so I found some documents that give me facts to use in a head-to-head calculation. Please see below and let me know if you see any errors in this approach or if you doubt any of my assumptions.

For EV:
http://www.eia.gov/tools/faqs/faq.cfm?id=74&t=11" onclick="window.open(this.href);return false;
Natural gas (a clean fuel) produces 1.22 Lbs CO2 per kWh produced
Sub-bituminous coal (bad stuff) produces 2.16 Lbs CO2 per kWh produced
Average those to 1.69 Lbs CO2 per kWh
My Nissan Leaf gets approximately 4.5 miles per kWh, better in summer, worse in winter
That means 0.3755 Lbs CO2 per mile or 170 grams of CO2 per mile with a Nissan Leaf

For ICE:
http://www.epa.gov/otaq/climate/documents/420f11041.pdf" onclick="window.open(this.href);return false;
Combusting one gallon of gasoline produces 8,887 grams CO2
Assuming 40 miles per gallon, that is 222.2 grams of CO2 per mile with an Economy Car

I'm ignoring electricity transmission losses (15%?) and also ignoring fuel transportation pollution (no idea), blindly assuming that they wash each other out.

So in this comparison, the EV is slightly better for the environment.

What do you think? Are these assumptions valid? Is the data recent enough? Did I slip a decimal point?

Thank you for your comments.

Bob

this is a shortsighted view of the problem and problem it is. it is VERY easy to make the electrical grid much cleaner. it is not easy by any stretch of the imagination to make the gasoline monstrosity significantly cleaner.

hey, you hear that?? another death knell for a coal based electricity plant!

 

[RegGuheert]

it is VERY easy to make the electrical grid much cleaner.

This is Myth #3 in Gail Tverberg's list of the eight most popular energy myths. (Not picking on you, Dave, as I suspect we all (or nearly all) have beliefs which Gail attacks on that list! I tend to believe Myth #7.) In any case, it is an excellent, though-provoking read. We all need to pay close attention to Myth #8!

another death knell for a coal based electricity plant!

I'm all for getting rid of coal-fired electricity plants, but I'm not convinced that converting them all to biofuel is a good idea. Destroying beautiful places like West Virginia to get at coal is a terrible thing but destroying forests is also a bad thing (although likely much more recoverable than mountaintop removal). Specifically, leveling forests in North Carolina to create wood pellets to ship to the UK to burn in the massive Drax power plant seems like a really bad idea to me.

 

[DaveinOlyWA]

it is VERY easy to make the electrical grid much cleaner.

This is Myth #3 in Gail Tverberg's list of the eight most popular energy myths. (Not picking on you, Dave, as I suspect we all (or nearly all) have beliefs which Gail attacks on that list! I tend to believe Myth #7.) In any case, it is an excellent, though-provoking read. We all need to pay close attention to Myth #8!

another death knell for a coal based electricity plant!

I'm all for getting rid of coal-fired electricity plants, but I'm not convinced that converting them all to biofuel is a good idea. Destroying beautiful places like West Virginia to get at coal is a terrible thing but destroying forests is also a bad thing (although likely much more recoverable than mountaintop removal). Specifically, leveling forests in North Carolina to create wood pellets to ship to the UK to burn in the massive Drax power plant seems like a really bad idea to me.

picking on me is fine. I don't post to public forums to agree with anyone anyway. I am here to shake things up. more than enough "yes men" here to fuel just about anyone's egos

I dont think that we have the luxury of "stepping" up our cleanliness anymore so going with gas because its a bit cleaner is not in the cards for me. we have too much to clean up for that and really little time to do it.

and yes, the guy you mention has a point, albeit a weak one. there is no perfect solution but picking on the bad points while ignoring the obvious part of the unlimited nature of solar, wind and the water cycle is more than a bit played out dont you think?

 

[AndyH]

Energy use for a gallon of gasoline was hashed over pretty thoroughly when the forum was a bit younger - there might be some useful nuggets there for the 'rebuttal analysis'...

http://www.mynissanleaf.com/viewtopic.php?f=13&t=820