Gasoline, electricity, and the energy to move transportation systems

By David Herron

According to a popular factoid, 6 kiloWatt-hours of electricity is used to refine a gallon of gasoline.  Because EV's drive about as far on 6 kWh as gas cars drive on a gallon of gasoline, a big question pops into mind about the global allocation of resources.  Electricity could be used directly to drive cars, rather than being used to make the gasoline that's used to drive cars.  Even that isn't the whole story because electricity is the tip of the iceberg of total resources consumed by the fossil fuel industry.

How does this "6 kiloWatt-Hours per gallon of gasoline" idea work? The research notes and the video below have some details. The basic idea to divide the gallons of gasoline produced from a refinery by the electricity consumed to do so. That gives you the kiloWatt-hours per gallon of gasoline from that refinery.

percent gasoline = gallons gasoline/gallons crude oil
kWh/gallon = (kiloWatt-hours consumption / gallons crude oil) * percent gasoline

OR

kWh/gallon = kiloWatt-hours consumed / gallons gasoline refined

On the surface the claim feels valid - those refineries are huge and must be consuming a lot of energy. However there are a couple problems. One is we can no longer get the necessary data, because it's not being reported. Another is that refineries produce more than just gasoline, making the equation a little bit more complex than just outlined.

Also, there's a question over just how accurate these figures are. For example, a large amount of the "energy" used at the refinery is not electricity, but from burning parts of the oil to produce energy to use in the refining process. And, finally, focusing just on the electricity consumption misses the big picture of all the rest of the resource consumption involved in producing fossil fuels.

Taking the 6 kiloWatt-hours figure on faith for the moment, let's do a few numbers.

EPA's estimate of average fuel efficienty, gasoline cars: 24 miles/gallon
Typical electric car efficiency: 300 Watt-hours/mile
Average EV distance on 6 kWh: 6000 watt-hours/mile / 300 Watt-hours/mile = 20 miles

WTF? I'd much rather, if this is accurate, have that electricity go directly to cars rather than engage in the whole toxic mess of crude oil extraction, refining into gasoline, etc.

It's real tempting to say that we could be driving electric cars off the electricity that's currently used to refine gasoline. But if that's not an accurate statement, we just look like fools. We had better be clear whether this idea is accurate, or not. We have to understand what this means.

Reviewing the known calculations of kiloWatt-hours per gallon of gasoline

No less a person than Tesla Motors CEO Elon Musk likes to say "You have enough electricity to power all the cars in the country if you stop refining gasoline. You take an average of 5 kilowatt hours to refine one gallon of gasoline, something like the Model S can go 20 miles on 5 kilowatt hours." If Elon said it then it must be true, right? He's surely got a staff of fact checkers, right?

The 6 kiloWatt-hour per gallon of gasoline figure comes from Peder Nordby (see Surprise: Gas cars use more electricity than EVs) repeating figures he'd written for his blog about MiniE ownership.  His estimate is based on the overall efficiency of oil refineries (about 85%), a figure from Argonne National Laboratory, and some other conversion factors, in which he deduces that 21,000 BTU's of the 132,000 BTU's in crude oil are spent on electricity for the refining process. That then equates to 6 kiloWatt-hours of electricity.

A video by Robert Llewellyn (below) does some other calculations, based on reported electricity consumption at some set of refineries and their gasoline output, to come up with a figure closer to 4 kWh per gallon of gasoline. Another person came up with a 12 kWh per gallon of gasoline figure. Yet another person came up with a result of less than 100 Watt-Hours per gallon of gasoline.

Earlier I said not all the "energy" used in the refining process is electricity. According to an EPA EnergyStar report on oil refineries, in 2005 many refineries were very inefficient, and that in any case only 15% of refinery "energy" consumption is electricity. That means, if it's 6 kiloWatt-hours per gallon of "energy" that it's actually 0.9 kiloWatt-hours of electricity per gallon of gasoline.

(Doesn't it blow your mind to ponder an Energy Star rating for an oil refinery? But, indeed, that paper gives recommendations for improving oil refinery efficiency. Is one possible result Energy Star stickers for refineries?)

The same paper also said that in 2001, refineries used 47 teraWatt-hours of electricity to refine 5.3 billion barrels of oil into various products. There's 42 gallons of refined products from each barrel of crude oil. After some calculations, we end up with 0.2 kiloWatt-hours per gallon of gasoline.

Towards the bottom of this page is a chart reproduced from an EIA website showing oil refinery energy consumption from a range of resources.  It's clear that oil refineries consume prodigious quantities of energy, the vast majority of which is natural gas and various other fossil fuel resources.  If nothing else, oil refineries produce a large range of crude oil distillates, not all of which are marketable, and which the refinery can burn on-the-spot to produce heat or electricity.  All of which gives us a screaming question to ponder --- what if those resources were instead allocated to producing refined silicon to make solar panels?  Or wind turbines?  Or battery packs?

According to Wikipedia, quoting an Alberta Government fact sheet, 280-350 kiloWatt-hours of electricity is required to extract a barrel of bitumen from the tar sands and upgrade it to synthetic crude oil.  (See Oil Sands @ Wikipedia) That is, the tar sands are what they sound like, thick viscuous stuff, vaguely resembling oil, that's mixed with sand. Just to prepare this stuff for shipment to a refinery, they have to heat the bitumen until it melts and mix it with diluting agents. This is extremely heat intensive, requiring a lot of energy, and occurs way before the oil refinery step of the process.

The toxic dirty lifecycle of gasoline production and consumption involves a witches brew of toxic chemicals, and a tremendous amount of energy and resources to accomplish.

This video features Robert Llewellyn, aka Kryten, explaining the "electricity to refine gasoline" story, giving a few clues suggesting the "6 kiloWatt-hours" figure might be close to the truth.

Volts for Oil | Fully Charged

Source: YouTube

The big picture - wide variety of resource usage, at a huge globe-spanning scale

I'm feeling unsatisfied by these figures. The numbers are fairly close together, sort of, but the methods used don't strike me as being very comprehensive. On the other hand, we're all hobbled by incomplete data about oil refinery operations. Until or unless there's better transparency on oil refinery operations we're not going to have a good understanding.

The other reason to feel unsatisfied is that this focus on electricity consumption per gallon of gasoline completely misses the complete picture. Refining crude oil takes not only huge quantities of electricity, but much more. There's a whole system of crude oil extraction, shipment, and refining each with its own huge globe-spanning infrastructure.

Those huge refineries don't run themselves for free. They require large amounts of energy and other resources.  Towards the bottom of this page is a chart from the US Energy Information Administration (EIA) detailing that resource consumption.

One phrase to think of is "embodied energy", or the sum of all the energy used to create a product.

For crude oil, doesn't the "sum of all energy" consumed in refining it into gasoline and other products much more than the electricity consumption at the refinery? It is, and we go over the refining process below.

What we're really talking about is an investment (resource consumption) and a benefit from that investment (the gasoline, and other crude oil products). The benefit, each gallon of gasoline contains 115,000 BTU's of energy, and the other oil products, is pretty significant and is used for a huge variety of purposes. What's the total energy and resource investment (consumption) to create gasoline and other oil products? Are those resources best used to create gasoline, or can they be put to better uses?

Such as the energy (electricity) to drive electric cars.

Resources involved in converting crude oil to gasoline (and other oil byproducts)

The extensive, globe-spanning, system of extracting crude oil from various places, shipping it to oil refineries producing the many different crude oil products, is mind-boggling in scale. Roughly speaking the process is as follows:

The following comes from "Oil to Car" by Cal. Energy Commission

Extraction: Oil companies extract various hydrocarbon resources from around the world. The old model of drilling a hole into the ground and up comes a bubblin' crude oil (black gold, texas tea) is quickly approaching extinction as the easy oil fields are aging rapidly. Increasingly the techniques used require huge amounts of energy, machinery and other resources, to extract substandard stuff vaguely resembling crude oil. For such "oil", difficult transformations are required just to produce shippable crude oil. For example, tar sands oil is basically strip-mined tar mixed with sand, as the name implies, that has to be liquified and cleaned for transportation. At a huge cost.

Transportation to Refineries: Oil companies prefer to use steel pipelines or cargo ships to carry crude oil. But, increasingly they are shipping crude oil by train. Some of these trains blow up because of derailments, and that the rail cars being used are unsafe for shipping oil. Some even call these trains "bomb trains".

Refining: Crude oil refineries are gigantic chemical plants extracting various components from crude oil. Gasoline is only 51% of the product from refineries, the rest are items like "Asphalt & Road Oil" or "Residual Fuel Oil" or "Coke" (not the drink) or "Jet Fuel" or "Diesel". Gasoline (51%), Diesel (15%) and Jet Fuel (12%) are the big three products. The processes apply heat and various chemicals, causing crude oil to "distill" meaning to evaporate and condense. The machinery involved is huge, and sometimes explodes.

Distribution: More transportation from the refinery, usually through pipelines, to an array of wholesalers and other intermediaries. They'll blend it with other products like ethanol, eventually landing the gasoline in fueling stations at gas stations or elsewhere.

Here's a couple images from our "friends" at ExxonMobile, "A simple guide to oil refining", showing a schematic of a typical oil refinery. The purpose for going over all this is to reiterate the extensive amount of machinery and resources going into the oil refining business.

Are you impressed yet with what's involved?

Macro-economics - the study of the whole economy

The "economy as a whole" is expending a lot of resources into extracting crude oil, and producing various products, the majority of which are fuels for airplanes, trucks, trains, cars, motorcycles, boats, and more. It's clear the system involved is huge, spanning the whole planet, touching into every country and every city. The question at the top is whether the resources we just outlined are being put to their best use.

Put another way, the tremendous amount of minerals, machines, transportation infrastructure, chemical knowledge, human capital, and other resources are being spent on the project of extracting, refining and transporting crude oil and its products. Is it ever so possible that those resources could be better applied to other purposes?

Directing global resources to renewable energy rather than fossil fuel production

What we're talking about is leaving the oil in the ground, and spending the resources dedicated to extracting, shipping and refining crude oil on other purposes. Like, what? That's the big question.

It's not a result that will be achieved overnight by waving a magic wand. Instead it'll take tens of years just to make a significant change. There are many industries to remake, minds to change, a rethinking of what's "normal", and even new technologies to develop.

A precursor question is "why" make the change. The concept of "normal" is that fossil fuels powers our cars and trucks and motorcycles. Given the tendency to not change, to keep on with "business as usual", what's the impetus?

Environmental problems, climate change, the resource wars we're already fighting, and more - those are the result of this belief to use fossil fuels above anything else. These, and related issues, are the crises we need to be solving. Such as, by decreasing fossil fuel dependency.

Think of the immense potential for positive change by switching the resources we just outlined from fossil fuels to renewable energy systems. Engineers are inventive. If tasked with phasing out crude oil products in favor of electric transportation, they'll find ways to reassign resources to electricity production.

It is clear from the material above that the "6 kilowatt hours to refine a gallon of gasoline" isn't the whole story. It's obvious there are gobs and gobs of various resources of all kinds devoted to gasoline production. It's not just electricity that's being consumed, it's steel, and chemicals, and people-time, and on and on and on.

Summary

The idea that "6 kilowatt-hours of electricity is consumed per gallon of electricity" sure seems plausible, especially given the huge amount of all kinds of resources consumed. Whether or not it's an accurate figure for electricity consumption at the refinery is not entirely important. Instead, understanding the bigger picture is important because there is a tremendous expenditure of resources on a global scale, as well as the global environmental impact, just to keep the fossil fuel game going.

Human society is putting gobs and gobs of resources into gasoline production. That stuff represents potential which could flower in a different direction, serving other purposes. Instead of the toxic mess we're suffering thanks to the fossil fuel industry, couldn't we have nice clean renewable energy systems everywhere?

The idea Elon Musk tells us, that there will be no problem supplying electricity to electric cars if only we stop refining oil into gasoline, is tantalizing. But doesn't focusing on "electricity consumed to refine crude oil" make us miss the big picture? Shouldn't we instead focus on the enourmous cost our society is paying?


Research notes

The following is research notes I wrote, maybe in 2012, when I first heard this claim and was hoping to verify it. Unfortunately the evidence I found wasn't concrete bullet-proof validation. Instead, estimates are all over the place from negligible energy/electricity per gallon to as much as 12 kiloWatt-hours. The video above claims it's about 4.5 kiloWatt-hours per gallon, and says that in England statistics had been reported until 2005.

6 kilowatt hours to refine a gallon of gasoline

This is based on an email received from the Dept of Energy published on gatewayev.org. (see http://gatewayev.org/how-much-electricity-is-used-refine-a-gallon-of-gasoline) An article on SolarChargeDriving.com by Peder Nordby used the same argument listed below. (see Surprise: Gas cars use more electricity than EVs) It should be noted that refining one barrel of oil yields gasoline in addition to other products. Thus the energy discussed below is amortized over multiple products, not just the gasoline. Even so, in terms of energy equivalencies, the following estimation is valid.

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% [1. Wang, M. (2008), "Estimation of Energy Efficiencies of U.S. Petroleum Refineries," Center for Transportation Research, Argonne National Laboratory], and Oak Ridge National Lab reports that the net energy content of oil is approximately 132,000 Btu per gallon [1. Davis, S., Susan W. Diegel, and Robert G. Boundy (2009), Transportation Energy Data Book, edition 28, National Transportation Research Center, Oak Ridge National Laboratory].

It is commonly known that a barrel of crude oil generate approximately 45 gallons of refined product (refer to NAS, 2009, Hidden Costs of Energy: Unpriced Consequences of Energy Production and Use, The National Academies Press, 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:

12 kilowatt hours plus other energy inputs

Darrel (EVNUT) http://evnut.com/gasoline_oil.htm

Shows a picture from Nissan's tour of the Nissan LEAF where Nissan claims it takes 7 kilowatt-hours to refine a gallon of gasoline. Nissan says that same 7.5 KWH can drive the LEAF 30 miles.

Darrell provides this estimate

To extract one gallon of gasoline (or equivalent distillate): 9.66 kWh (maybe not all in the form of electricity*) To refine that gallon: 2.73 kWh additional energy (maybe not all in the form of electricity*) Total: 12.39 kWh per gallon.

Roughly one-third of the energy content of a gallon of gasoline produced from California wells is input from natural gas. Less than 2/3's is net energy (probably a lot less!).

And this

And still more from Gassavers.com poster omgwtfbyobbq :

-CA extracts ~300 million bpy (second table), and in order to do this needs about 3,846 million KWh of electricity 2,910 million Therms of gas.

-CA refines ~15 billion gallons of gasoline per year, and this requires roughly 7,266 million KWh of electricity and 1,061 million Therms of natural gas.

Negligable energy cost to refine crude oil into gasoline

This argument comes from http://www.mynissanleaf.com/viewtopic.php?f=13&t=5046

In 2005, US refineries processed 6,250,625,000 barrels of crude oil, and 48% of the output was gasoline, per http://www.npra.org/ourIndustry/refineryFacts/?fa=refineryStatistics They used 48,891,000,000 kWh of electricity to do so http://www.nationmaster.com/graph/ene_ele_con_by_pet_ref-energy-electricity-consumption-petroleum-refineries resulting in 89.4 Wh electricity consumed for every gallon of refined gasoline produced.

48891000000 / 6250625000 = 7.822 kWh/bbl crude oil
42 gallons/bbl -> 7.822/42 = 186 Wh/gal crude oil
186 * 48% = 89.4 Wh/gallon refined gasoline

The chemical energy in one gallon of regular unleaded gasoline is 33.44 kWh. http://en.wikipedia.org/wiki/Gasoline_gallon_equivalent

So, in spite of the mind-boggling amount of electricity consumed by refineries, it only takes away about 0.27% of the gasoline's potential.

But, wait, that electricity isn't the entire fuel consumption in a refinery

The same forum thread containing the "89.4 wh/gallon" figure contained this comment http://www.mynissanleaf.com/viewtopic.php?p=118182&sid=008b9fc100ed149807286f63310b419c#p118182

Referring to http://theev.biz/ev-info/us-oil-refineries-offer-evs-1988-trips-to-the-sun/

The U.S. Energy Information Administration figures released on 24th of June, 2011 that U.S. Oil Refineries consumed/purchased 46,227 million Kilowatthours from electric companies in 2010. That figure easily makes the oil refineries in places like California the electric companies largest industrial customer, which also creates an interesting business relationship dynamic as the oil companies also provide fuel to many of the same electric companies. According to Kenneth Burridge (Editor-in-Chief of EV.com) "The EIA data confirms that quite a bit of the USA's oil consumption, pollution and carbon emissions could be eliminated just by diverting electricity from the oil refineries directly to the garages of drivers willing to commute to work using any type of electric vehicle". He goes on the say "the electric bill of a refinery is only a fraction of the fuel they consume and all costs are eventually passed along to the consumer with every gallon of fuel they purchase. Oil refineries are basically middlemen that EV owners don't need". In addition the oil refinery also uses a large amount of: natural gas, coal, petroleum coke, and millions of pounds of water/steam to produce gasoline and diesel fuel all of which would be not necessary if ICE's could use electricity directly like EVs.

As was said above, oil refineries use many more resources than just electricity.

In If you stop refining oil, how many EVs could you fuel with the saved electricity? it's noted that many refineries run their machines using natural gas or else by burning the "less marketable" portions of Crude Oil.   In other words, while oil refineries obviously consume prodigious amounts of energy, that may not all be electricity bought from the a utility company.

At https://www.eia.gov/dnav/pet/pet_pnp_capfuel_dcu_nus_a.htm we see this chart of energy consumption at refineries:

This shows the vast majority is either natural gas or "Still Gas" and other byproducts of fossil fuel production.   This chart gives us some numbers to ponder demonstrating the prodigious extent of energy consumption to produce gasoline.

Question the macro-economics -- what if all that energy resource was put into refining silicon, and producing solar panels?  We could bootstrap an industry of clean energy production by a few years of consuming this sort of fuel, until there's enough clean energy production to power the factories that produce silicon and solar panels and everything else.

comments powered by Disqus