How much energy does it take to produce a gallon of gasoline?

[roflwaffle]

Originally Posted by NeilBlanchard

Can you confirm/deny/correct these numbers?

Confirm and correct.
Here's the data for the energy used in extraction and refining.

Petroleum refining is the number one consumer of energy in California's manufacturing sector. In 1997, the industry consumed 7,266 million KWh of electricity and 1,061 million Therms of natural gas.

Annually, the oil extraction industry uses 3,846 million KWh of electricity 2,910 million Therms of gas.

For 1997, oil production was 340,362,443 bbls (2nd chart), and oil refining was about 650,000,000 bbls. Plug and chug to get the kWh of electricity and therm of natural gas per gallon of oil. Nat gas baseload electricity production is ~50-55% efficient and transmission is ~97% efficient IIRC.

What I didn't include originally was the process efficiency, which according to Robert is 83%, so increase all the values by that (1/.83). On top of that, the oil industry flares a lot of natural gas so that would increase the usable energy for EVs. Back of the pad indicates this was another ~1kWh/gallon of crude as of 2007. Last but not least there's the fuel needed to run the tankers and tanker trucks (Distribution), which is an unknown AFAIK.

Originally Posted by RobertSmalls

This is an unfair comparison. An "average" person driving an electric midsized sedan or SUV at 75mph with the A/C on would not be getting 125-250Wh/mi. If you wanted a fair comparison, the best we have available would probably be a Prius (or a PHEV converted Insight or Tahoe?) driven in EV mode, versus the same car driven the same speed on gasoline.

The only fair comparison involves the FTP75/LA4/J1634 AFAIK. No one has tested EVs and their production counterparts on something like the US06. Using a converted PHEV as a metric for an EV isn't fair either because hybrids have certain design constraints and aren't exactly optimized to function as pure EVs. One of the few decent comparisons I've found is for the older RAV-4. 235Wh/mile in EV mode, plus charging losses, compared to the gas version at 26mpg over the same drive cycle. That's ~400Wh/mile for the old LA version and probably ~250Wh/mile given current battery tech versus +/-1400Wh/mile for the gasser depending on the engine (1996 version or current, which is likely lower)

Originally Posted by RobertSmalls

If refining took more energy in than it put out, people would stop doing it. But until contradicted by citation of better sources, I'm going to stick with the DoE's numbers, as I mentioned here: 83% efficient.

Everything takes more energy in to it than is put out, but people still do everything. The point is that we can't use crude oil as is, so even if we only get out 83% of the energy in the crude, it's in usable forms.

[NeilBlanchard]

So, they refined 27,300,000,000 gallons with 3,846 million KWh of electricity 2,910 million Therms of gas -- that is 3,846,000,000 kWh and 2,910,000,000 Therms?

And to extract 14,295,222,606 gallons of oil, it took 7,266 million KWh of electricity and 1,061 million Therms of natural gas -- that is 7,266,000,000 kWh and 1,061,000,000 Therms.

By these numbers, extraction takes more energy than refining? I'm not sure why that would be.

[roflwaffle]

Lesse, extraction was ~N gallons of oil, and that took ~7.3 billion kWh of electricity and ~30 billion kWh of natural gas. refining was ~2N so adjusting for the difference in volume for ~N gallons of oil it took ~1.9 billion kWh of electricity and ~45 billion kWh of natural gas. Refining takes more energy per unit of oil because it needs more natural gas while extraction needs more electricity per unit of oil.

[NeilBlanchard]

Right, and we need to apply the same source-to-use carbon totals on the electricity and gas used to produce the oil, as well.

[Christ]

Originally Posted by NeilBlanchard

Right, and we need to apply the same source-to-use carbon totals on the electricity and gas used to produce the oil, as well.

We also need to ensure that, if we're only to be discussing transportation fuels, we only include that percentage of extracted and refined oil which is actually used for transportation, and only that which is used in transportation of a similar nature to the comparison.

IOW - You can't include transportation costs of liquid fuels unless you also note that Electricity energy has fuel transportation costs as well.

I think the part of this whole cycle that bothers me the most is that we use electricity to get oil, then refine the oil and reuse it to get more electricity. Seems kinda stupid, eh?

BTW - The natural gas that gets burned off, at least around here, is considered "dirty fuel" as I understand it. The costs associated with extracting and "cleaning" it are greater than it's fuel value, so they just burn it off.

Wasteful, yes - I'm sure SOMETHING could use that fuel as is.

[NeilBlanchard]

Green Car Congress: Study finds that switch to heavy and synthetic crude oils could double or triple refinery emissions

[Allch Chcar]

Neil the answer is 17% of a gallon.
So 5,695 Watt-Hours.


Using Ethanol to make Ethanol, if only .

[NeilBlanchard]

Steam to extract oil?! Hmmm.

http://www.technologyreview.com/energy/32433/

[fidalgoman]

Along the spirit of the thread, I know you guys care about what we do with the planet. Some extreme and others more practical the bottom line IMO is about stewardship. I don't trust organizations, the largest of which are governments. They have too much invested in status and position to really offer much of a meaningful sacrifice or offer any action that might diminish their position. They "seem" to respond only when it is to their advantage or too painful to hold their position. The whole Idea of selling carbon credits vs. the real solution of reducing carbon emissions into the atmosphere is but one example.

I find it telling that it's OK to trash the planet if you're an underdeveloped economy but not if you're a mature one. Then the developed economies can purchase those same credits. Also the same people who opposed nuclear power in the past now embrace it if it's their side doing it. You can't let your cows piss in the stream but it's OK to dump millions of gallons of effluent into the bay and rivers every day. Way too subjective and self serving for my taste.

In the end I guess it's about balance. Ecosystems can handle a certain amount of stress as long as it doesn't get to be too much. It does take energy to refine and transport energy, that's a given. IMHO it's defining the line about how much is too much. Good or bad, we as a society will determine where that line is. If it were up to me, I'd avoid all the political issues of energy dependence with hostile entities. For those who can acquire it LNG seems to be a plentiful lower polluting energy source than oil. There are even ways to cleanly extract energy from coal but that's such a hot potato I don't care to go there.

Electricity as delivered today is a secondary refined energy source. It's production has consequences. When an affordable and efficient way to store and deliver it is developed I think the only question left for most of us will be about clean generator plants.

[NeilBlanchard]

Hmmm.


(click on image for link)

Seems to me that almost 75% of petroleum energy used for transportation is wasted; compared to ~68.4% wasted in electricity.