Net CO2 Emissions Coal vs Heating Oil

Since I first considered coal about 5 years ago, I've often wondered just how much worse CO2 emissions were when everything was netted out. This means calculating the CO2 costs of transporting OIL from Saudi Arabia to the US for purposes of refining into Heating Oil and then burnt for heat. It was always easy to compare tons of CO2 between Coal and Heating Oil for heat, but that small detail of transporting is always omitted. All this is moot, of course, if you believe CO2 emissions have little to do with "climate change" (but let's not go there right now).

Anyway, I took a SWAG at it today. It looks like coal is a better choice if you live near PA on the order of 40% lower net CO2 emissions. Please have a look (excel sheet attached, jpg for those without excel). I'm posting in part to check my logic and math, but also for suggestions on how to improve the message. Thanks!

Is that spreadsheet you made up yourself?

Anthracite is going to have a BTU value of around 24 million to 25 million per ton or equal to 173 or 180 gallons of oil.

Rich, yes, I'm building the spreadsheet myself. One of the sites I referenced had 20MBtu per coal ton, but did not distinguish between coal types. Since you mentioned it I do recall that it was closer to 180 gallons of HO per Anthracite ton. Do you have a source I can reference? Plugging in your numbers the reason for burning anthracite only gets better (2.79 tons of CO2 saved). Thanks for the thoughts.

I'm moving this to the Energy, Coal News and Discussion forum.

No specific source but I just went over this during email conversation with the person responsible for the EIA comparison calculator because they had dropped the BTU content to 22 million BTU per ton. There's reference on that site that quotes a figure of about 25 million per BTU but I think that might be a little above average. The breakers test their coal and it's going to be in the 12,000 BTU/lb. range.

EIA Fuel Comparison Calculator Shenanigans

The BTU for soft coal can be higher or lower, anthracite is pretty stable.

Edit: Just to add it should be noted that Anthracite is going to have a higher CO2/BTU value than anything else including soft coal so if you're getting your figures from soft coal they won't be accurate.

I've been thinking about his and it's interesting topic to pursue however there is some issues and I'm not sure where you would get the data to address them. I haven't looked but I wonder if there isn;t already a life cycle assessment of say one gallon of home heating fuel delivered to a house in the Northeast. If you had that you'd only have to determine what it is for anthracite.

Off the top of my head you'd have to address the following averages for at last the coal if not for both:

• Acquisition values for both (mining, pumping).
• You'd need an average for all points of oil production being imported. Canada for example is the largest source.
• Refinement and processing values for both.
• Distribution values which would be all over the charts depending on area and method of distribution.

Good stuff.

Numbers 13 and 14 on the list. How can CO2 from coal be heavier than that from oil? If extra Oxygen bonded with it, it would beCO3 and not Co2. I think the reference might be in regard to Co which will pick up the extra O atom to become Co2.

Richard

Richard S. wrote:

• You'd need an average for all points of oil production being imported. Canada for example is the largest source.

In addition to Richard's post ...

• Is that over 95% of Canadian oil is from oil sands which are much more energy intensive anddificult to procure the oil from.

This will increas the footprint spread between the two fuels even more.

franco b wrote:Numbers 13 and 14 on the list. How can CO2 from coal be heavier than that from oil? If extra Oxygen bonded with it, it would beCO3 and not Co2. I think the reference might be in regard to Co which will pick up the extra O atom to become Co2.

Richard

I believe it's because coal has a higher carbon/lb ratio than HO. Solid vs. liquid. Pound per pound, there's more BTUs produced from coal and therefore more CO2 .

Because coal is almost pure carbon, there is no shortage of available atoms to pick up a pair of Os. The level of carbon atoms in oil is about 1/3 the volume of the molecule. So there is less available carbon in the oil. Oddly enough, this seems to indicate that oil converted to energy has a higher ratio of CO2 for the amount of total carbon it contains.

CO2 is not really a pollutant, despite what Al and Co. say. It would be interesting to add the NOX and SO #s to this and see how ugly oil really is in comparison.

CO3 is very unstable and very difficult to produce. It behaves much like ozone and would quickly return to CO2 because of that instability.

I'm delighted to see a healthy exchange of ideas on this topic. I've harvested a number of good ideas to improve the spreadsheet. Some of the information will be difficult to attain, and like most things like this, it's a SWAG based on assumptions and available data. I'll need to go off for a few days and compile a better spreadsheet, but I think there's enough of an interest here to push it forward (I've already satisified my own curiosity).

Regarding the chemical comps of oil and coal, it's reported on their respective wikipedia.org pages that petroleum logs sulfur in at .5% to 6%, while anthracite logs about 1%. So the percentage of sulfur and hydrogen emitted per btu from oil is potentially 6x higher than anthracite. Also, I noticed that during the refining process the sulfur gets burned off to create low-sulfur distillates, which I imagine, forms SO2. So there's no free lunch. Low-sulfur diesel just advances the emission of sulfur into the atmosphere to the refinery instead of the consumer. The only question is, how completely is it burned off? Richard, if you have any thoughts on this I'd like to hear them.

Thanks to everyone for the comments.

Well i might be able to obtain some data for how much electric and fuel usage for processing and mining... then again they might not want to release it either unless there was a way to anonymize it.

njbill, I've been thinking about this too. Very hard to account for all the variables, but there's one huge environmental/ CO2 cost with fuel oil that gets overlooked. I don''t think you've included it in your analysis, and my bet is that it dwarfs the transportation costs you are considering. I am referring to the electricity demand in petroleum refining, which is massive. In 2005, US refineries consumed 48.9 Billion KWh, and even in California the biggest industrial consumer of electricity is refining oil.

One of the reasons the environmental implications of this get overlooked is because the great majority of refinery electricity consumed is generated at the refinery from burning petroleum and its products, with only a minority purchased from the grid. No one "sees" how massive the use is because it's (nearly) all internal to the refinery. Yet, such generation via combustion exacts an environmental cost via emissions that I've NEVER seen included in an analysis of environmental consequences of combustion of petroleum products.

In addition to refining electricity consumption, getting it out of the ground in the first place is also energy intensive--one estimate (see below) is that 14 kW are required per barrel of oil, adding $2-3 to the price per barrel. I have no idea whether any anthracite miner has ever done it but it would be easy to do: figure out total energy costs/energy usage per month divided by total tons produced per month. This might allow some (very primitive) comparison of coal vs oil extraction costs.

Here are some links for the above info:
http://www.nationmaster.com/graph/ene_e ... refineries
http://www.need.org/needpdf/infobook_ac ... /ConsI.pdf
http://energy.converanet.com/cvn03/cach ... l+s%3Anasa\.CBOAI&cacheid=ds2-va:p:1001t:7457630919376:d3b03bffd8a5c71e:4a4a0782&scopeid=defLink

franco b wrote:Numbers 13 and 14 on the list. How can CO2 from coal be heavier than that from oil? If extra Oxygen bonded with it, it would beCO3 and not Co2. I think the reference might be in regard to Co which will pick up the extra O atom to become Co2.

Richard

Richard,

The figure that you are questioning, should be viewed as: the TOTAL WEIGHT of Carbon (coal) fuel (2000lbs) + the WEIGHT of Oxygen (combustion)= TOTAL CO2 WEIGHT. (although I am not "proofing" his equation, it could be a reasonable approximation)


Bob


ps:
For the BTU equivalent in oil: Lesser weight of both fuel and total Oxygen for combustion results in lower total CO2

RMA wrote:

franco b wrote:Numbers 13 and 14 on the list. How can CO2 from coal be heavier than that from oil? If extra Oxygen bonded with it, it would beCO3 and not Co2. I think the reference might be in regard to Co which will pick up the extra O atom to become Co2.

Richard

Richard,

The figure that you are questioning, should be viewed as: the TOTAL WEIGHT of Carbon (coal) fuel (2000lbs) + the WEIGHT of Oxygen (combustion)= TOTAL CO2 WEIGHT. (although I am not "proofing" his equation, it could be a reasonable approximation)


Bob


ps:
For the BTU equivalent in oil: Lesser weight of both fuel and total Oxygen for combustion results in lower total CO2

AS I LOOK AT THESE NUMBERS...

LINES 13 & 14 Address CO2 this raises the question of the other GREEN HOUSE GAS...WATER VAPOR!!!

Coal's (carbon) combustion results in primarily CO2 (LINE 13)
Oil's (hydro-carbon) combustion results in CO2 and WATER VAPOR (another green house gas)



Bob

I'll quote the following EIA page, hopefully it clears up the CO2/weight discussion.
http://www.eia.doe.gov/cneaf/coal/quarterly/co2_article/co2.html

"Carbon dioxide (CO2) forms during coal combustion when one atom of carbon (C) unites with two atoms of oxygen (O) from the air. Because the atomic weight of carbon is 12 and that of oxygen is 16, the atomic weight of carbon dioxide is 44. Based on that ratio, and assuming complete combustion, 1 pound of carbon combines with 2.667 pounds of oxygen to produce 3.667 pounds of carbon dioxide. For example, coal with a carbon content of 78 percent and a heating value of 14,000 Btu per pound emits about 204.3 pounds of carbon dioxide per million Btu when completely burned.(5) Complete combustion of 1 short ton (2,000 pounds) of this coal will generate about 5,720 pounds (2.86 short tons) of carbon dioxide."

Hydrogen comprises only 10-14% of petroleum by weight, where carbon comprises 87%. The amount of resultant water vapor I believe is minimal. Coal, by way of comparison, is about 1% hydrogen.

Lastly, I promised a better spreadsheet that takes into account more factors. However, given that 50% of US domestic kwh is produced by coal, and the scarcity of data on the energy required to mine coal and refine petroleum, I've decided to publish the final spreadsheet with some minor tweaks and corrections.

When all is netted out, you can't get over the CO2 cost to ship from Saudia Arabia to the US. Perhaps if there was a closer source of oil, or you assume that HO is derived from domestic petroleum sources, you can get guilty about burning coal if you're CO2 biased.

I'd like someone in the shipping business to validate the supertanker fuel consumption and travel time, but outside of that, there's not much more I can do with the calcs. The data I used came from here http://www.epa.gov/OMS/models/nonrdmdl/c-marine/r00002.pdf. As for me, I've satisifed my curiosity.

Thanks for the input.
Bill