This thread is a derivative of beatle’s http://boards.straightdope.com/sdmb/showthread.php?postid=759352
which I sort of knocked off course without really meaning to. I’ve decided to return the above thread to it’s original purpose and spin off the tangent to here. My questions are:
Are there any good sources contrasting the various petroleum suppliers by fraction? I mean, our dependence on foreign “oil” has been noted, and sometimes propane and natural gas are cited as alternatives. Oil is in quotes because I don’t know exactly what people are including when they use that term. Given that propane and natural gas are petroleum fractions, I guess that raises the question: how much less dependent are we on foreign sources of the lighter petroleum fractions (ethane, propane, etc.), vis a vis the heavier fractions (heptanes, isooctanes, diesel, etc.)?
Another way to put this question is, are propane and natural gas good strategic alternatives to gasoline because we have more propane and NG, or just because we can withstand the inevitable increases in NG and propane prices that would come with automobile conversions? After all, propane prices are hardly as key to the U.S. economy as gasoline and diesel prices; NG is probably somewhere in between. (I emphasize “strategic” to set strategic issues apart from environmental issues - propane and NG have different emissions data than gasoline, but that’s not what I’m talking about.)
Are U.S. petroleum sources richer in NG and propane than foreign petroleum sources?
Non-petroleum sources of NG have been suggested. Are these hypothetical, or are non- “oil field” sources currently in use? Do similar sources existed for propane?
If I’m still not making myself clear, my final version of the question is as follows: how different is a North American (yankee/Canadian/Mexican) oil field in terms of what fractions it produces, than an overseas oil field?
Try the Energy Information Administration site. It’s big and there’s lots of info. They treat Natural Gas and Petroleum separately. In 1999 we imported 16% of the NG we used, most of it from Canada (if more people switch to it in the NE, heating oil concerns will lessen).
I hope this doesn’t count as a cross-post; it was part of my most recent reply to you over in GD.
Most natural gas is not made from petroleum. It exists in gaseous form in nature (hence the name), underground, usually in porous rock structures thousands of feet below the surface. It is usually contained beneath an impermeable layer of rock, which is why it doesn’t all escape to the atmosphere. It is often found in association with coal or petroleum deposits. There are natural gas wells designed solely to tap this resource. I should know because when I lived in W.Va. there were at least a dozen natural gas wells within a one-mile radius of my house.
Natural gas is mostly methane, but the composition varies. There can be significant amounds of ethane, propane, butane, benzene, carbon dioxide, water vapor, hydrogen sulfide, and carbon monoxide.
If natural gas is mostly methane, don’t cows produce a crapload (pun intended) of it? Can’t we somehow find a way to make use of that waste, thereby making NG a slightly less unrenewable resource?
We could harvest it, but last I heard, the conclusion was that it’d be more trouble than it’s worth. It’s a lot easier to attach a pipeline and a tank to the ground than it is to attach it to a cow.
Yes, cattle belch lots of methane, and, as Chronos said, it would be difficult to get much of it back from them. In theory, you could house all your cattle in an airtight building and refine methane from the vent returns, but I doubt that would be cost effective. (A side note - this isn’t “cow flatulence” despite what some lazy reporters might say; methane is generated in the creature’s stomach and is belched by the animal. It is a large percentage of the methane produced by agriculture, industry, and all other human sources.)
I wouldn’t be surprised if, at some point in the future, it were cost-effective to get methane from biomass. That is, discarded corn husks and stuff, which often decompose in piles which don’t admit oxygen. Oxygen-free decomposition results in anaerobic respiration, which produces methane. So, assuming there is any effort to keep solid waste from just sitting on the landscape, a contained environment could yield natural gas. The contained environment could even just be a landfill; methane could be “mined” from certain landfills. It won’t be a big source of NG any time soon, but any gas collected off landfills (or biomass heaps or whatever) is less of it going into the atmosphere increasing global warming potential, so that’s another plus.
The Alexandria, VA, waste treatment plant “generates” lots of methane and/or some other burnable gas. They just pipe it away from the main building and burn it off. You can see it from the I-95/495 part of the Beltway.
True for cows, perhaps, but there is methane harvesting going on out there. There was an article in the paper just today…one local suburb is looking into a system whereby methane from decomposing trash at the landfill would be captured and used to run generators, the electricity from which would be sold to the power company. It implied that this is already going on in other locales…
