Energy III: Ethanol -- someone's smoking corn-silk
I've been avoiding this because I don't have all that much to say. The bottom line is the same that I have given for hydrogen: ethanol cannot be produced by burning ethanol. At best, we are burning petroleum at a different point of our energy cycle, and getting correspondingly less energy from doing so. We may be producing less particulate pollution, and less carbon monoxide, but that by definition means an ethanol reaction produces more carbon dioxide. To be sure, carbon dioxide is not as toxic as its oxygen-deficient relative, but there is no serious challenge to the conclusion that human activity has raised the level of carbon dioxide in the atmosphere to levels last seen when global temperatures were higher than they are now -- and it's probably as cool as it is now only because particulate smog has deflected sunlight, dropping temperatures an average 1 degree for every 2.5 degrees they are raised by greenhouse gas heat retention (I confess: I saw the Nova episode). For this reason, ethanol is even less realistic than hydrogen.
As I noted on Sage Thrasher's site, we've known for a while that producing ethanol from corn results in a net energy loss. A study by David Pimental puts that energy loss at 41% -- more than 4/10ths of energy used to create ethanol is simply lost. Other studies indicate a loss higher than 65%.
These figures are based on the energy required to grow the corn, as well as to ferment ethanol from it, and as such represent some problems: given that we also eat corn, and assertions by some commentators that usable materials remain after fermentation, some of that energy may be improperly allocated to the fuel generating processes. However, that calls into question how much arable land, fertilizer, waste-water processing, and other costs would be involved producing enough ethanol (from corn, which is much less glucose-rich than Brazil's sugar) to replace the 100 million gallons of gasoline we use each day. If we assume that 36.5 billion gallons of gasoline per year represents 111 T(tera)g (803 kg/cubic meter; .0038 cubic meters/gal), that means about 4,771,000 TJ (teraJoules) per year. That would require 179 Tg of ethanol, or 59.5 billion gallons. Further assuming 406 gallons of ethanol per acre of corn, that would mean 146 million acres. Further assuming 78 million acres under corn, that would mean we would have to cultivate under corn almost twice as many acres as we do now. Even assuming that we could, through improved vehicle efficiency, satisfy demand with only the current 78 million acres, that would mean none of that corn could be used to make popcorn, corn fritters, corn tortillas, or high-fructose corn syrup. And that assumes that we use some other energy source than ethanol to produce that ethanol.
Check my math, if you like. I can see no way that ethanol can replace gasoline in the U.S. Those who propound it as such are clearly smoking corn silk. Or perhaps blowing said smoke to score political points in the Midwest.
So you have an energy source we couldn't even produce in sufficient amounts to run our transportation system, which releases carbon dioxide when produced and more carbon dioxide when combusted in an engine. Hydrogen's better, and you know what I think about hydrogen.
As I noted on Sage Thrasher's site, we've known for a while that producing ethanol from corn results in a net energy loss. A study by David Pimental puts that energy loss at 41% -- more than 4/10ths of energy used to create ethanol is simply lost. Other studies indicate a loss higher than 65%.
These figures are based on the energy required to grow the corn, as well as to ferment ethanol from it, and as such represent some problems: given that we also eat corn, and assertions by some commentators that usable materials remain after fermentation, some of that energy may be improperly allocated to the fuel generating processes. However, that calls into question how much arable land, fertilizer, waste-water processing, and other costs would be involved producing enough ethanol (from corn, which is much less glucose-rich than Brazil's sugar) to replace the 100 million gallons of gasoline we use each day. If we assume that 36.5 billion gallons of gasoline per year represents 111 T(tera)g (803 kg/cubic meter; .0038 cubic meters/gal), that means about 4,771,000 TJ (teraJoules) per year. That would require 179 Tg of ethanol, or 59.5 billion gallons. Further assuming 406 gallons of ethanol per acre of corn, that would mean 146 million acres. Further assuming 78 million acres under corn, that would mean we would have to cultivate under corn almost twice as many acres as we do now. Even assuming that we could, through improved vehicle efficiency, satisfy demand with only the current 78 million acres, that would mean none of that corn could be used to make popcorn, corn fritters, corn tortillas, or high-fructose corn syrup. And that assumes that we use some other energy source than ethanol to produce that ethanol.
Check my math, if you like. I can see no way that ethanol can replace gasoline in the U.S. Those who propound it as such are clearly smoking corn silk. Or perhaps blowing said smoke to score political points in the Midwest.
So you have an energy source we couldn't even produce in sufficient amounts to run our transportation system, which releases carbon dioxide when produced and more carbon dioxide when combusted in an engine. Hydrogen's better, and you know what I think about hydrogen.
posted by heavynettle at 23:17
8 Comments:
What's your take on methanol?
It'll make you blind, then kill you. The only antidote is to drink lots and lots of liquor.
My take on all of the synthesized fuels, from ethanol and methanol to biodiesel, is that they are much more useful for disposing of waste and, gee whiz, getting something useful out of it than creating a solution to our energy issues. Biodiesel is the most useful in that regard, but, of course, the dirtiest of them as well. As for methanol, as with ethanol, I'm sure we can do better things with our forests than turn them into methanol farms -- although wood-shavings et al. from lumber yards, like discarded restaurant grease, can be useful on a small scale at local levels: specially adapted vehicles, home generators, stuff like that.
The problem is that in producing and using these fuels, we release carbon dioxide (more than when we just burn petroleum, in the case of the -ols), which is highly problematic. Hydrocarbons have to become a much smaller part of our fuel source in any case: the shrinking reserves of petroleum just gives us a good excuse.
Save ethanol for beer, man.
I saw a documentary a while back about methane from human and pig waste being generated in rural China. Each house created enough crap to run a single lightbulb all night. I guess in California they are doing something on a commercial level with cow patties.
It seems increasing scarcity of oil is going to be a self-correcting problem over time if the market forces are allowed to function naturally, a big if to be sure.
Yeah, that's what I have to concede about methanol, cooking grease, and biodiesel: incidental use. My solution includes decentralization: getting away from the notion of a central utility providing all electricity. I envision more residential solar and wind, but a restaurant could buy a handy-dandy Mr. Biodiesel and use it to process exhausted cooking oil into a supplemental heating fuel; farms could produce ethanol from waste (or just burn it, or mulch it into fertizlier), lumber yards could produce methanol from waste (or just burn it), etc.
Unfortunately, these above uses aren't much different from every house burning cow manure or firewood: carbon dioxide and particulate pollution from millions of sources -- and why developing countries like India are worse greenhouse gas emitters than developed nations like the U.S. So, again . . . masked costs: those Chinese farmers are making choices based on economics, without considering that, if enough other persons did it, changes in regional temperatures and rainfall could actually damage their crops.
Of course, as I say that, I have to remind myself that methane is a much more potent greenhouse gas than carbon dioxide, so I can't pick on those farmers.
What was I saying?
I should add something, since my solution does not call for an all or nothing energy source: limited use of ethanol can be of use. The thing to remember is that any percentage of our daily gasoline usage to be taken up in ethanol results in a corresponding loss in current acreage for edible corn: a 15/85 ethanol/gasoline ratio requires 21.9 million acres, almost a third of that currently under corn, to be devoted to energy production (not including, of course, the fuel necessary to synthesize the ethanol).
But here I go again. If you assume that petroleum (heating fuel) is used in the synthesize, you wind up using more petroleum (albeit a different product of it) than you're saving by dropping gasoline use by 15%. It's a losing proposition for mass usage.
So I haven't added anything. Ethanol is a will-o-wisp, and only the gullible give any credit to Bush for advocating it.
I can't believe I let this slip! Thank you, Sage Thrasher, for hitting one of the central problems of our energy policy: if the market were allowed to develop naturally, consumers would opt for technologies that were more cost, time, and values-efficient. Removal of royalties for gas and oil extraction, and subsidies of all energy sources, would force the prices of all those sources to move closer to their true costs, allowing a comparison -- and an advantage to the lightly subsidized energy sources (solar and wind, for example). This relates to the point I made in the first installment of this series: that masking costs allow costly energy sources to appear cheap. If we could associate all the costs related to an energy source into the kWh price of that source, the most problematic energy sources would be replaced within a couple of years, as consumers made the rational decision to save themselves money by switching to other sources.
Sigh. Why can't the Democrats and Republicans figure that out? Oh, that's right: they're too busy paying off their supporters or buying new ones. With my fucking money.
Interesting, and somewhat though not entirely relevant, article in this month's Atlantic Monthly about the myth the tax cuts force government to shrink. Besides the obvious--government spending grew under W. and Reagan but shrunk under Bush the First and Clinton the First--the thesis of the piece is that tax cuts that don't happen in lock step with service cuts will actually INCREASE government spending by masking the true cost of government. In short, people don't see a decline in service, but they do see a decline in taxes so they assume (rationally, I suppose) that government services cost less than before--and push for MORE services!
And all the beneficiaries are dead when the bill comes due so no one ever learns, at least the trickle-down, piss-on-you people don't.
Very apt thesis in the current political climate: I heard some Republican federal legislator say with pride that as a Republican, he was born to cut taxes. That disconnect is what, perhaps thankfully, may fracture the party -- but the Democrats aren't offering much else. It's just situational irony that their arguing for fiscal responsibility by rejecting the Medicare drug bill and the tax cuts -- but what would they offer if they had their 'druthers?
Off topic. I tell you: if a sitting Presidant had the stones to tell Americans how much, you know, stuff costs (like "I have charts and graphs, so fuck off"), he could trim the edges of the dedicated entitlement constituencies enough to limit the political liability of vetoing spending bills and sunsetting programs.
Shit, now I'm tired again. Bush sucks. The Republicans suck. The Democrats suck. The whole world just sucks, man.
Except, of course, for me.
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