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RE: Great, even more ethanol BS
By inperfectdarkness on 1/15/2008 10:00:15 AM , Rating: 2
the article was from pop mechanics...referencing alternative fuels(it was about 2 years ago). hydrogen production was listed at 32% efficiency, gasoline at 80% efficiency, ethanol at 112% efficiency. the percentages were based on amount yield vs. amout input.

fossil fuels will always remain inherently semi-efficient. though they have high energy contents--the amount of energy required to extract them is high. bear in mind, most estimates on energy required to extract fossil fuels do NOT accurately map the energy/labor taken to initially drill, pump, mine, and harvest the fuels (much higher than any alternative sources); and instead focus only on the refining process.

that's not even to mention the additional expenditure to scout new places to drill/mine.

anerobic ethanol production from microbes can be installed for a much lower cost--especially seeing as how we already have sewage systems in place for collection of waste. (not to mention landfills, etc). we don't have to collect and ship to a central processing station. we can simply build the processing station at the landfill or sewer plant.

since the "feedstock" will be provided by existing processes, and the process itself is essentially self-sustaining; the energy efficiencies reaped by this method of ethanol production will be much higher than anything else. AND...we'll have additional water supplies for those areas that are stricken with drought.

The OP was correct. While this is a major innovation, we're never going to "solve the energy problem" with waste biomass. It can certainly help reduce the growth in demand somewhat for petroleum, but it's not going to do more than that.

when we've depleted our landfills, and we've used all of the sewage we create--and we STILL haven't curbed our dependence on oil...then i'll believe you. we have way too much garbage, etc for me to agree.

worst case? we have solved the problem of waste materials...and we use the bountiful supply of ethanol in electricity plants; while we buzz around on 400mile electric plug-in cars.

RE: Great, even more ethanol BS
By masher2 (blog) on 1/15/2008 12:28:05 PM , Rating: 2
> "fossil fuels will always remain inherently semi-efficient...the amount of energy required to extract them is high."

Again- I don't know where you're getting this information. Lifting costs for Saudi oil are a few cents/bbl. It's significantly higher for, say, oil from the Gulf of Mexico, but its still a tiny fraction of the energy received. The largest consumer by far is the refining process, particularly if heavy cracking or reforming is done, and even still its nowhere near the amount required to produce ethanol. It's not even on the same order of magnitude.

Seriously, Google is your friend here. Even a few minutes of intelligent browsing should convince you of this.

> "we have way too much garbage, etc for me to agree."

A simple back-of-the-envelope calculation will show you why "garbage" cannot solve our energy problems. I'll start you off. We consume some 20.7 M bbl/oil per day. That's over 125 trillion joules of energy/day.

Now-- using the caloric content of all food produced in the nation, and even assuming this process was 100% efficient and required no energy input, AND we don't even eat any of the food the nation produces-- demonstrate why we cannot possibly fill our needs with garbage (proof left as an exercise to the reader).

RE: Great, even more ethanol BS
By clovell on 1/15/2008 2:59:26 PM , Rating: 2
Masher, why are you only counting food in those calculations? I thought that this process could use a lot more than just food.

RE: Great, even more ethanol BS
By masher2 (blog) on 1/15/2008 3:48:10 PM , Rating: 2
The comment that started this all was that "sewage" (waste food) could solve our energy needs. My statement was simply to prove that incorrect, not to deny there may be other sources for this process.

RE: Great, even more ethanol BS
By clovell on 1/16/2008 12:33:27 PM , Rating: 2
XD - Ah, that makes sense.

RE: Great, even more ethanol BS
By inperfectdarkness on 1/16/2008 2:24:00 PM , Rating: 2
you're not counting other waste.

sewage alone can't fill all of our least not if you're using human waste alone.

however, look at how many hydrocarbons we trash every year. plastic bottle, old cd's, worn tires, etc. we not only have feces to use as feedstock...we have FORMER oil that was processed into various, now-used-up items.

in 1995, 151.9 MILLION tons of trash were disposed of (that's net trash...after excluding recyclables). well over 60% of that contained hydrocarbons (read: feedstock). (metals and glass accounted for a mere 15% of that).

now i'm no energy expert...but wessex water treats 480 MILLION litres of sewage per day.

it's fair to assume we produce, cumulatively, a lot more here in the U.S.

400,000 tons of trash & oh, let's say 1 million liters of sewage--PER DAY...hmmm....

maybe not enough to totally supplant oil...but damn close if it doesn't.

By inperfectdarkness on 1/17/2008 9:00:26 AM , Rating: 2
p.s. subtracting the 15% that's glass and metal, that's:

680 MILLION pounds of trash per day. in just organic materials.

680 M pounds of trash to create the energy in only 20 M barrels of oil.

PLUS the amount of sewage we generate each day.

i'm not seeing what's so impossible here.

