For a minute there I thought I had to get off my couch, when all the while the fact is we don't have to do anything much but keep things afloat for just a few decades more! In fact, we'd best shut up about PO, because if our offspring finds out we knew about it all along, they'll turn and wring our necks come 2036!
Joined: Oct 18, 2004 Posts: 266 Location: San Francisco, CA
Posted: Sat May 05, 2007 12:28 pm Post subject: Re: Why ethanol sucks -- can someone check my math
pstarr wrote:
you must consider cradle-to-grave life cycle analysis when measuring and comparing primary energy sources. This entails an energy accounting and a tally of debits/credits and (for capitalized assets like solar panels, windmills etc.) depreciations.
Thus, the acre will produce corn ethanol year after to but each season it requires chemical inputs (including fertilizer and biocides) and especially energy for planting, cultivating, and harvesting. The grain must be milled, hydrolyzed, fermented, distilled, and cleaned to make ethanol. This cost energy.
Likewise silicon must crystalized at great energy expense to form solar arrays.
The value generated by this study is commonly called EROEI (energy returned on energy input.) It is an up-and-coming discipline that you might want to consider studying when you get to college.
I know about EROEI, I was just looking at it from an abstract point of view.
Also, any solution with renewables must include some kind of DEMAND side management, so that when the renewables aren't producing enough power demand goes down.
For instance, variable metering, and smart appliances so that heaters, air conditioners, stoves, etc., anything that hogs power automatically shut off or reduce power consumption when the price for power goes over $X / KWH.
That, combined with millions of electric cars plugged into the grid 23 hours per day to provide backup power, should allow us to power everything with solar and wind.
Posted: Mon Aug 18, 2008 3:19 pm Post subject: Re: Why ethanol sucks -- can someone check my math
Also note that if everything were powered with solar, wind, water; all we would have to use in fossil fuels to keep the network (grid) running is enough solar panels and wind generators to serve the replacement and growth rates (hopefully minor.)
The replacement rate should be far more tolerable than the mass retrofitting needed to initially get the grid off of petrocarbons and nuclear.
The world will go electric- what's left of it. There would be too many memories and innovators for it not to.
Joined: Apr 08, 2006 Posts: 1239 Location: Somewhere there
Posted: Wed Aug 20, 2008 9:25 pm Post subject: Re: Why ethanol sucks -- can someone check my math
PhebaAndThePilgrim wrote:
Good luck: From Pheba, from the farm:
You can figure at least one pound of synthetic nitrogen fertilizer (think natural gas) for each bushel of corn. Not each acre, each bushel. The maximum corn output on the top land in the U.S. is 200 bushels per acre. That is an amazing figure. Add potash and phosphate to the mix. Also, add fuel for the tractor and combine, etc. Add fuel to transport the corn, process the corn, etc. etc.
Here at our farm we have stopped feeding corn to our cattle. We can no longer afford it.
We are spiralling into a black hole of negative energy in the U.S. because of ethanol.
Ethanol is insane.
Pheba.
You forgot to mention that it makes food scarse and expensive, thus forcing oil-exporters sell more oil, since none of them had learned to feed themselves apparently. They are also happened to be located near countries who have no oil nor food. Burning food makes a ton of sense if you are not to eat it anyway.
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