Machine Design
Leland Teschler's Editorial: What’s hot? Not ethanol

Leland Teschler's Editorial: What’s hot? Not ethanol

This special issue looks at some of the technologies and industrial themes that are eliciting a lot of interest in the technical community.

But perhaps more interesting than some of the “hot” technologies we review is what you won’t find here: any discussion of ethanol.

January’s North American International Auto Show could well have conveyed the idea that ethanol-based fuel would have been a hot topic this year. Amongst much hoopla, carmakers introduced vehicle after vehicle that could run on E85. Even Ferrari showed off an E85-mobile.

Veteran automotive analysts were unimpressed by this onslaught of E85 exuberance. They knew the real reason Detroit was so keen on ethanol: By producing flex-fuel vehicles, automakers can artificially boost the fuelefficiency numbers they must meet under Corporate Average Fuel Economy standards. That’s because for CAFE, the federal government counts only the amount of gasoline a vehicle consumes getting from point A to B and ignores any ethanol it burns on the trip. A flex-fuel SUV, for example, might get city mileage of about 14 mpg on pure gasoline. But for purposes of CAFE, it is assumed to be running on E85. So on paper the SUV gets about 29 mpg of gasoline in the city.

Of course, most such behemoths will rarely pull up to an E85 pump. So the 29-mpg rating is more myth than reality.

And odds are Las Vegas will become a city of teetotalers before today’s ethanol processes will replace a significant amount of petroleum-based fuels. The basic problem is a lack of heat energy in the feedstock. Crude oil contains about 18,400 Btu/lb; coal, 10,400 Btu/lb. But corn comes in at 7,000 Btu/lb. Switchgrass, billed as the next great hope for ethanol feedstock, has only 6,400 Btu/lb.

The low heat energy of switchgrass means no matter how efficient the refining process, mind-boggling amounts of the stuff are necessary to produce meaningful quantities of ethanol. To see this in real terms, consider an informal exercise cited by energy journalist Robert Bryce. Based on U.S. DOE estimates, a plant able to produce 80 million gallons of ethanol annually would need to take in 1 million tons of corn stubble. That much stubble would take up 67,000 semitrailers. Put another way, that is 187 semitruckloads a day. The plant’s annual output of ethanol would be the equivalent of 53 million gallons of gasoline, or just 0.04% of the U.S. annual gasoline consumption.

But what about biodiesel refined from algae? It’s not clear algae-based biofuel is economically practical. As with switchgrass, you need a lot of pond scum to get much fuel. Researchers at the University of New Hampshire estimate it would take between 9.5 and 28.5 million acres of land, depending on your assumptions, to produce enough algae for U.S. transportation fuel needs. Raising algae in bioreactors is another option, but the cost for meaningful outputs quickly gets into the eyes-glaze-over range.

The best that can be said is that the jury is still out on whether you’ll see algae biofuels in a future “hot” issue.

But enough about that. Readers of our print and digital editions will probably notice Machine Design has a new look. We’ve updated our graphics and introduced a few new features aimed at forging a closer link between the print magazine and It’s all in the interest of better serving our readers.

— Leland Teschler, Editor

Copyright 2008 Penton Media Inc. All rights reserved.

TAGS: Energy Archive
Hide comments


  • Allowed HTML tags: <em> <strong> <blockquote> <br> <p>

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.