Reply #1: This study assumes that E85 will replace *all* US gasoline by 2020 - this is not possible

[jpak]

If the *entire* US corn crop was devoted to ethanol production, it could only satisfy 12% of current gasoline demand. And even with cellulosic ethanol added to the mix, ethanol cannot replace petroleum for transportation fuel.

Other researchers have criticized the assumptions and conclusions of the study...

http://news.yahoo.com/s/ap/20070418/ap_on_he_me/ethanol_health_risks

<snip>

Jacobson's study troubles some environmentalists, even those who work with him. Roland Hwang of the Natural Resources Defense Council, said that ethanol, which cuts one of the key ingredients of smog and produces fewer greenhouse gases, is an important part of reducing all kinds of air pollution.

Jacobson's conclusion "is a provocative concept that is not workable," said Hwang, an engineer who used to work for California's state pollution control agency. "There's nothing in here that means we should throw away ethanol."

<snip>

While praising Jacobson as one of the top atmospheric chemists in the nation, Hwang said he had problems with some of Jacobson's assumptions, such as an entire switch to ethanol by 2020. Also, he said that the ozone difference that Jacobson finds is so small that it may be in the margin of error of calculations.

Jacobson is also ignoring that ethanol — especially the kind made from cellulose, like switchgrass — reduces greenhouse gases, which cause global warming. And global warming will increase smog and smog-related deaths, an international scientific panel just found this month, Hwang said.

<end snip>

Peak oil and the subsequent reduction in gasoline consumption will more than offset any increase in smog and smog precusor emissions resulting from use of ethanol...