From:
http://www.sciam.com/article.cfm?id=grass-makes-better-ethanol-than-corn
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But yields from a grass that only needs to be planted once would deliver an average of 13.1 megajoules of energy as ethanol for every megajoule of petroleum consumed—in the form of nitrogen fertilizers or diesel for tractors—growing them.
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That represents a 5 to 1 ratio
http://www.sciam.com/article.cfm?id=grass-makes-better-ethanol-than-corn
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But yields from a grass that only needs to be planted once would deliver an average of 13.1 megajoules of energy as ethanol for every megajoule of petroleum consumed—in the form of nitrogen fertilizers or diesel for tractors—growing them.
----
That represents a 5 to 1 ratio