Bio-Fuels Have Been a Dangerous Diversion

A little research I have been meaning to do. The answers surprised me:

Best biofuel conversions (Ethanol gallons / acre):
Switchgrass = 1500 (optimum conditions / current record yield)
Sugarcane = 665
Corn 400

Ethanol Energy Density = 24 MegaJoules per liter (MJ/l)

1 Watt-hour (W-h) = 3600 Joules (J)

1 acre = 4046 square meters (m2)

In the south, the average hourly 200 W-h / m2 accounting for seasons, clouds and night.

Skipping all the fun math:

Record switchgrass crop will yield in one year: 136.275 GigaJoules (GJ)

Using bleeding-edge technology (Spectrolab) @ 36% efficiency, photovoltaics will yield in one year (in GA): 9,186 GJ/acre
El-cheapo, 10 year old technology @ 18%: 4,593 GJ/acre

So, with today's technology, pholotovoltaics provide 34 - 68 TIMES more energy per acre than the most efficient, record crop of bio-fuel producing plant.

IN GEORGIA!
(N.B. This analysis does not account for any energy INPUT to crop fuel sources)

Accounting for the efficiency of ethanol engines (35% is very generous) vs. electric motors (80 percent transmission, and 80 percent efficient = 64%), the miles per acre is even more exaggerated, with photovoltaics gaining 61 to 120 TIMES more output per acre!

What does this mean? Put photovoltaics in the field for 2 weeks, and you get the same energy as a crop grown in that field for a year. OR, put 2% of crop land into photovoltaics, and get the same yield as 100% in biofuel crops.

NOW. Take that to the desert, and its even more impressive AND, you can put that Georgia land back into FOOD production.

Main source = Auto Blog Green
Others = American Energy Independence
alt.solar.photovoltaic


Contrarian source (confirms data) = socialissues.wiseto.com