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Switchgrass |
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amount |
units |
comments |
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18 |
Gj/tonne |
claim(1) |
|
* |
1,000,000,000 |
Giga |
conversion |
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/ |
3,600 |
j/wh |
conversion |
|
= |
5,000,000 |
wh/tonne |
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/ |
1,000 |
kwh/wh |
conversion |
|
* |
10 |
tonne/ha |
claim (1) (2) |
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= |
50,000 |
kwh/ha/yr |
net energy captured by switchgrass |
|
* |
3,413 |
btu/kwh |
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/ |
5,800,000 |
btu/barrel |
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= |
29 |
barrels
equivalent/ha |
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Compare |
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est. |
4.00 |
kwh/m2/day |
approximate sunlight to ground |
|
* |
10,000 |
m2/ha |
conversion |
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* |
365 |
days/yr |
conversion |
|
= |
14,600,000 |
kwh/ha/yr |
total sunlight |
|
* |
0.33% |
|
24 hr efficiency of photosynthesis |
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= |
48,180 |
kwh/ha/yr |
net energy captured by photosynthesis |
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4% |
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difference |
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Sanity Check |
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5,000,000 |
wh/tonne |
see
above |
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/ |
3.413 |
btu/wh |
conversion |
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= |
17,065,000 |
btu/tonne |
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1,000 |
kg/tonne |
conversion |
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17,065 |
btu/kg |
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2.2 |
lb/kg |
conversion |
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7,757 |
btu/lb |
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est. |
8,000 |
btu/lb |
approximate energy content of wood |
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-3% |
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difference |
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Potential using all cultivated land |
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In terawatts |
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est. |
150,000,000 |
hectares |
Cultivated Land USA |
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* |
50,000 |
kwh/ha/yr |
net energy captured by switchgrass |
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/ |
1,000,000,000 |
twh/kwh |
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= |
7,500 |
twh/yr |
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/ |
8,760 |
hrs/year |
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= |
0.86 |
tw
equivalent |
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In barrels of oil
equivalent |
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est. |
150,000,000 |
hectares |
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* |
29 |
barrels equivalent/ha |
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/ |
1,000,000,000 |
barrels/billion barrels |
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= |
4.41 |
billion barrels equivalent |
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1 |
McLaughlin,
S., J. Bouton, D. Bransby, B. Conger, W. Ocumpaugh, D. Parrish, C.
Taliaferro, K. Vogel, and S. Wullschleger. 1999. Developing switchgrass as a
bioenergy crop. p. 282–299. In: J. Janick (ed.), Perspectives on new crops and new uses.
ASHS Press, Alexandria, VA. |
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2 |
+200 kg of N/ha |
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