Analysis of Using Willow Trees for Ethanol Production
From Wikepedia Solar Cell on April 28, 2008:
http://en.wikipedia.org/wiki/Solar_cell
The power output of a solar array is measured in watts or kilowatts. In order to calculate the typical energy needs
of the application, a measurement in watt-hours, kilowatt-hours or kilowatt-hours per day is often used. A common
rule of thumb is that average power is equal to 20% of peak power, so that each peak kilowatt of solar array output
power corresponds to energy production of 4.8 kW·h per day.
...
STC specifies a temperature of 25°C and an irradiance of 1000 W/m² with an air mass 1.5 (AM1.5) spectrum.
These correspond to the irradiance and spectrum of sunlight incident on a clear day upon a sun-facing 37°-tilted
surface with the sun at an angle of 41.81° above the horizon.[7][8] This condition approximately represents solar
noon near the spring and autumn equinoxes in the continental United States with surface of the cell aimed directly at
the sun. Thus, under these conditions a solar cell of 12% efficiency with a 100 cm2 (0.01 m2) surface area can be
expected to produce approximately 1.2 watts of power.
- - - - - - - - -
From the above data, we can conclude that with 12% efficient solar cells, peak power would be 1200
watts per square meter.
Average power is 20% by the rule of thumb.
1 square meter would be 240 watts (20% of 1200 watts)
24 hours per day, means times 24 hours. This would be
5760 watt hours per square meter
5.76 kilowatt hours per square meter
Now for the German willow tree project on the previous page.
New process in Germany produces 5000 liters of BTL biodiesel fuel per hectare
1 liter is 40.9 migajoules
1 joule is 2.778*10^-7 kw-hour
1 megajoule is 2.778*10^-1 kw-hour = 0.278 kw-hour
1 liter of BTL is 40.9*0.278 kw-hours of energy
1 hectare is 5000*40.9*0.278 kw-hours of energy
57260 kw-hours per hectare
10000 square meters in a hectare5.726 kw-hours per square meter
Conclusion: The amount of energy from growing willow trees and converting it into BTL biodiesel
fuel is about 5.76 kilowatt hours per year. For 12% solar cells, it would be about the same amount of
power per day. The willow trees are a waste of time and money.
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From Wikepedia Solar Cell on April 28, 2008:
http://en.wikipedia.org/wiki/Solar_cell
The power output of a solar array is measured in watts or kilowatts. In order to calculate the typical energy needs
of the application, a measurement in watt-hours, kilowatt-hours or kilowatt-hours per day is often used. A common
rule of thumb is that average power is equal to 20% of peak power, so that each peak kilowatt of solar array output
power corresponds to energy production of 4.8 kW·h per day.
...
STC specifies a temperature of 25°C and an irradiance of 1000 W/m² with an air mass 1.5 (AM1.5) spectrum.
These correspond to the irradiance and spectrum of sunlight incident on a clear day upon a sun-facing 37°-tilted
surface with the sun at an angle of 41.81° above the horizon.[7][8] This condition approximately represents solar
noon near the spring and autumn equinoxes in the continental United States with surface of the cell aimed directly at
the sun. Thus, under these conditions a solar cell of 12% efficiency with a 100 cm2 (0.01 m2) surface area can be
expected to produce approximately 1.2 watts of power.
- - - - - - - - -
From the above data, we can conclude that with 12% efficient solar cells, peak power would be 1200
watts per square meter.
Average power is 20% by the rule of thumb.
1 square meter would be 240 watts (20% of 1200 watts)
24 hours per day, means times 24 hours. This would be
5760 watt hours per square meter
5.76 kilowatt hours per square meter
Now for the German willow tree project on the previous page.
New process in Germany produces 5000 liters of BTL biodiesel fuel per hectare
1 liter is 40.9 migajoules
1 joule is 2.778*10^-7 kw-hour
1 megajoule is 2.778*10^-1 kw-hour = 0.278 kw-hour
1 liter of BTL is 40.9*0.278 kw-hours of energy
1 hectare is 5000*40.9*0.278 kw-hours of energy
57260 kw-hours per hectare
10000 square meters in a hectare5.726 kw-hours per square meter
Conclusion: The amount of energy from growing willow trees and converting it into BTL biodiesel
fuel is about 5.76 kilowatt hours per year. For 12% solar cells, it would be about the same amount of
power per day. The willow trees are a waste of time and money.
Next
Options Index
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