Originally Posted By: reynante
... while the Sun Power Port provides a clean energy source...
The carbon footprint of every device could be roughly expressed by its price. $695.00 cost of solar panel device has a carbon footprint corresponding over 46 kWh for 15 USD/kWh (DOE price at the U.S. in April 2009), i.e. 63 days of permanent operation, i.e. at least 200 days of real operation (for ~8 hours of direct sunlight per day).

Just after 3/4 year of daily operation your device becomes "clean" source of energy. In real case (20 vaccation days per year) the pay-off period becomes prolonged to more then ten years...