Originally Posted By: andyd
Total bachelor of Arts idiot here. How big a collector would be needed to give the equivalent of 15 gallons of gasoline a day? How much green algae would be needed to create 15 gallons of gasoline?
Excuse me for crossing units, but a gallon of Gasoline contains 132MJ of energy. 1KwH contains 3.6MJ, so you need 36 of them to match the energy content of a gallon of Gasoline.
Go here
http://rredc.nrel.gov/solar/old_data/nsrdb/1961-1990/redbook/atlas/serve.cgi
and you can see how many KWh a square meter can collect in a day (that's what falls, then you have to convert it a whatever the efficiency of your collector is.
Electrical equivalent to gallons of gas isn't really that fair in one way, as the engine burns at 20% efficiency give or take while electric motors are in the 90s...but then the solar collection efficiency is only 20% anyway.
So that 8' collector is 4.7 square meters, would be exposed to 4-5Kwh per day (average), and harvest it at a generous 25%..gets 5.25KWh.
A Tesla Model S would go 21 miles on that, and it's about state of the art...throw in converting to hydrogen, and you get even less, as each intermediate step loses energy.
Just for giggles, go to the solar map, and see what you get from an 8' panel in Winter in Marshfield.