Jones Beene quotes someone:
Valcent has extrapolated data from its test bed facility to conclude
that production yields of up to 150,000 gallons (3,570 barrels) of
bio-oil per acre per year are possible at a cost of about $20 per barrel.
Oh come now, that's absurd. Let us have a reality check here please!
Let's assume the system is a black hole that absorbs every joule of
sunlight and converts it into oil.
1 acre = 4,047 m^2.
Sunlight falling on 1 m^2 at the equator under ideal conditions
produces about 1 kW for ~6 hours per day (insolation in Africa); 4.2
kWh/day. For one acre, that's 17 MWh/day. See:
http://www.apricus.com/html/solar_energy_calculator.htm
Divide by 24 hour for continuous output and it comes to 0.708 MW/acre.
1000 acres, which this writer claims is enough for a power plant,
collects enough for continuous 708 MW operation with a black hole
collector. But we are talking about North America, not the Sahara
desert, and it is inconceivable that the thing is 100% efficient at
conversion. A pond filled with algae is not a black hole; it reflects
plenty of sunlight. I doubt the overall process of conversion is even
2% by the time you process the stuff into oil, but even at 5%
conversion efficiency in Africa you are talking about a 35 MW
generator, which is a lot smaller than most coal-fired plants.
Substitute North American insolation (4.3) and with 5% overall
efficiency and you get a 25 MW plant.
If the the technology emerges such that the strains of algae are
hybridized to be robust using only heat and CO2, such as those under
development which have been using single cell organisms hybridized
from deep ocean vents - then it may be possible to increase the
average yield up to nearer to the best case.
That would be a perpetual motion machine! You have to have energy
input into the system, which can only be sunlight in this case. In
the ocean vents, the input is geothermal heat.
If the system were operated on the scale of an average farm - with
1000 acres of these algae ponds, then the value of the oil produced
at 150,000 gallons per acre (best case) is at least $300,000,000 . . . .
150,000 gallons per acre per year?!? With 4.3 insolation, an acre
collects 12 MWh per day, assuming a black hole collector. Multiply by
365 days per year and you get 4,380 MWh per year. That converts to
120,000 gallons of gasoline per year, but again, this is not a black
hole. In real life it converts to 6,000 gallons. (Assuming they have
a fantastically effective 50% collection and conversion it would be
60,000 gallons -- still way short of 150,000.)
I did this by several different methods, but you can cheat and
convert kWh to gallons the easy way here:
http://www.mhi-inc.com/Converter/Energy%20Converter.htm
Also, $300,000,000 divided by 150,000 would be $2,000 per gallon.
This must mean $300 million for the 1000 acres, and the writer
assumes gasoline is worth $2 per gallon, or $84 per barrel.
Actually, gasoline is worth about $1 per gallon wholesale, and you
get only 5%, so it comes to $7,500 per acre ($7.5 million for the
1,000 acres.) The best legal cash crop in the world today is tobacco,
which is worth about $2,000 to $4,000 per acre, so this is pretty darn good.
Bear in mind that coal cost about 6 times cheaper than oil per BTU of
heat, so if you burn the oil in the generator, instead of using it
for transportation fuel, the cash value per acre falls to about
$1,300 per year. However, no one in the U.S. would burn oil to
generate electricity.
- Jed
