Frederick Sparber wrote:
Jed keeps harping on the low (2%?) solar conversion efficiency of
growing biomass
It is probably lower than that for general agriculture, but once again,
that figure is meaningless as -- and so is the 40% efficiency number for
new solar cells.
These cells might achieve 40% at noon in July after being cleaned, yet
only 10% at 9 am in December with the normal coating of grime which
silicon picks up rapidly -plus- the main point is that they are
extraordinarily expensive compared to ponds and plumbing (for CO2).
NREL has reported tank grown mixed algae strains which can surpass the
40% efficency figure anyway, and generally algae will continue to
multiply for several hours after the sun goes down.
The only comparison which counts in the least - therefore, is this:
How much net energy, averaged over a full year, can be captured and
stored per dollar of investment, less incremental costs.
Under these criteria, which are the only ones which matter, it would not
surprise any expert if the advantage of algoil over advanced silicon
solar-cells turns out to be in the range of 50 times more energy
returned per dollar of investment.
Jones
