Jones Beene wrote:
However, what's not clear to me is what would algoil be doing under
equivalent conditions at 9 am in December, when temperatures are
hovering around 15 - 25 degrees F, or less.
The prime location for any algae pond and CO2 sytem is adjacent to a
regular power plant, where the hot water from cooling the steam
generators (waste heat) heats the pond.
As far as I know, all of the present large-plans to grow algae use
waste heat and CO2 from power plants. Some pilot plants have been built.
It should be noted that there is a huge amount of waste heat from
power generation, so this method could recycle a lot of carbon. As I
said before, I expect the photosynthetic efficiency of algae in the
artificial environment would be much better than the natural 2%. The
waste heat from generators far exceeds the total amount of heat
generated by burning coal. See the figure on last page of this document:
http://lenr-canr.org/acrobat/NRELenergyover.pdf
Waste heat from generators is a little less than the 28.1 quads shown
here, because that figure transmission and distribution losses (T&D
losses). Coal produces 22.7 quads.
I wouldn't know, but I doubt that the overall conversion efficiency
of the algae plant can convert more than the equivalent of 5% of the
waste heat into biofuel with algae. It is not a direct, one-for-one
conversion by any means, but anyway if it is 5%, that would be 1.4
quads. The U.S. uses about 99 quads per year. Transportation uses
26.6 quads, so at 5% conversion, algae biofuel would supply 5% of our
transportation fuel, which is way more than corn ethanol would supply
if it were an energy supply instead of an energy sink.
This figure illustrates how transportation is by far the least
efficient sector. Industrial use of energy is the most efficient
sector. Overall, useful energy is 34.3 quads and rejected energy
(waste heat, T&D losses and so on) is 57.8 quads. This shows how much
leeway there is to save energy with better efficiency. I think
efficiency of up to 60% is possible in many major applications,
whereas transportation is mired at 20%, not far from where it was
when Henry Ford brought out the model T. The overall energy
efficiency of electric power generation could be vastly improved by
using more cogeneration.
For a big-picture look at energy, see:
http://www.eia.doe.gov/emeu/aer/pdf/aer.pdf
There is an interesting trend on page xxxv, Fig. 65. "In 1999,
transportation sector carbon dioxide emissions overtook industrial
sector emissions."
- Jed
