toms@ncifcrf.gov (Tom Schneider) (02/26/90)
In article <8145@pt.cs.cmu.edu> vac@sam.cs.cmu.edu (Vincent Cate) writes: > it would be really neat to use several >thousand watts of solar cells on my house to produce gasoline for my car. Plants make hydrocarbons, so we should be able to bioengineer a plant to extrude hydrocarbons, much the way maple syrup is tapped from a tree... If we get on it right away - we might have it in maybe 50 year's I'd guess. Could be much sooner. How long would a tree take to make a gallon of gas? We should be able to figure this out from the known rates of tree growth! This is a useful problem for the nanotechnology folks over in sci.nanotech to think about (so I am cross posting it there also). Tom Schneider National Cancer Institute Laboratory of Mathematical Biology Frederick, Maryland 21701-1013 toms@ncifcrf.gov [Well, in the case of maple sugar it's an incredibly inefficient way to do it. By far the best way would be some single-celled creature, in tanks. However, I imagine that nanotech will obviate the whole problem by allowing (a) direct, high-efficiency conversion of light to electricity, and (b) efficient, high-density storage of electric power. We shouldn't need to burn hydrocarbons in our cars at all. --JoSH]
dietz@cs.rochester.edu (Paul Dietz) (02/28/90)
>[Well, in the case of maple sugar it's an incredibly inefficient way to > do it. By far the best way would be some single-celled creature, > in tanks. However, I imagine that nanotech will obviate the whole > problem by allowing (a) direct, high-efficiency conversion of light > to electricity, and (b) efficient, high-density storage of electric > power. We shouldn't need to burn hydrocarbons in our cars at all. > --JoSH] But hydrocarbons are a good means of storing electricity, if the conversion from/to electricity is efficient (it's a lot easier to refuel a vehicle than to charge a battery, and it is much easier to stockpile fuel or transport it large distances.) This basically means having good electrocatalysts. Nanoengineering, even without full nanotechnology, promises to give us better catalysts. Even with today's hit-or-miss catalysts, there are some interesting results. For example, a copper electrocatalyst in 1 M KOH has been found to convert CO2 to ethylene at 69% faradaic efficiency. Paul F. Dietz dietz@cs.rochester.edu
isr@rodan.acs.syr.edu (Michael S. Schechter - ISR group account) (02/28/90)
I may be way off on this, but I was under the impression that current
solar conversion is up around 30% of theoretical, (for the best availible
solar cells) so I can't see nanotec making a big difference here. Also,
I'm curious to see if people out there can think of effective energy
storage methods involving nanotechnology?
Ones I can think of right now are
..better built batteries (boring)
..Molecular flywheel arangements?
..Molecular sized springs storing energy?
..mechanical charge transport mechanism?
or possibly direct light powering of any of the above, getting rid
of the Light->electricity->Storage->electricity cycle, giving us
direct Light->Storage->Kinetic Energy??
Any comments??
Mike
[Primarily in the cost arena, since the highest efficiency cells now
are not economical. However, with nanotech, high-efficiency conversion
may be remarkably simple: there's a good chance that you could just
build arrays of tuned dipole rectennas at optical frequencies!
Best storage methods will probably involve creating and storing
HEDM ("high energy-density matter") forms, using nanotech to store
them stably. Single-H, anyone?
--JoSH]