On Sun, 9 Dec 2001, Mike Lorrey wrote:
> Photosynthesis is, at best, 3% efficient (compared to 35% for
> photovoltaics).
I think thats "natural" systems. I've seen discussions that
suggest that in photobioreactors you may be able to get up to 8-9%.
> Since we've already previously examined, analysed, and
> roundly dismissed photosynthesis as a viable energy alternative for
> technological civilization, anything less efficient should be similarly
> dismissed.
Its entirely a infrastructure cost issue. You can (a) invest in
self-replicating "natural" systems that will reproduce themselves
with very little investment (other than upfront engineering
costs) or you can build more and more solar collector factories that
you are going to be little used in the long term. The self-replicator
approach is *much* faster and cheaper than the factory building approach.
In the long run, building the factories makes sense (actually building
the factory that builds the factories is what really makes sense),
but in the short run it may be much more efficient to go with pseudo-natural
systems at a poor 4% efficiency and take the money you save in so doing
and dedicate it to designing the factory for the factories for the highly
efficient long-lived solar cells.
You ultimately want a self-repairing system that can repair or replace
parts damaged by UV. Until those are designed into solar cells the
natural systems may have certain low maintenance cost advantages.
Robert
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