"Robert J. Bradbury" wrote:
> On Thu, 20 Dec 2001, Doug Jones wrote:
> > Microwaves beamed in from elsewhere are less disruptive than any other
> > source of zero-entropy energy; heat engines on Earth's surface release
> > more waste heat than they produce electricity, and ground solar
> > dramatically lowers the albedo in the regions affected. Rectennas can
> > have a neutral impact on global thermal balance if they are painted
> > white.
> Doug, it wasn't the rectennas I was concerned with it was the waste heat
> from the use of the electricity. Cities already generate their own
> local weather patterns due to the fact their temperatures are higher
> than surrounding land.
> And yes, I agree that at current power consumption levels, it would
> probably not be a "significant" problem. But as Robert Freitas points
> out in Nanomedicine it only takes ~10kg of actively operating nanomachinery
> per person to put us over the global hypsithermal limit.
Does this account for using the waste heat of one's nanomachinery in a
cogeneration mode, to supply the heating/cooling needed for one's own
habitat? Just how much nanomachinery would one individual actually need?
What about the fact that the use of nanomachinery only speeds up the use
of energy into a smaller time span than occurs in nature, which is
completely separate from the issue of how much the individual uses their
nanomachinery? For example, today I build my house of wood that is grown
by trees over a 20 year period from solar energy at an efficiency of a
few percent. Tomorrow I instead pour 10 kg of nanomachinery on the
ground, which over the course of several weeks builds my house for me
from the same soil, air, and sunlight that a tree would have used if I
had planted one there instead. A wood house requires tens of thousands
of board feet of wood, equalling a number of trees covering a much
larger area than that occupied by the house.
The nanomachinery would not only feed off of sunlight for energy, it
would exploit the organic bonds of many different compounds in the soil
to power the conversion of that matter into construction materials.
Those organic bonds would otherwise have naturally released their energy
into the environment anyway through natural processes, so that energy
released is not "new".
> Once we have
> "unlimited" off-planet to planet power sources -- are you going to limit
> the size of your augmentation agents down here on Earth? One has to
> realistically plan for the idea that more than X kW/person and you
> have to migrate into space. Better that we start being aware of
> the problem sooner rather than later. There is a side benefit that
> I'm sure that some will like. The lower you keep the planetary
> power consumption the greater the sensitivity you have to people
> releasing uncontrolled self-replicators. So limiting the on-planet
> energy consumption gives you much longer lead times with regard
> to terrorists releasing self-replicating agents.
I think the inaccurate assumption is that off-planet power sources are
simply going to be added to current power sources, rather than supplant
them. While it is safe to assume that power demand will rise over time,
it is also safe to say that as beamed power becomes more competetive
than fossil or other sources, it will supplant such sources in the
market, and fossil fuels will fall out of use, just as the use of
'producer gas' from steam treating coal in many cities fell out of use
early in the 20th century when it became non-competetive.
If beamed power supplants fossil fuel use, then there will be no net
increase in heat added to our climate.
This archive was generated by hypermail 2b30 : Sat May 11 2002 - 17:44:29 MDT