Let's watch this test case

> In the long run, barring the discovery of new physical catalytic
> processes, I think we're going to rely more and more on platinum and
> the fuel cell technology.

While it is true I have argues for PV+Hydrogen+Fuel Cells as one
solution for producing and storing power locally without a grid, there
are many others in the wings (if one can believe press releases).

For example, see for example:
http://www.io.com/~frg/
Two concepts, TAC and MEMS-TAR -- both related to thermoacoustic
generators.

"The TAC generator is designed to produce power as a fuel fired primary
generator or waste energy recovery system. ... The TAC engine-generator
has only one moving part. Like a single piston in a V-8 engine, it can
be mounted in multiple units on a heat manifold to produce an engine
with megawatts of power. A demonstration video CD of a working engine is
available. (TAC < $0.25/Watt (W)"

"The MEMS-TAR ... This tiny MEMS thermoacoustic generator converts
heat into electricity. The source of heat can be solar radiation,
combustible fuel, even body heat. It requires no maintenance and is cost
competitive with all existing power generation equipment. (< $0.10 /
Watt) The MEMS-TAR is manufactured using the same equipment and
processes used in the manufacture of computer chips. It is packaged in
single discrete units, and in integrated panel arrays. Power
conditioning circuitry is built right into the chip. "

They are looking for investments for continued R&D. Both have much lower
proposed capital costs than anything else (figures claimed from that site):
MEMS-TAR < $0.10/W
TAC < $0.25/Watt (W)
Fossil fueled $0.43/W
Wind $1.00/W
Nuclear $3.50/W
Photovoltaics $6.50/W

They claim further at: http://www.io.com/%7Efrg/history.htm
"The TAR is robust, and can be built into a paving and roofing tile.
We have developed an iron orthosylicate building brick / roofing tile /
paving tile with high thermal mass (42 W-hr/lb), just for this purpose.
Sidewalks, roofs and parking lots can become giant solar collectors and
thermal storage mass. The same holds true for exterior walls of houses,
apartment complexes and shopping malls."

or:

http://www.borealis.com/power/index.htm

"Power Chips, which use electron thermotunnelling to convert heat
directly into electricity, will be one of the first industrial
applications of nanotechnology. These small, solid-state devices promise
to improve current power generation and waste heat recovery techniques.
Power Chips will deliver up to 70-80% of the maximum (Carnot)
theoretical efficiency for heat pumps (conventional power generation
equipment operates at up to 40% Carnot efficiency)."

I'm not going to argue that either of these specific companies really
have anything to offer (though they talk a good game). But my point is
that there is an active amount of R&D in these areas (see the various
links to other reasearch efforts at the FRG site especially -- DARPA,
Navy, NASA, Penn State, Los Alamos, Sandia), and there is nothing in
theory which prevents such systems from eventually working as described
or reaching those sorts of costs in mass production. Whether cheap PV or
cheap stirling-like engines on a chip or something else all of these
have in common the notion of improved materials science coupled with
clever ideas and practical engineering for mass production leading to
low cost power harvesting technology on Earth in the near future (and
not especially needing Platinum). So, if one resource like Platinum gets
expensive, these other energy harnessing paths can be pursued which
don't depend on them.

Thus, these small scale technologies or ones like them with continued
R&D will likely pass by any approach like SPS which requires twenty+
year investment lead times, and, unlike SPS, they have the potential
benefit of not needing to keep an expensive but vulnerable electrical
grid operating second by second and the social and political and
environmental consequences of that.

When we look at the SPS proposals, we have to be looking long term and
consider borad social issues given the scaleof the proposals. The
central problem then of SPS as an *investment* (which is how it is being
sold) is that it is a twenty+ year investment before any returns are
seen from it, which, to be made at low risk, requires predicting the
future of power technology twenty years from now to ensure such SPS
power distributed by a grid will be cheaper than locally produced power
using wind/sun/biofuels/etc -- even given our current skewed economy
(with greater tax preferences and legal preferences for fossil fuels and
centralized nukes). As power technology is increasingly linked to MEMS
(as the above examples show), and MEMS in theory long term can get close
to theoretical optimum for energy conversion of heat and sunlight in
mass production, I would think betting on the future of such devices for
local Earthly use is much safer than betting on SPSs with such a long
lead time. While it is true one can argue SPSs can use such advanced
systems, the issue then becomes is it better to generate and store power
locally or to generate more of it per unit mass continually in space and
then distribute it via a complex, expensive, and failure prone grid? I
would think that once costs are in the few thousand dollar range (so the
cost of a top of the line washer/dryer) for a ten year lifespan unit for
energy production and storage in a home which only needs simple annual
maintenance (like oil furnaces do these days) that people will prefer
the local solution, especially in the 80% of the world closer to the
equator and especially in places without reliable grids already.

But admittedly, since making a decision involves predicting the future
of a variety of technologies as well as projecting forward social and
political impacts related to centralization/decentralization, it is
unlikely we will ever all be in agreement on the best strategies. I
still feel it is less risky to rely on incremental R&D given I can see
the light at the end of the tunnel and rely on decentralization. Others
may disagree.

The problem in an SSI context, as I have said before, comes for me when
the notion of developing space habitats is then coupled with an econmic
investment idea like SPS which is for the reasons I have outlined seems
questionable as an investment related to energy production, given that
what may have made sense in the mid 1970s no longer makes sense in the
mid 2000s given all the material science research going on. The
alternative remains to pursue the NASA 1980s concept (or related Bernal
1920s concept) of the seed factory launched and growing into a habitat.
Yet, SSI has not historically emphasized such work (although I am
somewhat out of that loop for most recent directions, aside from
attending the last two conferences). The thing that concerns me most
reading between the lines at:
http://www.ssi.org/conference.html
is that SSI sounds about to make a big push for SPS and a related
militarization of space for asteroid defense. For reasons I have
outlined (at least for SPS) IMHO I question that approach very deeply.
But, I can see the general opinion on this list would be in disagreement
with me. :-) So, if SSI proceeds on that basis, I can only hope that all
the assumptions outlined in the case for SPS are correct and hold over
the next few decades.

All the best.

--Paul Fernhout