Re: Irish Electricity II


Si wrote:
Michael mused to which kevin replied:

"> Finally, Hydrogen-Oxygen cycle engines produce water as their
product.
Why are there no H/O engines yet?

I don't think the tech is really there yet. Seems to me that one
problem is that the only catalyst they've been able to get to deliver
the goods is platinum and that they don't have cell size down yet.
there might be some other stuff, but its eluding me just now "



There are many issue with a hydrogen fuel system. The first is storage,
at room temperature Hydrogen is a gas. It is a highly combustible gas.
You would have to store it at significant pressures to get anysort of
meaningful amount. i.e. enough to get you too the shops and back. The
higher a gases pressure the easier it is to tip it the wrong side of a
Chapman-Jouget line and get it to go bang. You could, I suppose, store
it as a cryogenic liquid a la space programs. That has its own
problems: the most remarkable thing is that liquid Hydrogen is just not
that dense. There is an apocryphal story of the early years of the
space race when the US was using liquid hydrogen. There was an on going
security problem with the tanker trucks that hauled the liquid hydrogen
about the place. They were designed to look like petrol tankers but
they only needed one axel on the rear of the trailer because the fully
loaded mass was so low. However this kept attracting the attention of
the state troopers who suspected the axel was overloaded and kept
pulling them into weighing stations. Eventually they stuck a second
dummy axel onto the tankers So for a hydrogen powered system you need a
much larger volume tank for the fuel. You would have a hellish problem
storing the liquid hydrogen over long periods too. You would need some
sort of active thermal management to keep it in the tank of your car
and not venting all away as it heats up over time. There is also the
problem of hydrogen embrittlement in a lot of common materials that
would effect the logevity of wetted surfaces. Also hydrogen being the
smallest atom there is can leak out of just about anything.

http://www.eere.energy.gov/hydrogenandfuelcells/tech_validation/pdfs/fcm03r0.pdf


Thanks for the info and the link.


On the nuclear front it's a bit like the original Sunningdale
agreement. It is the only long term option but we all have to wait for
the slow learners. There is no realistic green option that can give us
the power desity and reliability of nukes. Bio-mass won't give us
enough but has it's place. It is a no net carbon system true. But it's
still pumping out CO2. Wind, solar and wave are too unreliable to be
used on their own. Hydro is limited in the locations that it can be
used and has it's own ecological problems. Also the scales that would
be required to replace hydrocarbon generation are staggering.


These are roughly the conclusions I'm coming to. All of these
technologies have their place. And, it to be earnestly hoped that they
will assume a greater share of enegry production. But, the fact is that
they do suffer from some intrinsic limits, at least presently. Most of
the big hydro sites hereabouts have been developed (over-developed,
actually. The Endangered Species Act has cut back on some production to
save salmon runs).
Wind is limited by whether it blows. While proper site selection
can reduce this problem, there will always need to be a backup to wind.
I'm getting to the point where I'm convinced that nuclear power is the
best backup. While natural gas is attractive as a backup from the
standpoint of capital costs (really, what you need is a jet engine), I
think it will soon suffer from the same geopolitical problems as we
currently see with oil. Plus, it does emit carbon. Coal is the most
likely substitute for nuclear power. We have a lot of it and its almost
as cheap as dirt. So, its immune to the geoplotics and price swings
associated with natural gas. But, its hella dirty and I don't believe
for a moment that gassification will actually sequester the carbon on
anything like a permanent basis.
Solar suffers some problems that are similar to hydro: it works
best in sunny climes. On the other hand, it is a technology that is
consistently improving and advances may make it way more accessible.
But, at least for the foreseeable future, it ain't gonna do it on its
own.
A couple of observations about slow learners. I think you've got
more than one type. First, there's people like me who grew up saving
the whales and stopping the nukes. This is mainly an educational issue.
You have to get a bunch of liberal arts majors to actually sit down and
understand the technology so that they understand that 60 odd years of
refinement has made it a reasonably safe proposition.
But, the second group is convinced by short-term economics, not
social conscience. Until recently, I viewed Florida as the Anti-Christ
for electing Shrub to his first term. But, I had taken my eye off the
ball. Coal producing states actually made the difference. You see,
those states have a loooooooooooonnnnnnnnngggggg liberal tradition. The
coal areas of those states all sided with the Union during the civil
war (witness for example, West Virginia. the stroies out of Eastern
Tennessee are even more poignant. There was perhaps no greater example
than neighbor fighting neighbor and reprisal killings and executions.
Kansas-Missouri might have been worse, but not by much). In this
century, these areas were key in breaking down racial barriers by
building solidarity in the coal unions (oh, black and white together,
we shall not be moved. Our union is forever, we shall not be moved).
But, now, the growing awareness that coal is a main contributor and
major future threat to the atmosphere has them siding with the
Republicans. And, that's just common working folk. Imagine what the
real money is doing. This is likely a greater problem than convincing
middle-class liberals.

Managing solid nuclear waste material is a comparatively simple
logistical problem when compared with manging gaseous carbon dioxide
emissions. We could dump the stuff in remote tectonic subduction zones,
deep mine storage, chuck it into space: there are a myriad of options.
How are we going to get the CO2 down? Hold our breaths?

Couldn't agree more.


In stark terms the problem is this. We have an exponential demand for
power. We need to provide this power AND reduce the athmospheric
carbon. Nuclear is the only way to square this circle. Renewables have
their place but to insist that they are the be all and end all is just
a smug conceit of the developed countries. Will the peoples of Asia,
Arabia, Persia, South America and eventually hopefully Africa pause in
their race to our standards of living just so we can pontificate on the
polite protocols of power generation?

Exaclty. And who are we to tell them they can't have the life we have.
Or, at least some fraction thereof. The first wave will not be denied,
its here in the form of China and India. So, we have two billion more
folks that are going to be using electricity in growing amounts. And,
where's the jsutice in denying the second wave. Why shouldn't we be
trying to bring the other two billion - people who don't see
electricity even at the village level, people who spend a fair portion
of their day gathering sticks and dung to cook a meal that we
accomplish by turning a dial on the stove? So, In the end, we are
looking at a lot more people generating a lot more carbon. In the end,
it will kill the children of rich and poor nations alike. Floods in
Bengeladesh will be matched by tropical disease incursions in Texas and
California. People of european ancestry are, by the way, the most
vulnerable to these bugs.



Whatever the truth of the Iranian nuclear program, proliferation of
nuclear power is a necessity.

Yes. I think its really more a question of integration. If I'm
understanding this fuel cycle correctly, it would be quite possible to
limit enrichment and plutonium production in such a way as to maintain
global safety (in terms of nuclear weapons proliferation) while
recycling fuel that is discarded from reactors requiring higher
enrichment in reactors with architectures that don't require high
levels of enrichment. Obviously, this also reduces waste. And, I pretty
much agree with you that the waste is manageable.

McCabe

.

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