Shuttle Replacement Needs to Become a National Priority!!!

In article ,
Richard Morris wrote:
James Nicoll wrote:

Coal liquifaction should see us well into the 21st century,

22nd century

assuming the whole world industrializes (centuries if they don't).

And assuming global warming turns out not to be a problem.

Carbon can be sequestered. Also, people will put up with amazing
amounts of unpleasantness if they think their job depends on it. See "air
quality, London, prior to the Clear Air Act." It was safer to be in London
during the Blitz than it was to be in London during the killer smog.
--
http://www.cic.gc.ca/english/immigrate/
http://www.livejournal.com/users/james_nicoll

Paul F. Dietz wrote:

Solar power satellites are dangerous and expensive - only an L5 habitat
could make them economically.


I'm not convinced. I've seen a conceptual design of a modular
multi-gigawatt SPS that would be built with only terrestrial
materials, yet would require launching only a few thousand tons
into LEO. Nothing would need to be manufactured in orbit.

and it would require something on the order of 10,000GW of SPS
capability to make the slightest bit of difference here on Earth.

That's 4000 of your modular SPS's, or roughly four *million* tons going
uphill...

--
Terrell Miller


"Suddenly, after nearly 30 years of scorn, Prog is cool again".
-Entertainment Weekly

"Paul F. Dietz" wrote:

Richard Morris wrote:

Coal liquifaction should see us well into the 21st century,
assuming the whole world industrializes (centuries if they don't).


And assuming global warming turns out not to be a problem.

Add mineral carbonation to sequester CO2, or use the coal to
thermochemically produce hydrogen and sequester the CO2 at
the processing plant.

And how much of that uranium and thorium is recoverable at a reasonable
cost? Granite, basalt, etc. are pretty poor "ores", so the cost will be
relatively high at best.

With breeding, an average unit of granite has 20 times the energy content
of the combustion of the same mass of coal, and the cost of extracting
the uranium & thorium from that rock would be a small fraction of the
value of the energy produced.

But before we did that, we'd mine the oceans for uranium. Uranium can
be extracted from seawater (containing about 4 billion tons of U, a
at 3 ppb) for less than $1000/lb, and which (with breeders) would
contribute negligibly to the cost of energy. It's even possible that
the cost could be brought low enough to make this source useable in
advanced burner reactors.

If we could mine granite and extract the uranium and/or thorium for a
cost that was less than what the energy would sell for at the current
price, somebody would be doing it. If they are, I haven't heard about
it.

Ditto for the 3.3 ppb of uranium in seawater. 3.3 ppb is about 10,000
times less concentrated than any ore that has ever been successfully
mined. Gold is a lot more concentrated, and far more valuable, but I
haven't heard of anybody extracting gold from the oceans either. All of
the uranium that has ever been extracted from seawater would probably
fit easily in the palm of your hand. I will believe it can be done,
economically, when somebody builds a pilot plant producing uranium in
useful quantities (tons per year) over a period of one or two decades.
The oceans are not a friendly environment for high-tech equipment, and
it will take a considerable amount of operations to get an idea of the
real costs.

The last paper I saw on extracting uranium from seawater projected a
cost of about $1400 per pound, IIRC. It assumed that the plants would
be anchored in ocean currents to avoid the, apparently, crippling cost
of pumping the water through the filters. It also assumed that we would
burn coal to provide the required process heat. That does not sound
very practical to me.

(Have you calculated how many cubic miles of seawater would have to be
filtered per year to duplicate the energy we now get from fossil fuels?
And how likely is the public to accept an energy system dependent on the
production and distribution of hundreds or thousands of tons of
plutonium per year?)

Paul

James Nicoll wrote:

In article ,
Richard Morris wrote:
James Nicoll wrote:

Coal liquifaction should see us well into the 21st century,

22nd century

assuming the whole world industrializes (centuries if they don't).

And assuming global warming turns out not to be a problem.

Carbon can be sequestered.

It's already sequestered. Mother Nature has done the job for us, and I
frankly don't see much sense in digging it up and burning it and then
spending a huge amount of money and energy to re-sequester it.

Also, people will put up with amazing
amounts of unpleasantness if they think their job depends on it. See "air
quality, London, prior to the Clear Air Act." It was safer to be in London
during the Blitz than it was to be in London during the killer smog.
--
http://www.cic.gc.ca/english/immigrate/
http://www.livejournal.com/users/james_nicoll

Richard Morris wrote:

If we could mine granite and extract the uranium and/or thorium for a
cost that was less than what the energy would sell for at the current
price, somebody would be doing it. If they are, I haven't heard about
it.

Yes, but that's not what I said, or what the argument I was
critiquing required.

Uranium is currently very cheap, and contributes very little
to the cost of nuclear power. This is why we don't have breeder
reactor programs -- why develop a technology that conserves
uranium when the stuff is so cheap?

Uranium from granite, or from seawater, would be more expensive
than the current market price of uranium. But it would still
be cheap enough that we could afford to mine it and use it
in breeder reactors.

Ditto for the 3.3 ppb of uranium in seawater. 3.3 ppb is about 10,000
times less concentrated than any ore that has ever been successfully
mined.

The fact that the stuff is already in solution is a considerable benefit.

Gold is a lot more concentrated,

Wrong. The concentration of gold in seawater is orders of magnitude
lower than that of uranium. Uranium has this ion, uranyl, that
is nicely soluble in oxidizing conditions.

The last paper I saw on extracting uranium from seawater projected a
cost of about $1400 per pound, IIRC.

Now realize that a 1 GW(e) breeder reactor would consume roughly
a ton of uranium a year. That $3M/year would contribute $.0005/kWh
to the cost of this electricity.

Paul

"Terrell Miller" wrote in message
...

and it would require something on the order of 10,000GW of SPS
capability to make the slightest bit of difference here on Earth.

That's 4000 of your modular SPS's, or roughly four *million* tons going
uphill...

And 4 million tons is the mass of one of the smaller, first-generation space
habitats, of which the overwhelming majority of the material would come from
the moon, rather than the Earth.

That said, I should go on to say that large-Earthlike habitats won't be
needed to get started building SPS from space-derived resources. They can
come along later; the first generation of SPS workers will probably have
accommodations similar to those of off-shore oil-drilling platforms.

--


Regards,
Mike Combs
----------------------------------------------------------------------
Member of the National Non-sequitur Society. We may not make
much sense, but we do like pizza.

Terrell Miller wrote:

and it would require something on the order of 10,000GW of SPS
capability to make the slightest bit of difference here on Earth.

That's 4000 of your modular SPS's, or roughly four *million* tons going
uphill...

At (say) $1000/kg, that would be about $4 trillion.

As opposed to tens of trillions of dollars for an equivalent
terrestrial energy infrastructure. No showstoppers here.

Paul

Richard Morris wrote:
Carbon can be sequestered.

It's already sequestered. Mother Nature has done the job for us, and I
frankly don't see much sense in digging it up and burning it and then
spending a huge amount of money and energy to re-sequester it.

Why not? The net energy gain after sequestration is still
nearly as high as it is without sequestration. The "huge amount"
is significant, but less than is spent to extract it and then
burn it in the first place.

That we're burying the reaction products again doesn't mean that
the cycle doesn't work. If it's economic to do so, and despite
regular pronouncements of doom and gloom from environmentalists
and luddites, it is, then we can do it and probably should,
if CO2 is a problem.


-george william herbert

Richard Morris wrote:
The last paper I saw on extracting uranium from seawater projected a
cost of about $1400 per pound, IIRC.

One pound of Uranium contains about 3E13 J of energy.
In BOTE terms, 1E10 Wh. At 10% net efficient conversion,
1E9 Wh, or 1E6 KWh. Or roughly 0.14 cent per KWh.

I currently pay 11 to 13 cents per KWh delivered to my house
on the electrical grid.

Your economic paranoia is innumerate.


-george william herbert

George William Herbert wrote:

Why not? The net energy gain after sequestration is still
nearly as high as it is without sequestration.

In principle, it might even be higher. Mineral carbonation
is net exothermic.

Granted, in practice it probably wastes some energy
to overcome slow kinetics. OTOH, it also could produce,
as side streams, enough nickel, chromium, and platinum
group elements to swamp existing markets.

Paul