Breaking News! NASA Astronaut Marsha Ivins ****ting Her Diapers!

On Tue, 05 Jun 2007 15:52:41 -0600, in a place far, far away, Joe
Strout made the phosphor on my monitor glow in such a
way as to indicate that:

In article k.net,
robert casey wrote:

Powersats in LEO to me doesn't seem to be much better than just building
the thing on the ground.

That's OK; this is no doubt just because you haven't looked into them
very deeply.

At night, a powersat visible from the ground
will probably also be in the Earth's shadow.

Incorrect. A satellite in GEO is in sunlight 24 hours a day, except for
a brief eclipse for about 20 minutes (IIRC) twice a year.

Again, he was talking about LEO, not GEO. LEO powersats do indeed
have the problem mentioned, but there are mitigations, as I stated in
my other response.

"Henry Spencer" wrote in message
...
With one small caveat: some of the generating capacity now used only for
peak loads, which would have to run 24x7 if some new big off-peak energy
use appeared, is not suited to providing base-load power -- too expensive,
too polluting, etc. (Some utilities use older plants, or inefficient but
low-capital-cost technologies like gas turbines, to help meet peak loads.)
It would have to be replaced with new base-load generating capacity in
this scenario.

That's a point that a lot of those pushing electric vehicles miss. It still
takes x amount of power to move the vehicle (and the weight of batteries
often makes the vehicle heavier, requiring more energy). That energy isn't
free, it still has to be generated. Electric vehicles do not eliminate the
pollution cost of generation, it just shifts it from the vehicle itself to
the generating plant.

That having said, there *is* some reduction in pollution, because a big
plant generating power produces less waste and is more efficient than a
bunch of tiny plants, and although I haven't personally done the math, I
suspect the increase in efficiency more than makes up for the transmission
losses.

"Hyper" wrote in message
oups.com...
IMHO, nukes are the only reasonable way to cut CO2. They would replace
the worst source of pollution - coal. Incidentally, nukes would also
*diminish* radioactive waste released into the atm.

I believe they are the only reasonable way to increase energy production
until space solar power becomes available. There are a lot of alternatives,
such as wind and even wave, but they are niche sources and will never amount
to more than a tiny amount. Still, tiny is better than nothing.

If I can build the house I want to build, it will have solar power panels
and solar water heaters, and I will wire it for wind power to be added
later. I saw some turbines from the UK that supposedly could handle the
power load for a small office for around $25K, and I should break even on it
by selling power back to the utility. I plan to build in southern New
Mexico, where the sun and wind is constant enough for this to be practical.
Mostly it depends on how big a check I can write

I'm doing it less to save the world than I am trying to minimize my
dependence on the grid.

Scott Hedrick wrote:
"Henry Spencer" wrote in message
...
With one small caveat: some of the generating capacity now used only for
peak loads, which would have to run 24x7 if some new big off-peak energy
use appeared, is not suited to providing base-load power -- too expensive,
too polluting, etc. (Some utilities use older plants, or inefficient but
low-capital-cost technologies like gas turbines, to help meet peak loads.)
It would have to be replaced with new base-load generating capacity in
this scenario.

That's a point that a lot of those pushing electric vehicles miss. It still
takes x amount of power to move the vehicle (and the weight of batteries
often makes the vehicle heavier, requiring more energy). That energy isn't
free, it still has to be generated. Electric vehicles do not eliminate the
pollution cost of generation, it just shifts it from the vehicle itself to
the generating plant.

That having said, there *is* some reduction in pollution, because a big
plant generating power produces less waste and is more efficient than a
bunch of tiny plants, and although I haven't personally done the math, I
suspect the increase in efficiency more than makes up for the transmission
losses.

It's also a lot easier to apply emission control technologies to one
smokestack than to thousands of tailpipes.

"Jorge R. Frank" wrote in message
...
It's also a lot easier to apply emission control technologies to one
smokestack than to thousands of tailpipes.

Hadn't considered that, but a most excellent point.

Sometimes buying in bulk does save money

Joe Strout wrote:

:In article ,
: John Schilling wrote:
:
: SSP doesn't connect to oil prices, because SSP generates electricity and
: oil is almost exclusively used in applications where electricity is *not*
: an adequate substitute. You're thinking about "energy" as if it were a
: fungible commodity; it's not. There are two almost completely independant
: energy markets, one for fixed power and one for motor vehicle fuel.
:
:This will cease to be true when/if motor vehicles run primarily on
:stored electricity. Try http://www.google.com/search?q=Tesla+motors
:for example.
:

Well, shortly after Hell freezes over, then. I'll watch the weather
reports.

: And SSP is somewhat relevant to global warming, but mostly to the extent
: that it replaces Chinese coal-fired power plants and blast furnaces. But
: any plan to devote Sagans of American taxpayer dollars to building new and
: better power plants for the Chinese, is an absolute political non-starter.
:
:China is certainly important, but the US is at the top of total CO2
:emissions at least as of 2003:
: http://cdiac.ornl.gov/trends/emis/tre_tp20.htm
:

Get current. China is now at the top of the list. Worse yet (and
this is true of most of the developing world), its CO2 output per unit
of economic output is abysmally low by Western standards.

:
:Of course I realize that what matters is current and near-future
:emissions, not total past emissions. But the U.S. is at the head of
:that "current" list too, at least as of 2005:
: http://www.earth-policy.org/Indicato.../2006_data.htm
:

Again, get current. It's not 2005, either. It's 2007 and China just
screamed past us in the last few months (a good year or two ahead of
the projections).

Again, worse yet (and this is true of most of the developing world),
China's CO2 output per unit of economic output is abysmally low by
Western standards.

:
:Granted, China's got a lot of power coming online in the near future,
:but it's extreme head-in-the-sand-ism to say that US emissions don't
:matter. We're responsible for over 20% of the CO2 emitted on the
lanet. That's huge.
:

And we're responsible for over 25% of the global product. When we're
producing a bigger share of CO2 than we are global output, THEN we're
the problem. Until then folks like India and China are the problem.

:
: Furthermore, SSP is *percieved* as being absolutely completely totally
: irrelevant to anything in the real world, on account of being a hopelessly
: unrealistic fantasy.
:
:No argument there. Of course if it were demonstrated, even on a small
:scale, people would stop laughing. But as long as they're laughing,
:it's hard to demonstrate. This is the classic problem space development
:has faced over and over, occasionally with success (e.g. space tourism).
:

No, they'd just switch to laughing at anyone foolish enough to
actually invest in it, since even with high fuel prices it's not
economically viable.

: We need clean solutions to global warming and fossil fuels.
:
: Which SSP may not offer, and even if it does, how do you propose to get
: it? Shouting for massive government spending to develop SSP technology,
: however you propose to structure the program this time, *will not work*.
: And damn few of us will join you on that fool's errand.
:
:True. About the only hope I have for SSP is for some visionary business
:leader to do it -- maybe Richard Branson, who has deep pockets and an
bvious interest in both space development and clean energy. But I
:don't imagine that there's much we can do here to have any influence on
:it at all.
:

It'll have to be REAL deep pockets, because SSP is a money loser
compared to other power sources. It's going to have to be someone
with trillions of dollars to spend to subsidize this indefinitely.


--
"The reasonable man adapts himself to the world; the unreasonable
man persists in trying to adapt the world to himself. Therefore,
all progress depends on the unreasonable man."
--George Bernard Shaw

Joe Strout wrote:

It's not just about adding new capacity as needed -- it's about reducing
existing emissions, by replacing existing fossil-fuel-burning plants.

To provide power when existing sources reach limits, you have to
be cheaper than the other currently non-competitive alternatives.
Excluding fossil fuels, this means competing with nuclear.

To provide power instead of expanding existing sources, you have
to be cheaper than that (we still have lots of coal).

And to DISPLACE existing dirty sources, you have to be cheaper
than the MARGINAL cost of those existing sources. The existing
sources get to ignore their sunk capital cost, but you can't.
Even if you insist on reducing CO2 emissions, you have to compete
against retrofitting those existing plants with CO2 capture/
sequestration equipment, again ignoring the sunk capital cost.

Frankly, I will be utterly astounded if SSP can compete with
terrestrial power sources (even excluding coal) in my remaining
lifetime, and not at all surprised (in some theoretical sense,
after I'm dead ) if it can't compete this century.

Paul

Henry Spencer wrote:

Unfortunately, even Arizona gets clouded out at times, and atmospheric
absorption cuts available power early and late in the day (a particular
annoyance for the latter, since that's when the highest demand peak is).
And there is quite a bit of 24x7 base load to be supplied, and there'll
be much more of that if electricity is used to manufacture or replace
petroleum-derived liquid fuels.

However, if electricity is replacing liquid fuels, this will likely
require large amounts of battery capacity in vehicles. So you
automatically have most of a load-leveling system already in place.
You can do even better if the vehicles are hybrids, using sparing
amounts of some liquid fuel to tide themselves over rare periods when
generating capacity is unusually impaired.

Seasonal constraints are probably dominant, so the SSP ability
to wheel power between hemispheres can't be entirely countered.

Paul

Paul F. Dietz wrote:
Joe Strout wrote:

It's not just about adding new capacity as needed -- it's about
reducing existing emissions, by replacing existing fossil-fuel-burning
plants.

To provide power when existing sources reach limits, you have to
be cheaper than the other currently non-competitive alternatives.
Excluding fossil fuels, this means competing with nuclear.

To provide power instead of expanding existing sources, you have
to be cheaper than that (we still have lots of coal).

And to DISPLACE existing dirty sources, you have to be cheaper
than the MARGINAL cost of those existing sources. The existing
sources get to ignore their sunk capital cost, but you can't.
Even if you insist on reducing CO2 emissions, you have to compete
against retrofitting those existing plants with CO2 capture/
sequestration equipment, again ignoring the sunk capital cost.

Frankly, I will be utterly astounded if SSP can compete with
terrestrial power sources (even excluding coal) in my remaining
lifetime, and not at all surprised (in some theoretical sense,
after I'm dead ) if it can't compete this century.

All these SSP advocates completely miss the point. What we want to do is
demonstrate SSP on a small scale, for on orbit energy production and
consumption, in order to drive solar technology for use on Earth.

It's a technological development program, not meant to solve any energy
or carbon dioxide crisis directly, at least not in near term scenarios.

--
Get A Free Orbiter Space Flight Simulator :
http://orbit.medphys.ucl.ac.uk/orbit.html

"Paul F. Dietz" wrote:

Henry Spencer wrote:

Unfortunately, even Arizona gets clouded out at times, and atmospheric
absorption cuts available power early and late in the day (a particular
annoyance for the latter, since that's when the highest demand peak is).
And there is quite a bit of 24x7 base load to be supplied, and there'll
be much more of that if electricity is used to manufacture or replace
petroleum-derived liquid fuels.

However, if electricity is replacing liquid fuels, this will likely
require large amounts of battery capacity in vehicles. So you
automatically have most of a load-leveling system already in place.

Not true - as current assumptions are built around the electric
vehicle charging at night, precisely when solar isn't available (and
normal electric demand is at it's lowest). Charge them during the
day, and they compete for power rather than serving a load leveling
function.

D.
--
Touch-twice life. Eat. Drink. Laugh.

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL