SPS vs. solar/wind/hydrogen debate (Long Post)

On Tue, 25 Nov 2003 01:46:14 GMT, "TangoMan"
wrote:

Except that many in the 'environmental' movement are preaching 100%
Yeah. The practical problems are incredible. I'd say 25% - 35% is probably
the limit for solar/wind contribution. The rest has to be reliable baseload
power.

Nuclear could do it, if we could somehow get rid of all the legal
obstacles. :-)

So we have to cover MORE area, in order to produce enough hydrogen
It becomes a vicious cycle that doesn't make sense but it appeals to
environmentalist visions of nirvana and living in balance with nature.

That's the point I was trying to get across. The so-called
'nature-friendly' technologies really aren't. Organic farming methods
can't come close to meeting worldwide food demand... wind and solar
power may be good supplemental sources, but they can't take care of
total power demand without obliterating the habitats the
environmentalists hold dear.

"TangoMan" wrote in message
news:wrywb.490553$9l5.89409@pd7tw2no...

"Pete Lynn" wrote in message
...

Electricity generated from the wind is still typically more
expensive
than electricity generated from fossil fuels. Fossil fuel or
hydrogen
power generation might achieve a maximum of 60% efficiency.

I'm not sure what you mean by this. Wind turbines typically produce
power for about 35% of a day, but sometimes the site where they
thought they could get the 35% efficiency only produces 10% but
the project is still profitable because of tax credits.

Actully I think a 25% utility is more typical.

Is this along the lines of what you meant?

No, this is yet another problem. Making hydrogen from wind energy is
akin to placing two inefficient thermodynamic cycles, (plus hydrogen
distribution), on top of an already economically borderline wind energy
source. This is currently prohibitive.

Thus wind energy would have to cost less than a third of what it
currently does before this hydrogen transmission would be
economic.

Usually, wind power becomes economic when it can be produced
for less than the fuel costs of a fuel burning plant. That's a tough
standard to crack.

Exactly, hydrogen generated from wind energy has to be cheaper than
fossil fuel costs, prior to power generation. This means electricity
generated from the wind must be something like a fifth the cost of
electricity generated from fossil fuels in order for this to break even.

Hydrogen might more typically generate power at say 40%
efficiency with regard to transport applications. Obviously there
are various costs and inefficiencies involved with making
hydrogen, and perhaps making and storing LH2.

Very true.

Although hydrogen might be made and used at slightly
higher efficiency than synthetic hydrocarbons, it is arguable that
synthetic hydrocarbons would still be more practical for many
applications.

The analysis shouldn't be restricted to just the fuel but also the
costs
incurred in ancillary infrastructure - millions of fuel cells,
platinum
scarcity, hydrogen storage, etc.

Yes, though the restricted analysis is damaging enough.

The utility of wind turbines is typically 25%, one of the great
advantages of SPS is the ability to operate all the time, this has
all
sorts of benefits and should not be under appreciated. Personally
I am highly doubtful of the long term economics of SPS. There are
terrestrial alternatives that I expect to continue to reduce in
cost,
and to get there first, against this I do not see SPS anytime soon.

IMHO, the analysis hinges on how many SPS are implemented in
order to defray the orbital infrastructure costs that will be common
to every SPS built.

Yes and no, CATS could probably be achieved for a couple of hundred
million, at least an order of magnitude less than is spent on space
launches every year, yet we still do not have CATS. I fear that large
scale development of SPS would invariably follow the Space Shuttle
model, this will be far from economic. Initially, SPS needs to follow
the small private start up approach, as per CATS. It is not immediately
obvious how the scale problems might be overcome, but I suspect SPS
should start by serving power demands in space.

A significant space presence including Lunar resources should see
the real world commercial development of space solar power and
the maintenance thereof. This should significantly benefit the
economics and development of SPS, I would be interested to
know to what extent.

Depends on volume of orbital resources used. If you have a robust
orbital economy, and the price of steel, aluminum, PV cells, etc are
just a bit higher than they are on Earth, then calculate how much it
would cost to build a SPS on Earth with no provision for launch
costs. I thnk you'll see that you can build it very cheaply per MW of
power produced.

That is my hope.

I suspect it might change them enough, and so I expect that SPS
will become economic, but not until after we have a significant
space presence.

Chicken and egg. If the orbital infrastructure is there, then SPS uses
it and doesn't have to fund its establishment. And SPS is very
competitive.

Yes.

But if not for SPS, why is all that infrastrucutre in orbit?

The market that will drive space settlement is space settlement, there
is not really any way around this. While opportunities should be taken
where they arise, corrupting SPS into driving space settlement would be,
corrupt.

Imagine how cost effective coal, wind power, etc would be if they
had to fund the iron mine, coal mine, smelter, road network, power
plants to provide the power to make the steel, farms to grow food
for the workers at the steel mill, iron mine, coal mine, then build
the
housing for the workers, ad infinitum. They'd be in the same league
as SPS.

Yes, exactly.

Pete.

"TangoMan" wrote ...

"Derek Lyons" wrote in message
The sci.* and specifically the sci.space.* folks generally are not so
accepting.

Really? I don't see any posts starting with proper salutations. The absense
of such saluatations seems to me to be indicative of a laxer standard in
e-mail and usenet etiquette.

Try including a few "could of done" etc. in your posts and see what
happens.

Most people don't care if you make the occasional mistake, but if you
continuously make the /same/ mistakes after they've been pointed out to
you ...

"TangoMan" wrote ...
The purpose of this post is to summarize the debate on the merits of Solar
Power Satellites against Terrestrial Solar Power and Wind Power

And take a certain position in doing so. Not that I see any horrible
inaccuracies from my brief glance through but you can either try to write from
neutral standpoint from the facts or you can write to support your personal
opinions. If you are interested in getting people from /all/ sides to think
rationally about your arguments then the former is preferable. At a minimum
that means dropping name calling and insults - however deserved you may
think they are.

On Tue, 25 Nov 2003 19:02:26 +1300, "Pete Lynn"
wrote:

model, this will be far from economic. Initially, SPS needs to follow
the small private start up approach, as per CATS. It is not immediately
obvious how the scale problems might be overcome, but I suspect SPS
should start by serving power demands in space.

Only if we allow it to be a NASA/Government project... :-(

But if not for SPS, why is all that infrastrucutre in orbit?
The market that will drive space settlement is space settlement, there

I don't think so. Space settlement will evolve out of the
requirement to keep large numbers of people in orbit, not just 'to be
there'. Nobody would have settled in California if it wasn't for the
gold rush... there has to be a reason for people to be there first.

Lunar/NEA mining, some kind of manufacturing presence, SPS
development, etc. will drive the space-settlement movement, not the
other way around.

"John Savard" wrote stuff wot I have snipped ...

I have to hand it to you. I've rarely seen a post start so reasonably
and degnerate so thorougly.

(Len Lekx) wrote in message news:3fc27b83.953583964@nntp...
On 24 Nov 2003 09:58:38 -0800, (Alex Terrell)
wrote:

Not an insurmountable problem. Some illustrations...
1. Britain as a whole is pretty close. As long as you have the
capacity to shift electricity around.

Britain, perhaps... but what about North America? We're
having trouble interconnecting provinces and states, so
interconnecting the entire continent would be a tough nut to crack.
:-)

I think North America needs to invest significantly in its
distribution system anyway. For offshore power generation, I'd put a
high voltage DC link offshore from the Bay of Funday down to about
North Carolina. South of that you get too much hurricane risk.

For places like central USA, offshore wind won't help.

2. Even a single offshore site comes pretty close to constant wind,
unlike on shore sites.

Not every country has access to sufficient offshore sites.
How many wind turbines could be placed off the coast of Newfoundland
before the environmental movement starts screaming that we're
displacing fish habitats...?

Actually, offshore wind turbines are good for fish, because they stop
fishing. Fishermen complain, but they don't have enough fish anyway,
and even they benefit since offshore foundations enforce fishing free
spawning zones.

Newfoundland presents the challenge of ice, though they seems to
manage this OK in the Baltic.

dishwasher decides to run my hybrid car's battery charges up. If
there's no wind, or if demand is very high, my car's feul cell will
start up, and start pumping electricity into the network.

...And when you drive out of town on business, the dishes
don't get done...? ;-)

With a grid, as long as everyone doesn't drive out of town at the same
time, it's no problem. Bear in mind a household averages a few KW, and
a car could produce 10s of KW.

If we move to a hydrogen economy with wind power generating hydrogen,
then we have full storability and there's no longer an issue.

If we're going to go offshore for our energy resources, I
think Ocean Thermal generation might be the way to go.

I was watching a rather scary (or perhaps alarmist) documentary about
how Global warming could switch off the gulf stream and plunge Britain
into a Quebec type of climate. Could Ocean thermal have similar
consequences? It's not a very rich energy source (a temperature
differerence of 15-25C) so huge volume flows are needed. Another
concern could be that this would bring up sea bed methane deposits. If
these can be captured, great, if not, methane is a powerful greenhouse
gas.

On Tue, 25 Nov 2003 10:30:48 GMT, (Len Lekx)
wrote:

I don't think so. Space settlement will evolve out of the
requirement to keep large numbers of people in orbit, not just 'to be
there'. Nobody would have settled in California if it wasn't for the
gold rush... there has to be a reason for people to be there first.

John Sutter, the guy in whose mill pond gold was discovered, was a
settler in California. He had established a colony and was doing
quite well when the Gold Rush descended upon him.

There were Europeans in CA quite some time before gold was discovered.
Read Henry Dana for a contemporaneous account of the estancia system.

Mary

--
Mary Shafer Retired aerospace research engineer

On Tue, 25 Nov 2003 10:25:32 -0800, Mary Shafer
wrote:

John Sutter, the guy in whose mill pond gold was discovered, was a
settler in California. He had established a colony and was doing
quite well when the Gold Rush descended upon him.

I stand corrected. Apologies.

On 25 Nov 2003 09:44:15 -0800, (Alex Terrell)
wrote:

Actually, offshore wind turbines are good for fish, because they stop
fishing. Fishermen complain, but they don't have enough fish anyway,
and even they benefit since offshore foundations enforce fishing free
spawning zones.

Never considered that. Hmmm... the turbine foundations could be
laid out as artificial reefs... :-)

Newfoundland presents the challenge of ice, though they seems to
manage this OK in the Baltic.

The problems of ice were dealt with when the Confederation Bridge
was built - similar techniques might be employed for windmill bases.

time, it's no problem. Bear in mind a household averages a few KW, and
a car could produce 10s of KW.

Why not just use a generator...? Save the wear&tear on the car.
;-)

how Global warming could switch off the gulf stream and plunge Britain
into a Quebec type of climate. Could Ocean thermal have similar

Not that there's anything wrong with the climate in Quebec. (Bear
in mind that you're talking to a Canadian...)

OTEC systems *do* require large volumes of water - that's one of
the selling points. Besides using the temperature-differential
between surface and deep-sea water, the minerals brought up could be
separated out and exported.

consequences? It's not a very rich energy source (a temperature
differerence of 15-25C) so huge volume flows are needed. Another

Are wind-turbines really that different...? You have to cover a
LOT of area to get any significant fraction of what a modern nuclear
generating station produces.

concern could be that this would bring up sea bed methane deposits. If
these can be captured, great, if not, methane is a powerful greenhouse
gas.

So do deep-sea geological surveys before choosing a site for your
OTEC. If there's a hydrated methane deposit in the vicinity, you rule
the site out. There's a lot of ocean, even if you restrict yourself
to the areas between the tropics, where such a generator could be
placed.