More fuel for thought

Dan Luke wrote:
On Tue, 15 Apr 2008 16:55:04 GMT, wrote:


The challenge is extracting the full solar spectrum and storing it.
But there are no fundamental scientific reasons why this is not
achievable.

You mean other than we haven't a clue how to do it in the real world?

There are no fundamental scientific reasons why we can't:

Convert light into electricity with 90% efficiency.

Cure cancer.

Produce sustainable fusion.

Convert junk mail and coffee grounds into 100 LL.

You're just a happy little ray of sunshine, aren't you?

Yeah, you're right: we don't know how to do any of this stuff.

Might as well give up on all of it.

I never said that.

But since I've spent most of my life building stuff that had to adhere
to both the laws of physics and economics, I'm probably a lot more
inclined to be practical rather than to go wishing on a star and hoping
something that doesn't exist suddenly does.

The odds are good that the cost of electic production will fall in
the near (decades) term, but it will be from plants firmly anchored
on the ground.


--
Jim Pennino

Remove .spam.sux to reply.

In a previous article, "Private" said:
I just found this on another forum, facts not verified, no commentary made.

Huge Dakota oil pool could change energy climate debate

By Dennis T. Avery
web posted April 14, 2008

Al Gore is launching a $300 million ad campaign to support the banning
of fossil fuels. But our faith in man-made global warming will now be
tested by news that up to 400 billion barrels of light, sweet crude
oil for America's future can be pumped from under Manitoba and North
Dakota. That's more oil than Saudi Arabia and Russia put together.

You know, when the article starts off with a blatent lie, and everything
it says about climate science is a 100% verifiable bold faced lie, it's
really hard to believe what it says about the oil "pool".

I don't have time to refute all the lies about climate science, although a
few minutes with any article written by a real climate scientist (or even
a Wikipedia article or two) should be enough to do that.

So let's start with the first sentence in the article. "Al Gore ... to
support the banning of fossil fuels". Al Gore isn't dictator of the
world, so you'd think if that was his goal, he'd have to actually come out
and say that was his goal to try to convince people. Ok, I've read two of
his books, seen the movie, watched a couple of his speeches, and looked
all over his web site algore.com, and nowhere does he say "I want to ban
all fossil fuels".

Al Gore founded The Alliance For Climate Protection, whose web site
http://www.wecansolveit.org/ states as one of its goals "begining a
transformation towards a robust clean energy economy". That doesn't sound
like an outright ban to me. Maybe it's because I'm a liberal and a
scientist, and maybe it's because because I actually read what they were
proposing instead a summary provided by somebody with an axe to grind and
a less than stellar commitment to the truth, but that sounds like a
responsible process where we replace dirty energy with clean energy at a
pace that is based on what is economically sustainable.

--
Paul Tomblin http://blog.xcski.com/
"Tower zero one request clearance for takeoff."
"Cleared runway three contact ground point six three when off the runway."
- Michael Crichton destroys whatever technical credibility he had left.

On Apr 15, 2:45 pm, wrote:
ons why we can't:

Convert light into electricity with 90% efficiency.
We are already doing it, for specialized applications. Internal
quantum efficiencies of certain semiconductor materials have
approached nearly 100% within a narrow spectral range.The challenge is
how to translate that to match the broad solar spectrum. The know-how
exists, but there isn't enough investment to make it happen.

The best efficiency achieved in a lab to date is around 40% of the
total incident energy of the sun's spectrum.

That is why I said 'the challenge is how to translate that to match
the broad solar spectrum'. A narrow band emission can be converted to
electrons with extremely high efficiency. We are already doing it.
Look up the quantum efficiency of any high-end photodetector.

A challenge can be overcome. Fundamental physical limits cannot be
overcome. The quantum efficiencies of todays solar cells are due to
limitations of implementation, not due to a fundamental limit, similar
to the Carnot cycle. If you use a single material (silicon) and a
single junction, it will do poorly with a broad band spectrum,
especially the portion of the spectrum that lays above 1.1um
wavelength.

I can make a 90% efficient solar cell in the lab. Split the solar
radiation into many spectral components, and use a high QE detector
for each spectral range. Make your detectors out of GaN, GaP, AlGaAs,
GaAs, HgCdTe to cover the entire spectrum. That is the crude way to do
it, and will cost enormous $, and will never be practical. But it is
not an impossibility. There is much we can do to improve solar cell
efficiency. The focus needs to be there.

On Tue, 15 Apr 2008 18:55:04 +0000, jimp wrote:

Both of you are ignoring the fact that you get that only if the angle
beteen the sun and your collector is 90 degrees,

So we'd have to pitch and bank for best power? Big deal. That's what
makes it fun.

Laugh

- Andrew

Andrew Sarangan wrote:
On Apr 15, 2:45 pm, wrote:
ons why we can't:

Convert light into electricity with 90% efficiency.
We are already doing it, for specialized applications. Internal
quantum efficiencies of certain semiconductor materials have
approached nearly 100% within a narrow spectral range.The challenge is
how to translate that to match the broad solar spectrum. The know-how
exists, but there isn't enough investment to make it happen.

The best efficiency achieved in a lab to date is around 40% of the
total incident energy of the sun's spectrum.

That is why I said 'the challenge is how to translate that to match
the broad solar spectrum'. A narrow band emission can be converted to
electrons with extremely high efficiency. We are already doing it.
Look up the quantum efficiency of any high-end photodetector.

A challenge can be overcome. Fundamental physical limits cannot be
overcome. The quantum efficiencies of todays solar cells are due to
limitations of implementation, not due to a fundamental limit, similar
to the Carnot cycle. If you use a single material (silicon) and a
single junction, it will do poorly with a broad band spectrum,
especially the portion of the spectrum that lays above 1.1um
wavelength.

I can make a 90% efficient solar cell in the lab. Split the solar
radiation into many spectral components, and use a high QE detector
for each spectral range. Make your detectors out of GaN, GaP, AlGaAs,
GaAs, HgCdTe to cover the entire spectrum. That is the crude way to do
it, and will cost enormous $, and will never be practical. But it is
not an impossibility. There is much we can do to improve solar cell
efficiency. The focus needs to be there.

Actually, the real challenge isn't efficiency as that only matters
where you are weight limited, such as spacecraft.

There isn't enough surface area on conventional vehicles to gather
enough power to be usefull no matter the efficiency.

The real challenge is dollars/watt, total installed cost.

--
Jim Pennino

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"Phil J" wrote in message
...
On Apr 15, 2:47 pm, Gig 601Xl Builder
wrote:

I don't know of anyone who is suggesting that we trash the world
economy.

There are lot's of Greens out there that would do exactly that and if
the truth were known they would be happy about it. These are the same
people that were pro-USSR prior to the 90s. They are watermelons. Green
on the outside and red on the inside. That is a friend of mine's
favorite saying. He probably got it from Rush but it is a pretty good
description.

: Really? How many Communist Greens have you met that wanted to trash
: the world's economy?

All of them.

"Jay Honeck" wrote in
news:cVUMj.67331$TT4.15571@attbi_s22:

The current president also renewed the treaty that cedes oil
rights to a significant portion of the Florida Straits to Cuba,
which in turn leases their rights to the Chinese and others.

Which indicates the Republicrat (nee: statist) Congress needs a
massive enema.

I was merely pointing out some common fallicies about offshore
drilling.

Both parties are to blame for the energy mess we're in. Neither party
offers any answers.

We *need* a third political party in the U.S.

You re an idiot.


Bertie

"Jay Honeck" wrote in news:eOVMj.67389
$TT4.59838@attbi_s22:

People need to get over the utopian idea that there's some vast
untapped oil resource out there, but we're somehow being prevented
from using it.

http://tinyurl.com/54rp3x

Whoops! Another utopian idea reinforced....

;-)

In your tiny mind, yes.


I propose a new approach to democracy, where you get multiple votes if
you read and none if you just watch Fox news, like Jay does.

It's worth a try..

Bertie

On Apr 15, 3:46 pm, (Alan) wrote:
In article Andrew Sarangan writes:


As for 100 percent efficient solar cells, you say:

We are already doing it, for specialized applications. Internal
quantum efficiencies of certain semiconductor materials have
approached nearly 100% within a narrow spectral range.The challenge is
how to translate that to match the broad solar spectrum. The know-how
exists, but there isn't enough investment to make it happen.

If you believe that, you should be out convincing investors that you
can make them very rich. Don't tell us. Show us.

That is a very simplistic view. This is not at a stage where a
business could be created. This is still at a stage where federal
investment is necessary. One can't do this without significant
investment in R&D. There are myriad of ideas, but little $ to fund
them.

When someone suggested in the 1940's that a man-made satellite could
be made to orbit the earth, I am sure many people told him 'Don't tell
us. Show us'.




Had we spent all the post-911 terrorist-aversion expenditures on
something like this, we could be declaring independence from the
middle east.

Speculation, with no facts in evidence.

Take a look at where we (U.S) stands in R&D spending per GDP compared
to other industrialized nations. We rank 7th. How much money do you
think has been spent post-911 on unnecessary security measures, such
as the fence-example I mentioned?



On the other hand, NSF (National Science Foundation) budget has barely
kept up with inflation in the past 10 years. This is where we count on
for fundamental break throughs in discovery.

Last I checked, the NSF didn't do research. Universities do some, but
putting things into production is done by businesses.

Nor does NIH, DARPA, ASOFR, ONR etc..
Transitioning a technology to production is the last phase of a long
process. It is overly simplistic to think that research and
commercialization are compartmentalized.

"Andrew Sarangan" wrote in message
...
On Apr 15, 3:46 pm, (Alan) wrote:
In article

Andrew Sarangan writes:

If you believe that, you should be out convincing investors that you
can make them very rich. Don't tell us. Show us.

That is a very simplistic view. This is not at a stage where a
business could be created. This is still at a stage where federal
investment is necessary. One can't do this without significant
investment in R&D. There are myriad of ideas, but little $ to fund
them.

Venture Capital.

When someone suggested in the 1940's that a man-made satellite could
be made to orbit the earth, I am sure many people told him 'Don't tell
us. Show us'.

The idea of satellite in orbit pre-dated the 1940's by quite a spell.

But it's always more fun to spend other people's money.