Letters to the Editor
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Ignoring an obvious point...
The question asked if solar could meet all of our energy needs, and Pablo only talked about electricity demand. Electricity accounts for only a minority of energy consumed in America. Count everything else and you will end up needing a lot more than 1/3 of Rhode Island to meet that demand, but in fact electricity is simply not a viable substitute for many of these purposes (flying a jet plane, for instance).
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Scientific American had an article on this
...that showed how it is possible. Nonetheless, all eggs in one basket seems a bit silly, and even though it is possible, diversification is better.
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Plane
Well, it could indirectly fly that plane in the future.
Boeing is working on hydrogen powered airplanes. Hydrogen could be produced with electricity from solar, wind, etc.
But, you're right, many new technologies will have to converge to solve the multitude of energy and fossil fuel related problems we face.
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errr
thermal solar? thermal solar? anyone?
http://www.ausra.com/
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Photovoltaic fixation
This article is fixated upon the idea that the only way to generate electricity by solar means is to use photovoltaic panels, which are expensive and resource-intensive to build.
There are real solar plants being built today that use a much more simple and proven technology, concentrated solar thermal energy. Mirrors collect the sun's rays and this is used to heat something (often a fluid, sometimes something more exotic like molten salt), which is then used to generate electricity.
You don't need millions of tons of silicon, metric or otherwise, to build these plants.
And there are many novel ideas for power storage for these sorts of plants, mostly involving storing heat overnight (like a giant thermos). It isn't perfect, and the people who are developing this technology willingly concede that there will still be a need for baseline power generation that solar won't be able to fill without marked improvement in power storage.
Nor are they advocating that we sequester off 10,000 square miles of Arizona desert to power the whole country. Obviously, large-scale commercial solar deployments would be spread out across bright and sunny areas.
The technology behind large-scale solar generation is already here. We just need to invest more heavily in it to refine it and make it a very serious part of our energy policy. The sun doesn't charge more for its rays the more we use, so as the cost of nonrenewable energy continues to rise, it will not be too long before solar is competitive, and we'd be fools not to plan ahead for when that happens.
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Holy mackeral
The hundred square mile estimate is for solar thermal, not photovoltaics. And it wouldn't all be in one place. And there are promising ways to store the heat when the sun isn't shining. I'm no expert, but even I know more about this than Mr. Paster.
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CAES (compressed air energy storage)
A way to really get solar to work for the whole country has already been studied and a paper written on it.
http://www.sciam.com/article.cfm?id=a-solar-grand-plan
Compressed air energy storage, photovoltaics, solar thermal electric, wind, HVDC (high voltage direct current) transmission. They have studied projections out to 2100 with 95% replacement of fossil fuels, plugin hybrid cars. A conservative projection based on 2020 possibilities of technology advances.
Iowa is developing compressed air energy storage with their wind fields.
http://www.princeton.edu/~cmi/research/Capture/Presentations/CAES.ppt
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How much roof space is going to waste?
Why do we need to set aside miles and miles of desert, when there are all those roofs going unused? Sure, we need to diversify - but wouldn't it be nice if a large part of the energy needs of the Southern states were produced by solar panels on each individual roof?
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The efficiency is bit overstated
" Solar photovoltaic modules or panels convert beams of energy from the sun -- photons -- into electrons, which we can then use as electricity. According to Dan Berger, senior project designer at SPG Solar, we can expect to generate about 6.5 kilowatt-hours (kWh) per square meter of solar panels per day, or 2,373 kWh per square meter per year."
Solar radiance density is about 1000 watts/m**2 - if all the energy falling upon a 1 meter square panel was converted to electricity, then maybe you could obtain 6.5 kilowatt-hours per day. But, a photovoltaic panel is about 10% efficient, so you'd get 0.65 kW-hour per day ( 1000 watts * 10% = 100 watts average output times 6.5 hours). Even solar thermal panels are limited by the Carnot cycle to 50 - 60% efficiency at best.
I didn't check the rest of the math...
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maybe solar + wind & geothermal, just leave biofuels out of the equation
Sorry, had to share this article - directed to those whose comments suggest a combination of solar and other means:
www.time.com/time/magazine/article/0,9171,1725975-4,00.html
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We'd kill ourselves smelting that much silicon
So it's a win win.
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renewable energy
Get all non-renewable energy production out of the picture. "Clean coal", nuclear, oil and any other depletable energy source will lead to the blackmail we are currently undergoing, with companies like Exxon stealing us blind to the tune of $40 profits last year and bush's buddies the gulf countries holding us hostage. As somebody mentioned, Ausra has a very simple technology that can put an end to our dependency, and quickly. It will bring along with it entrepreneurship, competition, and efficiency, something the big energy companies fear. Ausra has several papers discussing the technologies involved. The way they write it up, it is very doable,
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And congrats on the new gig @ GHG
sounds interesting.
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AHHH, but there is another way
Study: Solar Thermal Power Could Supply Over 90 percent of U.S. Grid Plus Auto Fleet
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sorry
My link didn't work, plus I see that concerntroll already posted a link to the ausra site.
The Forbes article: http://www.forbes.com/businesswire/feeds/businesswire/2008/03/06/businesswire20080306005986r1.html
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Both right and wrong
As many others have pointed out, photovoltaics (what Pablo means by "solar panels") is just one technology in the group of technologies that's generally referred to by the catch-all "solar panels".
But apart from that Pablo is generally correct about the size of the resources and land-use problems that super-sized photovoltaic arrays would pose...
...except that he discounts the fact that photovoltaics (PV) is a maturing technology. Even efficiency figures from as recent as 2005 are obsolete, as a very large amount of funding is going into reducing the materials cost, and increasing the efficiency of PV.
And he also discounts that any move from "on demand" energy generation (nuclear, gas, coal) to "stored" energy generation (wind, solar, etc.) would require massive changes in how we use energy (lighting, domestic recapture of mechanical energy, glazing technologies, etc. etc. etc.)
So, a good article as far as it goes, but it raises FAR more questions than it answers.