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What Gore Didn't Say About Solar Cells
AmericanInKiev writes "Computer World posted a piece on Al Gore and his claim that solar cells will improve at the same rate as microprocessors. Vinod Khosla on the other hand has expressed disappointment that the doubling rate for price/performance of PV is 10 years rather than 18 months for transistors. Which of these two has the facts on their side?" Before anyone has him inventing the Internet again, note that Gore's claim as related in the article is much milder than that Moore's Law applies to solar cells per se -- namely, he's quoted as saying "We're now beginning to see the same kind of sharp cost reductions as the demand grows for solar cells." An optimistic statement, but not a flat-out silly one.
Moore's Law talks about the complexity, not speed or performance. That's why it doesn't apply to either solar cells or digital camera sensors.
Digital camera sensors, especially, as it's not the complexity that kills ya, it's that it can't get physically smaller and still capture as much light (independent of the # of pixels). CPUs get cheaper because they get physically smaller, and thus require less silicon. The same deal with silicon PV cells - you don't want to make them smaller, you want to make them more efficient at converting light to electricity. Solar cells will indeed get cheaper (MUCH cheaper) very quickly (within the next few years, you'll see several competing technologies, in fact), but not due to silicon processes, but because they're going to be made without silicon (or with much less silicon, or silicon of a much lower grade than CPU-grade silicon (they've been competing for the same Silicon resources all this time)). I'm just sayin'.
There is a lot of research going on into improving not only the output of solar but into lowering the cost of manufacturing them. Nanotechnologies have in lab tests have shown certain avenues of current research may have the ability to increase performance of basically existing tech by as much as 25%, sure they are a ways to go before any kind of mass production can be done with this research but it's there. Increaseing acceptance by the population as to the usefullness of the equipment will of course generate more investor dollars into this research, and frankly I'd much rather see this than more research into increaseing payload output of bombs. Some areas stil have much they could do to encourage the adoption of solar too. being able to sell engery to the grid rather than just offset the cost of what you bought for instance in California alone would be a boon to the industry.
I Need someone to rebuild a Digitech Digital Delay pedal for me....for me...for me...for me.
Given that we have technology like CSP using mirrors and standard steam turbines, What do you feel is the best balance between improving what has already proved functional, or dickering around with a test tube? I see MIT has dye-impregnated acrylic, you have an asbestos, er nanotech, based material and some theories, while the European are building real working Solar plants at Utility scale.
I dunno, it just seems we're a bit heavy on the science experiments and little to slow on the Yankee Ingenuity these days.
In my town they built a natural gas power plant called the Cogen that takes the steam, and runs it to a large lumbermill next door, to power the equipment. Most lumbermills still use steam to drive saws and such, as it is more efficient (and cheaper) than straight power saws.. Kind of a neat idea for a "dual use" system
What are we going to do tonight Brain?
I wonder if it would make sense to run the leftover heat through a series of heat engines, with each optimized for smaller temperature differentials than the last.
It's referred to as a combined cycle. Many gas power plants recover the heat from the gas turbine and use it to run a steam turbine. GE claims 60% efficiency for their combined cycle turbines, where a standalone gas turbine would get around 35%.
It does not make sense to continue the process indefinitely. Eventually one will reach a point where building the equipment requires more energy than is produced from the ever-dwindling temperature difference.
But then again, I could be wrong.
The problem, though, is that we don't have much gallium. Definitely not enough to build whole square miles worth of solar panels.
Gallium is only found in trace amounts in Zinc and Bauxite ores. There is no gallium-high ore. Mostly we get a little of it as side effects of producing aluminium. It's enough for silicon doping and leds, but that's about it.
Even at the rate at which we're already using it, there's an estimate that the (easily accessible) reserves will be depleted by 2017. Can you imagine the rate we'd use it up for solar panels? Not to mention we'd need to dig out and process a _heck_ of a lot more bauxite than we currently do, to get that much of it.
So it seems to me that that plan is dead right there. There is no obvious way how to get lots of it, and the price will likely only go up from here.
Err, not really. You can use steam to produce electricity. Nuclear power goes the same route, btw. IIRC some 80% of the world's electricity is produced by steam turbines.
So, I don't know... any particular reason why we _can_ use heated water to produce electricity, if we heat it with coal or a nuclear reactor, but not if it was heated by the sun? It's the same process and with the same efficiency.
Plus, it seems to me that, from a pragmatic point of view,
1. A significant part of the world would rather have convenience, rather than sacrifice themselves for the greater good. I'd rather have a small stove in the kitchen, rather than a huge solar contraption. Plus, I'd rather cook when I want to, not just when it's sunny outside.
2. The world seems to have decided already that it wants solar-produced electricity.
3. We're actually pretty good at producing electricity from steam in the meantime. The big power plants get about 40-45% of the energy out of the fuel and converted into electricty. That's good enough.
But more importantly, it's better than what even the best uber-expensive prototypes of solar panels can do. So I'm kind of wondering, dunno, what's with the obsession with solar panels?
4. Transporting hot steam or hot water is pretty wasteful too. _Storing_ it, even more so. It needs a lot of insulation, and even so there are losses.
And it's done already, btw. I live in a town where the power plants also provide the hot water.
Let me tell you, when I want to take a shower in the morning, I first have to waste some cubic metre or two of water (no, seriously) just so I actually get hot water. Everything that was past the big insulated pipes, comes out as cold water first.
A polar bear is a cartesian bear after a coordinate transform.