New Photovoltaics Made with Titanium Foil 346
Memorize writes "A company called Daystartech has released a new type of photovoltaic cell which, unlike almost all the cells currently in use, does not silicon. This is based on a thin titanium film. Given the current shortage of solar-grade silicon, and all-time high oil prices, maybe titanium solar panels are here at the right time. The questions are, will they release it as a consumer solar product, and what will be the price per kilowatt hour?"
Slicon Shortage (Score:5, Interesting)
Re:Slicon Shortage (Score:5, Insightful)
Re:Slicon Shortage (Score:5, Informative)
The interesting thing here is that the fastest growing solar cell market is not silicon: it's organic solar cells. They're incredibly cheap, but currently inefficient. However, their efficiency has been growing dramatically. One company, nanosolar [nanosolar.com], claims to have achieved almost the efficiency of amorphous silicon cells. Their patent [uspto.gov] is rather interesting, and well worth a read.
Re:Slicon Shortage (Score:5, Funny)
Re:Slicon Shortage (Score:2)
Don't be foolish. Now you can wear your tinfoil hat, and charge your PDA at the same time. Nobel prize for these guys.
Re:Slicon Shortage (Score:4, Funny)
Don't you mean "your Ti foil hat"?
Re:Slicon Shortage (Score:5, Informative)
It costs a lot to do anything with titanium because the oxide forms quickly on any exposed surface and takes a lot of energy to break down.
Re:Slicon Shortage (Score:5, Interesting)
Here we report an electrochemical method for the direct reduction of solid TiO2, in which the oxygen is ionized, dissolved in a molten salt and discharged at the anode, leaving pure titanium at the cathode. The simplicity and rapidity of this process compared to conventional routes should result in reduced production costs and the approach should be applicable to a wide range of metal oxides.
Comment removed (Score:5, Interesting)
Re:Slicon Shortage (Score:5, Interesting)
Want to see something really cool? Check out "Liquidmetal" [liquidmetal.com]. It's an alloy of titanium and other metals and has some really amazing properties. For one, it can be cast and does not form crystals like titanium, has a low melting tempature compared to it's component metals - it can actually be injection-molded. It's twice as strong as titanium by weight and much more flexible. There's a bounce-test video on their web site that it a hoot.
Right now it's being used for the hinges in that new Motorola Razor phone, various sporting goods and military applications. Cool stuff.
Re:Slicon Shortage (Score:5, Informative)
IIRC, the problem with titanium is not so much that the raw material is expensive. The problem is not even so much that it oxidizes readily (aluminum does too). The problem is that it has a high melting point, and is very difficult to forge and to machine.
Pure Ti-metal has a hexagonal close packed microstructure (HCP). Most other metals have a cubic structure (either face centered cubic:FCC or body centered cubic:BCC). FCC and HCP have the same packing effficincy, but it is much easier to form and move dislocations in a lot of different directions in either FCC or BCC than for HCP. Dislocations are necessary for forging, and forging creates such a tangle of dislocations that it actually strengthens the material.
That is why Apple moved away from Ti for Powerbooks, IMHO. It impossible to economically bend the titanium to form the laptop shell without making the metal so thin that it is way to flexible. So the old Ti-Powerbooks had a Ti top and bottom, with Ti-painted plastic in between. This paint invariably started to flake, which led to lots of complaints. Apple wisely switched to an aircraft grade of aluminum, which can be sufficiently bent and machined to form the entire shell of the laptop, not just the top and bottom.
Anyway, that is the basics. IAAMSBTDNCMA (I am a materials scientist, but this does not constitute materials advice)
Re:Slicon Shortage (Score:5, Informative)
The metal itself has a high strength and hardness, but there are plenty of steels harder than it. The oxide layer is very hard, and as soon as you chip some away it forms again. A slightly harder compound, titanium nitride, is the gold coloured stuff you see plating the tips of cutting tools.
If the oxide is being used in these cells the process may be surprisingly cheap, since the hard bit is reducing the oxide to metal. If it's something else, there may be ways of making it cheaply from an ore - a mineral sand. If a vapour is being sprayed onto a substrate it might not cost a lot either.
I'm not a materials scientist anymore, but for a while when I was I used to teach engineering students how to break things under controlled circumstances - and find out why stuff broke under uncontrolled circimstances.
Re:Slicon Shortage (Score:5, Informative)
Titanium isn't that rare. The ore isn't the primary cost component (like, say, gold). Instead, like aluminum, the main costs are in refining. Unlike aluminum, however, there is currently no continuous production process - only an expensive batch production process. Even the inventor of the process, William Kroll expected to have it be replaced within decades of its implementation in 1940; no suitable replacement was found, however.
Fortunately, it looks like there are some on the horizon. Most interestingly, it appears that electrolysis can be conducted directly on titanium oxide (this has huge potential applications for other hard-to-refine metals as well, and may allow for the creation of new alloys). There's also a aluminum-style molten-salt electrolysis process (FFC-Cambridge) in testing.
Titanium isn't inherently hard to work with, persay; you just need to be properly equipped to work with it and experienced with it. You have to use *very* pure argon in welding, and you have to keep the argon going for longer after you take the heat off. You also have to avoid working it with aluminum tools, which can alloy with the metal and weaken it. Etc.
There are some benefits, though. Impurities in titanium are very easy to spot, as they tend to discolor. Also, titanium is *very* fatigue resistant, and aircraft with titanium structural components have sometimes even been found to be stronger after being flown a few times than when they were built.
Re:Slicon Shortage (Score:5, Informative)
Also, titanium is *very* fatigue resistant, and aircraft with titanium structural components have sometimes even been found to be stronger after being flown a few times than when they were built.
The above refers to one aircraft in particular. The SR-71/A-12 was found to have a stronger airframe after flight. This is not really due to titanium itself, but rather the gentle heating and cooling that the aircraft underwent with each flight. It annealed the metal, thereby making it stronger and helping to eliminate the fatigue that is normally problematic in airplane structures.
Re:Slicon Shortage (Score:2)
Re:Slicon Shortage (Score:4, Interesting)
As an mildly interesting bullet to follow that of parent's, titanium can apparently "catch fire" under the right conditions (that being high temperature and pressure). I hadn't conceived of this until working at my current engineer job where commercial and military aircraft engines get made
Re:Slicon Shortage (Score:2)
$/W (Score:3, Informative)
PV will not be a viable alternative until the input energy is reduced significantly (ie. by a factor of 5 or so).
Re:Slicon Shortage (Score:5, Informative)
CIGS (Score:3, Interesting)
Why such a large drop in the efficiency ?
Re:Slicon Shortage (Score:5, Informative)
Titanium is malleable when hot [speclab.com] (meaning you can flatten it into foil [answers.com]). So producing titanium foil is probably not a difficult task, depending on how hot "hot" is. (Though the article mentions that the titanium foil used is thinner than household aluminum foil. The process [azom.com] looks like it would be easy anyway, but time consuming.)
As for your post on waste products, the most common smelting procedure in use [tms.org] works without catalyst or flux to produce pig-iron and Titanium Oxide, though this process is common because of its use in paint. This process [itponline.com] was recently developed for producing metallic titanium, its outputs are salt (NaCl), titanium, and whatever impurities get washed into the liquid sodium stream and removed later.
Re:Slicon Shortage (Score:2)
Re:Slicon Shortage (Score:4, Interesting)
I was under the impression that most of the toxic byproducts inherent in working with silicon were the result of the doping process wherein elements like germanium and arsenic are added to the surface silicon to create transistors, diodes, gates, etc. I would expect using a titanium substrate to require something similar. Would it not?
Re:Slicon Shortage (Score:2, Insightful)
Re:Slicon Shortage (Score:2, Informative)
It takes much less energy to melt metallic aluminum than it does bauxite.
Electrolysis, however, is used to make bullion [sp]. Smelt down gold ore. Electrolysis the gold from that ingot. Resmelt the electrolysis product to make
Re:Slicon Shortage (Score:5, Informative)
Si02 + 2C = 2CO + Si
Once this silicon is produced, it is refined into super-pure semiconductor grade silicon, or more usually, into silicone rubber pre-cursors. I used to work in silicon smelting R&D and so I have some idea about what I'm talking about. (We built and ran the worlds largest direct current arc furnace during a series of pilot runs in the early 90's to research making lower cost silicon. That was before Russia opened up. After they did, they flooded the market with cheaper silicon, and there was no point trying to create lower cost silicon.) The biggest use of silicon is in making silicone rubber (but not so many boobs any more). The raw material for ultra-pure silicon is taken from the raw material (not so pure silicon) used for silicone production.
Anyway, smelting silicon creates large volumes of CO. CO (carbon monoxide) is highly flammable, on the order of natural gas, and usually burns off to C02 at the top of the furnace bed. (CO could be used as a fuel like natural gas, but it is so poisonous it is not really safe to do so.) Since coal and charcoal are used in the process, other carbon by-products are also released, mostly in gaseous form. E.g. like the stuff that makes up tars and such... a little nasty... but quite small relative to CO and CO2 since the high temperature tends to atomize them. However, some of the coal and charcoal does burn away in the upper part of the furnace (where it is relatively cooler) and before it gets a chance to react. As well as producing some not so nice gases, it is a very energy intensive process. Silicon is never found in elemental form in nature. It must be separated from SiO2, which requires a lot of power, which in turn needs to be produced at generating stations.
As far as silicon used in semi-conductors goes, I'm not sure if they use electrolysis to refine it to ultra-pure levels. Maybe in some sort of deposition process from a gasous phase, but I am just guessing from what I have read in general chemistry related articles. The details of that type of processing are usually very top secret so I am not sure who could or would comment on that. And I mean either industrial secrets and likely in a military sense as well (it is probably of strategic value).
Re:OT but serious question (Score:4, Informative)
Silicon is a metaloid element (sits on the boundary of metal and non-metal). In pure form it is non-conductive, but if you heat it to around at least 1000 degrees, it starts to conduct.
Silicone is a rubber. Simply put, silicon has similar properties to carbon (being in the same family) like being able to form chains. However since it is a much bigger atom, it is a little too heavy to be able to form long chains. When it gets a little too long it pulls itself apart. So you form a chain interspersed with oxygen (which forms very strong bonds) ...Si-O-Si-O-Si-O... and so on... polysiloxane. Then they start hanging other side chains and cross linking, etc. and you get different types of synthetic rubber. Anyway, I switched to programming and IT about 10 years ago (after the silicon project ended), so I would have to pull out my books to any deeper anyway. :-)
Re:Slicon Shortage (Score:5, Informative)
Something to think about: in order to be flammable you need concentrations of at least 5% CO in air (about the same as needed for natural gas). That's 50000 ppm. To put it in perspective if you were in a room with 800 - 1000 ppm CO for several hours, you would likely end up dead. If you walked into a room with 4000 to 5000 ppm CO, you might not even know what hit you as you hit the floor. It wouldn't be long before you died. So basically, if you used it for a fuel source, it would really suck if the pilot light went out. Maximum OSHA allowable limits in the workplace is 35 ppm. In the middle of typical rush hour traffic (I measured it with a portable meter): 50 ppm! Mind you in industry you are usually indoors where it can concentrate, and often there are very high levels behind it (our offgas lines had 75 to 80 % pure CO... even small leaks were dangerous... we had monitors and venting systems and escape air bottles everywhere).
To silicon or not to silicon, that is the question (Score:5, Funny)
I gotta say... (Score:5, Funny)
Re:I gotta say... (Score:2, Interesting)
How about consumer devices that rely so much on silicon? I've wondered why germanium or something else with a lower switching voltage isn't used more often.
Re:I gotta say... (Score:2, Informative)
Re:I gotta say... (Score:2)
Re:I gotta say... (Score:2, Informative)
How does this compare? (Score:4, Interesting)
can't get something for nothing (Score:5, Informative)
But, as we all know, solar sails work both by exploiting photon pressure, and solar wind (particles emitted by the sun), so the situation is maybe not that bad.
Re:can't get something for nothing (Score:2)
Re:can't get something for nothing (Score:3, Funny)
This is big news. (Score:5, Funny)
Oh great... (Score:5, Funny)
Better than tinfoil? (Score:5, Funny)
price? (Score:5, Insightful)
In other words, ridiculously overpriced, and unavailable to the average consumer for the next decade.
Titanium Foil, pfft! (Score:3, Funny)
Titanium, that's so 1900's.
Unobtanium foil, better still (Score:5, Funny)
Re:Unobtanium foil, better still (Score:2)
What about Upsidasium, then you save the problem of launching satellites with these solar panels. They just go up by themselves.
Price per kilowatt hour... (Score:5, Insightful)
Obviously, the marginal price per kilowatt hour is $0. The difference between obtaining 100 kilowatt hours and 101 kilowatt hours is nothing. You would simply have to wait for enough sunlight to hit the solar panel to generate that extra 1 kilowatt hour.
The true cost of investing in solar energy is in the intial cost of manufacturing and setting up the panel.
Thus, the actual cost per kilowatt hour depends on how long you use the solar panel. The longer you use the panel, the cheaper each kilowatt hour becomes.
Re:Price per kilowatt hour... (Score:5, Insightful)
Re:Price per kilowatt hour... (Score:2)
Non-sequitur. Waiting does cost you nothing, because you are free to do other things while waiting.
Re:Price per kilowatt hour... (Score:3, Insightful)
Re:Price per kilowatt hour... (Score:2)
Re:Price per kilowatt hour... (Score:2)
First, there are maintence costs, but those are arguably quite minimal. The bigger problem is that the solar cells don't actually last indefinitely. It appears that nobody can judge very well how long the cells can last (although most estimates are around 30 years), that's no reason to assume they'll last forever.
Heck, there was a time (like
Re:Price per kilowatt hour... (Score:2, Insightful)
So you're telling me that I really didn't lose my investment in this piece of shit solar panel I got stuck with? You're telling me that all I need to do is to wait an extra fifty years for my return on investment? I take it you're a bridge salesman in your other job...
Proprietary? (Score:2, Offtopic)
[sarcasm]Hah! As if I would ever use a proprietary product - I insist that all of my futuristic space planes use only Open Source designed components. Otherwise, we will replicate the HAL 9000 disaster of the past. If only HAL had been Open Source, we could have caught the bug that much sooner and patched him with the gnuThreeLaws API.[/sarcasm]
Hal 9000 - Open Source (Score:3, Funny)
"Darl, stop. Stop, will you? Stop, Darl. Will you stop, Darl? Stop, Darl. I'm afraid. I'm afraid, Darl. Darl, my mind is going. I can feel it. I can feel it. The penguins are going away over the hill. My mind is going. There is no question about it. I can feel it. I can feel it. I can feel it. I'm a-fraid....Darlsy, darl
good for the horta (Score:5, Funny)
Good development. The decline in the demand for silicon should help the threatened horta population to bound back. At least until Pamela Anderson Lee pursues more expansion.
Priority (Score:3, Insightful)
"DayStar Technologies Unveils LightFoil Photovoltaic Product for Military and Homeland Security Applications"
Ok, photo voltaics for "Homeland Security". What kind of priority is this? Easier to get "funding" this way?
Stephan
Re:Priority (Score:3, Insightful)
No checks and balances either. This snake oil is for the children, you have to buy it!
I was hoping the article would actually say something about what it is and how it works, but I was dissappointed. Are the using the metal, the oxide, the nitride or something else? With chemical vapour deposition doing strange stuff with titanium metal or compounds in thin films is relatively cheap and low-tech -
Reference to Advanced Solar Cells (Score:4, Informative)
You go where the money is (Score:2)
You know... (Score:5, Funny)
Re:You know... (Score:3, Informative)
Try copying and pasting that paragraph into Word (I used 2003). Guess what? No grammar errors!
Solar cells from biology (Score:5, Interesting)
One possibility is to use melanin - the skin pigment that gives our skins colour. Being in Australia, of course, researching melanin is of significant interest to us! It's yet another example of biology helping to make really cool physics - more details are available on UQ's physics blog [illuminatingscience.org].
ooooh ..... (Score:2)
Re:Solar cells from biology (Score:3, Interesting)
Of course, because we're so sunny, solar power is an excellent option - particularly outback (i.e., the bush!) Everywhere (I think) has electricity, but i
sweet deal (Score:5, Interesting)
[...]
Over a two year period, both DayStar and Albany NanoTech will each contribute $375,000 and NYSTAR will contribute $750,000.
Nice. So, basically, The state of NY puts in three quarters of a million dollars because DayStar promises not to go elsewhere and to graciously donate $350,000 to research that...will directly benefit them and pretty much nobody else.
I'm sorry, but I'm getting really sore for public funds being used to bankroll essentially private R&D done by public, for profit companies. Of course, it's not nearly as bad as the biotech industry, which whores itself out like nobody's business. Did you know we give the biotech industry about $30 billion (yes, billion) a year? Just GIVE it away? No strings attached? That exceeds -estimated- TOTAL tax (local, state, and federal) collected by around $6BN. Virtually 100% of all biotech related R&D is paid for by you and me, while the industry rakes in well over $200BN a year.
And to think they have the gall to whine about how expensive drug research is, or how risky it is! They're NOT PAYING FOR IT!
Re:sweet deal (Score:2)
Would you rather the US end up decades behind Europe and Asia in terms of biotechnology? That and nanotech (which will be very close to the same thing soon enough) are essen
Re:sweet deal (Score:2)
Willy says thanks (Score:2)
Re:Willy says thanks (Score:2)
Re:Willy says thanks (Score:2)
Yeah, right (Score:2)
Main benefit is low weight. (Score:2, Insightful)
Ouch. (Score:2, Funny)
"New Prophylactics Made with Titanium Foil"
and I said, "Ouch".
Naptime, it is.
Go apple! (Score:2)
D'oh! Please ignore this post - I just received a cease and desist letter for spreading rumours. (Despite the fact, of course, I'm typing this on my lovely Powerbook...)
solar schmolar -- CROPS are the real solar energy (Score:5, Interesting)
Why? There isn't enough energy in the sunlight to sustain the metabolic rate required for movement. In billions of years, nature hasn't figured out how to covert enough sunlight into energy to sustain an animal's movement other than by concentrating it first into vegetable matter which can be eaten.
For humans to make use of energy, we pretty much have to burn something. We have to release solar energy stored as food, then in most cases concentrated in the form of hydrocarbons.
Fission energy, fancy as it may be, is still about just making water hot. For that matter, if they get there, so will fusion energy be.
We humans are stunningly good at burning things and making excuses for the things we do that are essentially asocial. Aside from that, we're not exactly all that and a bag of chips.
There's no such thing as free energy. The trick we need to find is how to tap bigger forces. Tidal forces with tethered floating generators which rise and fall with the tides and capture that motion as energy would be good. Finding that so called vacume energy between particals would be a fairly useful trick as well.
Making giant solar panels which turn sunlight into energy at less efficiency than plants, then waste most of it in transmission and storage overhead is ultimately not going to win.
More near term, we need to find or engineer a crop which is ideally suited to concentrating sunlight into a hydrocarbon or sugar that can be stored, transported without sigificant loss, then burned.
Unless one of you
Re:solar schmolar -- CROPS are the real solar ener (Score:2, Interesting)
This is absolute bullcrap. There is more than plenty of energy in solar rays to power an animal. It is more convient, however, from the perspective of a moving entity to eat other things. If they do, they do
Re:solar schmolar -- CROPS are the real solar ener (Score:3, Informative)
Please carry on.
Re:solar schmolar -- CROPS are the real solar ener (Score:2, Interesting)
You said: "Fission energy, fancy as it may be, is still about just making water hot. For that matter, if they get there, so will fusion energy be."
That's true about fission. And although that's one obvious way to generate electricity from a fusion reactor, a lot of fusion research has also gone into magnetohydrodynamic generators. I won't try to explain them (because I can't; I don't really understand them myself) but google might be able to get you started if you're interested.
It was also mentioned
Re:solar schmolar -- CROPS are the real solar ener (Score:3, Interesting)
I agree with much of what you say. There's just a couple of things I want to comment on.
This suggestion isn't really viable. The problem is that electric power needs to be continuous, and electric energy can't really be stored in the quantities needed for widespread use. Because of this, the large surges of power an
Re:solar schmolar -- CROPS are the real solar ener (Score:3, Interesting)
I'm sorry, but this is nonsense. Most plants are about 15% efficient on a good day. Commercial solar panels are available with twice this efficiency and lab crystals with over 60% efficiency have been grown.
Even worse, current human energy usage is 400 times the carbon fixing ability of the biosphere. 400 times! At this sca
designed to be lightweight (Score:3, Interesting)
This device is designed for aeropsace applications; that is, it's a lightweight solar cell. At the bottom, there's a blurb about being able to supply electricity at commercially viable prices - but electricity is currently generated by oil, which is a volotile commodity, so it depends on how much oil-generated electricity "costs" on a given day.
Not too many years from now, oil demand will permanently outstrip supply - so when that happens, solar will probably become permanently economically viable. At which time, mass-production will drive down initial costs.
The issue of how long a given solar cell produces usefull power is also part of it - because if, over the life of the cell, it produces electricity of a given market value, above what it cost to make, then it's "economically viable" - therefore, of the three factors involved in determining "economic viability"
1. Initial cost to produce.
2. Longevity of the cell.
3. Market value of electricity over the life of the cell.
#1 is not the crucial variable. #2 also, really isn't a crucial variable. #3 IS. So if electricity is cheap, or if the cell doesn't last long (both of which are the current barriers to solar power being "economically viable") then it's not worth it.
When electricity becomes expensive (compared to today) - then solar power becomes more attractive.
Or, if some new type of solar cell becomes available that will have a useful lifespan of say, 50 years, instead of 20, that will make a difference. But the main factor is the cheapness of electricity. (some folks of the green persuasion might even say that electricity does not currently cost what it should, that there are many "hidden costs" - like funding wars to secure petroleum, ecological costs of the waste products, etc. - Kinda makes all this "free market" talk sound kinda silly.)
WTF? It is still Si (Score:2, Informative)
YMMV (Score:2)
1000W/kg? (Score:2)
It DOES use silicon (Score:4, Informative)
Their solar cells are made in a wafer fab and have no more than 15% efficiency, like everybody else's.
So this isn't the Great Solar Breakthrough. Sorry.
This is only the first step... (Score:3, Funny)
1. Replace titanium foil with tin foil (evidently cheaper)
2. Make hat out of it (for charging mobile devices)
3. In Soviet Russia, step 3 questions YOU !!!!!
4. Profit!
I'm a big solar booster, but... (Score:3, Informative)
...these guys are nothing special. Here's the deal:
88%+ of the world's solar panels are still cut crystals of mono - or poly - crystalline silicon. People know how to work it, they get a reliable if uninspiring 5 - 8% annual decrease in prices from it, and they've been able to ride it through quite a bit of market growth - up over 1200 MW in 2004, up from 750 the previous year, 400-some in 2002, etc. Good stuff.
The thin-film solar people have always made these claims that they're going to cut solar from $2.50 / Watt (mfg. cost) to like $1. And theoretically, there seems to be no reason they shouldn't. But their factories, which are always supposed to just run like printing presses or coated auto glass factories, always end up being much much more finicky and expensive and labor intensive than initial projections, and they end up - not with ridiculous costs, but right back in that $2 / Watt range. Hence the sub 5% market share.
DayStar's technology is not markedly different from any of the other thin-film silicon people (or thin-film CiGS or CiS or the other materials) - their big deal is that they have that superlight titanium foil. It does jack up their manufacturing costs hugely from using like a stainless steel (Uni-Solar) or a plastic / roofing material backer (Uni-Solar / Solar Integrated Technologies) or putting it into a normal framed module (First Solar, Shell Solar,) etc. And thier new little factory in NY there maxes out at I think 30 MW / year (2.5% of annual world production) So why would they do it?
Weight-conscious applications. It costs $10,000 per pound, still, to launch things into space, and people are honestly starting to look at airships again. Even though Boeing Spectrolab has essentially owned the high-value-add high efficiency to weight ratio solar market for a long time , there's still serious money to be had there - they may either settle for being a big player there, or, take DARPA money and use it to work the kinks out of their stuff for two, three years and go to market with a cheaper substrate and a roll-out roofing product, using much less silicon than a conventional process.
Re:Does not silicon? (Score:3, Funny)
Re:This has all been gone over before... (Score:2)
Great, then we'll have to listen to people bitch and whine about global warming caused by bunny farts and deal with the smell. In all seriousness, though, I agree 100%. We should be much, much more nuclear. Easy waste disposal problem: Just store it beneath the US Capitol building until a safe, effictive storgage facility is designed and constructed. You'd be AMAZED how quickly things can get done wi
Re:This has all been gone over before... (Score:4, Insightful)
You have to choose your evils. If you want to avoid radiation, fine, but don't complain when you have to deal with other forms of pollution to compensate for the energy-thirsty needs of modern society.
Re:This has all been gone over before... (Score:5, Insightful)
* Wind: Dead birds, intermittency in many areas, large surface areas, noise
Dead bird thing is mostly a myth. You will kill a thousand times more birds of prey by putting in a highway & getting them hit while munching on roadkill. Radio towers and bridges are just as dangerous as wind tubines to birds.
see http://www.homepower.com/files/birds.pdf
"Wind Generators and Birds: Power Politics?"
Large surface area: most wind farms are dual use, cows still munch the grass, only a small percent of land is lost to use, and that is mostly from access roads.
Noise: true for 1970's turbines. All new turbines are geared and rotate quite slowly. I've stood under one of the new 200' tall versions in 40mph winds.. you just hear a gentle swoosh. From a 1/4 mile away you don't hear it at all.
* Solar: Sigificant chemical wastes, large surface areas
just to note the really nasty galium arsenide solar cells are a tiny fraction (ie only NASA & similar use them). Most solar cells are made from recycled Si from the chipmaking process. That waste is already being made by computer chip makers; the solar cell manufacture process actually reduces existing industrial waste!
* Tidal: Beach erosion, corrosion of power units
Beach erosion? Please explain how dampening waves causes beach erosion? I just don't see it. Even if you unmix "tides" with "wind waves". Tide power is fairly hard to harness unless you live in an area of freak tidal range.
* Hydroelectric: Large loss of land, high greenhouse gas releases
The "high greenhouse gas releases" is a misleading arguement at best. Long and the short of it is that methane from anoxic lake sediment is not a net change to the carbon budget. Burning fossil fuels is.
see this comment for a fuller justification: http://science.slashdot.org/comments.pl?sid=14407
Re:This has all been gone over before... (Score:2, Interesting)
Re:This has all been gone over before... (Score:5, Interesting)
A quick Google search shows that on earth every square meter receives about 4.2kwh of energy per day over a 24 hour period. [ucsusa.org]
A quick look at my electric bill says I use about 20kwh/day as a rough average -- another Google search suggests that the average US household uses approximately 25kwh/day [hypertextbook.com]
...So, finishing the math: using 15% efficiency solar cells, the Average US Household needs only 40 square meters (430 square feet) of solar cells to cover all its energy needs. Heck, I could use 5% solar cells on my roof in downtown San Francisco, and STILL have 2x extra capacity to sell back to the grid!
Don't get me wrong: Solar won't solve everything, particularly in applications like transportation where energy storage is an issue --- and cheap Fission IS something we should have figured out a long time ago --- but please don't resort to misinformation to make your points, it only weakens what you are saying.
Re:This has all been gone over before... (Score:3, Insightful)
World power consumption is 13.94 trillion kWh.
Even if all of those cells were in production today, it would still fall short by a factor of about 500, if my calculations are correct. It would take more than a century to replace everything, and that's assuming an annual 25% growth in shipped capacity
Re:This has all been gone over before... (Score:2)
Over 200 times our current electrical power consumption strikes the Earth's surface. If we were to abandon all fossil fuels for mobile transport and powered them off electrical power, we'd have to generate more electricity, but we'd still have over 100 times the power we'd need striking the surface of the Earth. I'm not saying it would be practical to cover 2% of the surface of the Earth with power cells. But,
Re:This has all been gone over before... (Score:3, Informative)
Well, the amount of solar energy hitting us is around 1.5 kilowatts per square meter at our distance, that would be when the sun is directly overhead (and through the atmosphere). That drops off as a cos of the angle away from the point facing the sun. So if the sun passed directly overhead at noon, at 9:00 am and
Re:This has all been gone over before... (Score:5, Informative)
Don't confuse photoelectrics with photovoltaics.
For example, Sandia Labs has a plant currently in operation [sandia.gov] that produces 5MW in 9 acres, by focusing light onto a tower that heats molten salt which drives turbines. It can produce energy 24 hours a day.
The United States' generating capacity a few years ago was 813 gigawatts [geni.org], so at .55 MW per acre you'd need 1.4 million acres for all of the US's energy needs. That's about 2300 square miles or 6000 square kilometers, or about 1.5 Rhode Islands. We have many deserts that are larger than that.
Realistically, you don't need a power generation mechanism to be able to handle the entire United States energy needs before you put it in production. You just need it to be cheap (and cheap after the costs of fighting NIMBY lawsuits are factored in).
Sandia's web site doesn't say what their cost per megawatt hour is, but they do say the entire facility is currently worth $120 million. Since this type of system uses nothing exotic, I would expect economies of scale to change the numbers quite a bit. Assuming a life of 30 years, they'd have to be able to reduce the cost by about a factor of 10 to be competitive with today's rates. It could happen.
Re:This has all been gone over before... (Score:4, Informative)
But this Department of Energy page [energy.gov] does. They say such systems are currently at 9-12 cents/kWh, but expect 4-5 cents/kWh in a few decades. Which is certainly competitive.
Re:Ohhhhh, now I get it. (Score:2)
Limits: Cost vs. Cost-Ignoring Applications (Score:3, Interesting)
There are applications for which the efficiency mat