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I can't think of any rare earth elements that go into PV production. I wonder if you mean non-earth abundant minerals. Rare earths, like Neodymium, are however incredibly important for wind power generation as those require strong permanent magnets.
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Sep 4, 2012 08:23
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Hobo Erotica posted:I've got Cadmium, Tellurium, Gallium, Arsenic, Indium, Selenium, Silane gas, etc. To be honest though I'm not a geochemist so if they're not rare earth elements then I apologise. None of those are rare earth elements. There is a lot of work into producing PV cells that don't require non-earth abundant and less toxic materials like those you listed above and in fact the most common solar cells available today, poly-crystaline silicon cells use none of them.
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Sep 4, 2012 08:41
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QuarkJets posted:The downsides are that you need some pretty uncommon elements to make PV panels. That's only pretty much only true for PV technologies that you can't buy today.
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Sep 5, 2012 07:46
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QuarkJets posted:Is it? I'd love to know more, what's usually used to make PV panels today? By far the most common solar cells on the market today are single crystalline and polycrystalline silicon. These are pretty high efficiency cells but they are also relatively expensive because it requires a ton of energy to melt silicon. They are basically made from only silicon and aluminum, which are the #1 and 2 most abundant elements in the crust. There are a number of emerging technologies like thin film CIGS (Copper indium gallium selenide), Cadmium Telluride, and Gallium Arsenide PV which use compounds that could be in shortage if they were to be upscaled to be a significant percentage of total energy production. Although these look very promising there is also emerging technology to more cheaply make silicon cells like ion implantation lift off processes that would greatly reduce their cost. Also there is a lot of research into making thin film solar with earth abundant materials. tl;dr. Earth abundance is very important to think about but it is by no means a show stopper in PV. Edit: Here's the current solar production stack. By far most of what's produced today is silicon although there are some new non-silicon technologies emerging in the market. Most notably is the CdTe production by first solar at the bottom. This is exciting but these less-earth-abundant technologies are not axiomatically the future of solar. 
Bip Roberts fucked around with this message at 08:03 on Sep 5, 2012 |
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Sep 5, 2012 07:56
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It's a big concern, it's just not at all the current holdup to adoption. I was objecting to the phrasing "you need some pretty uncommon elements to make PV panels", which is false. Efficient PV doesn't necessarily need rare materials. It, however, might very well be a problem later if a non-earth-abundant technology proves to be way more cost efficient than the field.
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Sep 5, 2012 08:14
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marmot25 posted:It's currently sequestered carbon that we will be releasing into the atmosphere, and unless we're planning to do some fancy sequestration when we burn it it's a bad idea. From a warming perspective I suppose it's better that we burn it first, given that methane has a stronger greenhouse gas effect, but it's still pretty bad. The true catastrophe scenario is that the oceans warm enough to the cause wholesale release of these deposits. I just think it's interesting that we'd consider their slow release acceptable. Aren't all fossil fuels sequestered carbon that'll be released into the atmosphere? At least with methane you get a better energy to CO2 released ratio. I agree that methane leakage and catastrophic release are very large concerns here.
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Sep 11, 2012 09:17
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Alkydere posted:Biomass There's been a ton of research into producing energy from biomass. The huge problem all of this has is that producing energy from very low energy density materials is that the total energy produced has to compete with the amount of energy it takes to harvest and ship to a power plant. In the case of something like corn ethanol production you get less energy out than it takes to produce it.
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Feb 28, 2013 01:09
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Install Gentoo posted:The sun isn't there at night, and we haven't gotten good solutions to actually store our solar energy yet. You don't need solar to be stored at night in large as demand is higher during the day. Solar has a very nice overlap with usage which is a big selling point. Baseline demand at night can be picked up by sources that cannot be modulated easily like nuclear or coal but solar is a very useful part of a grid. Storage is only a big concern for an all solar grid, not for a grid with some solar.
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Apr 1, 2013 06:04
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Yeah, concentrated solar is almost always better for efficiency but carries the huge issue that your module needs to track the sun.
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Apr 23, 2013 23:42
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Deteriorata posted:Over-building renewable generating capacity isn't necessarily a waste of money. The excess capacity could always be used to make hydrogen from water when favorable conditions result in more generation than is needed. Excess energy can also be put into things like Aluminum production, especially if the plants work off peak hours.
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May 8, 2013 18:43
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Deteriorata posted:Well, they don't really say what the technology is, but they describe it as a scrubber. Their presentation doesn't say they eliminate carbon dioxide, only carbon monoxide. They say the CO2 is removed in a later scrubbing step. In fact, their test results on slide 3 shows CO2 emission going up from 6.0% to 8.0%. quote:What is HydroNano Gas? Nope it's a scam.
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Aug 2, 2013 19:51
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CommieGIR posted:Overflight might be an issue. Why would that matter? The sun isn't focused on some point up in the sky and temporarily blocking a solar thermal plant won't cause a drop in output. Install Windows posted:And you don't see why demolishing an entire ecosystem and its native species might be a bad thing? Which method of power generation has no environmental footprint?
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Sep 27, 2013 03:29
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Install Windows posted:And this is before considering the enviromental footprint of the neccesary energy storage facilities so that there's power at night. You don't necessarily need storage. Solar is peak generation and unless you have an only solar grid you would use nuclear or coal for baseline generation.
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Sep 27, 2013 03:47
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computer parts posted:I was thinking more rare earths. There are no rare earths metals used in any current photovoltaic technology. The OP is wrong, I told them to edit it.
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Sep 28, 2013 19:40
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CommieGIR posted:....um, source? Only last year were they announcing new solar panels that use LESS rare earth metals, not NO rare earth metals. Here's a chart of basically all the solar materials listed with analysis on the scalability of the technology based on earth abundance. Although many of the materials such as Tellurium are not earth abundant none are rare earth metals.  Cyrus Wadia, Paul Alivisatos, Daniel Kammen, Enviromental Science & Technology 43, 2072-2077 (2009)
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Sep 28, 2013 19:53
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CommieGIR posted:Okay, thanks for the source, I was not around for the previous discussion. I guess for the overview, the use of earth abundant materials is extremely important in evaluating new solar materials. It's also a huge drawback from the current CdTe cells that are made. Nevertheless, by far the bulk of production and efficiency leaders come from silicon cells where there is no earth abundance problems at all. The availability of rare earth metals (neodymium, samarium) is a big issue for wind power which requires powerful permanent magnets that can withstand high heat.
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Sep 28, 2013 20:44
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Paper Mac posted:Is the relative abundance of construction materials actually a more important consideration than overall embodied energy and lifecycle? Not at all at the production levels most photovoltaics are currently being produced. If photovoltaic cells went in to mass production to the scale that they were a major piece in the energy equation many of the thin film technologies would have a hard (or impossible) time scaling up. The chart I posted earlier shows for a number of materials what the limits on power production are based on the current stockpiles of a resource and the maximum mineable availability of a resource. Bip Roberts fucked around with this message at 23:05 on Sep 28, 2013 |
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Sep 28, 2013 23:03
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CommieGIR posted:
Did they include the words "good sunshine day" as a joke about Germany's weather?
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Dec 13, 2013 01:29
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Hedera Helix posted:Hey! I like how they look. I think the most robust method of energy storage is pumping water uphill. It's not a very efficient way of storing energy. Also you don't need to store solar energy because it's usually peak generation and you have all sorts of other generation that can't be turned off at night like coal and nuclear power that make energy at night virtually free. There are a whole bunch of proposed methods like pressurized caves, hot salt banks, flywheels, banks of batteries and super capacitors but none are that robust of technologies.
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Jan 10, 2014 06:26
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RDevz posted:Unfortunately, peak demand doesn't correspond to times of peak solar generation - if you take the UK, you're going to see annual peak demand between 16:00 and 18:00 on winter evenings, when it's either twilight or just plain dark outside (source). Total solar generation at that point is zero. I got bad news for you if you want to use solar power for anything in the UK.
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Jan 10, 2014 09:49
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I would guess that you could find a number of well respected physicists who think that Fusion power is a tractable problem. I would guess the number of biologists who think leathery bat wings is the future of mankind is much smaller.
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Feb 14, 2014 05:45
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Solkanar512 posted:I'm still waiting for an answer on this. What do major environmentalists groups expect us to do for baseload power generation that doesn't contribute to our carbon problem? Nothing's more environmentally friendly than hydroelectric power.
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Jun 18, 2014 14:10
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140,000 tons doesn't seem like a huge amount of plastic. That's like and aircraft carrier and a half of plastic, which is a lot, but not necessarily on a global scale.
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Jul 7, 2014 02:10
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Sheikh Djibouti posted:If I may, I have a technical (or perhaps production related) question. Back in the early 90s, there was talk about, and development of, thin film silicon photovoltaic technologies, with the notion that transparent or semitransparent photovoltaic films could be used in building integrated applications, for example coatings on exterior glass surfaces. The technology still appears to be around, but I can't seem to find anything on why it isn't more widespread. Problems with efficiencies? Photodegradation? Not commercially viable at current production volumes based on energy yield? It exists and has rather nice efficiency but why build it into the exterior of your building when that's fundamentally a pretty dumb place to put your solar cell. Technology like CIGS and CdTe have very nice power/price ratios comparative to silicon but using your solar cell as a cosmetic feature on your building is stupid.
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Jul 10, 2014 02:42
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Sheikh Djibouti posted:I think the idea was that you wouldn't be limited to discrete cells on the roof but could, in essence, convert your entire glass envelope into a generating substrate while retaining transparency. Yeah, you probably don't want to invest quite expensive solar cells to strap to the side of your building where they will work half as well, require you to cut down all your trees and be pretty ugly to boot.
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Jul 10, 2014 02:54
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Hedera Helix posted:I vaguely recall reading about instances where colored filters above a thin-film panel would concentrate light on it, bolstering its ability to produce power. Would this actually work, or would the filters reduce the amount of light actually reaching the panel? You're probably thinking of luminescent concentrators which are a rather nice technology in that they can be developed orthogonally to PV semiconductor technologies. They also can make rather nice gains in efficiencies for certain materials.
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Jul 10, 2014 04:13
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LemonDrizzle posted:Is there any non-dangerous way of storing energy on a grid scale? Nature stored it for us in the form of clean burning uranium.
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Jul 11, 2014 20:33
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A bigger problem is it's basically impossible to build more transmission lines (in the US at least) because of the property rights necessary to get right-of-way for them.
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Jul 16, 2014 15:49
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EoRaptor posted:So MIT just announced this, a carbon foam and graphite floating layer that can transfer solar energy to water in a reasonably efficient manner. Any solar-thermal installation uses concentration and steam is transparent to visible light. It would be very dark out if water absorbed the visible. Bip Roberts fucked around with this message at 16:30 on Jul 22, 2014 |
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Jul 22, 2014 16:27
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When they say "consume" water what do they mean. Does drawing water from a river and returning it warmer count as "consume" or is this suppose to portray that water is drawn up and deposited into a black hole?
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Aug 6, 2014 19:32
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Rent-A-Cop posted:So roughly how big a hunk of Plutonium would I need to get a decent amount of horsepower out of an RTG? So according to wikipedia "one gram of plutonium-238 generates approximately 0.5 watts of thermal power." so at 750 watts and ~20% thermoelectric efficiency it's ~7.5 kg/HP. Also you need a heatsink that can dissipate the 3.5 kW, so if you want to heat something at the same time it's just dandy. Bip Roberts fucked around with this message at 23:15 on Jan 6, 2015 |
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Jan 6, 2015 23:12
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