Talk:Solar energy/Archive 2

message: This sounds unlikely to me:-
"South-facing (for the Northern Hemisphere) or north-facing (for the Southern Hemisphere) windows with insulated glazing that has high ultraviolet transmittance."
Is there a reference or detailed reason?  Midgley 17:35, 24 March 2006 (UTC)
replies: text: If anything, you want NO glazing on your heating windows.  And yeah I think they meant IR -- we care about heat loss moving out after gaining heat from sunlight. 82.93.133.130 09:32, 30 November 2006 (UTC)
thread_title:  UV or IR transmittance for warming through windows? 

message: I removed the following sentence by User:68.126.200.157 "Costs about 8-12,000 dollars for a solar system to bre installed" Ignoring obvious grammar issues, I felt like this comment was not specific enough so it might be a little misleading. A solar water heater was installed recently in my home of the non-focusing type (passive collection type) and it cost much less than that. While we might not be talking about the same system at all, I think the sentence should identify what specific kind of non-focusing water heater system it quotes the price for. Second and more importantly, I think this type of information would be extremely useful to the article, especially if it were referenced with a price quote. If User:68.126.200.157 or someone else would like to look up the info for the various types of water heaters, this would enhance the article significantly. Sifaka 04:54, 30 March 2006 (UTC)
thread_title:  Price of non-focusing water heaters 

message: At this time, solar power is described as having "some" environmental costs.  Unless these can be quantified, the word will be changed to "minor".
:Actually, the other way would be more logical. Minor, compared to what? That needs quantification, unlike 'some', which is the proper neutral description .Jens Nielsen 15:04, 31 July 2006 (UTC)
replies: text:  "Some" can be interpreted as a little or a lot, which is far too broad.  Minor is more NPOV, unless you can provide evidence to the contrary. --Skyemoor 17:45, 31 July 2006 (UTC)
replies: text:  I assume we mean their costs come from manufacturing process (esp PV cells, all that water, heavy metals and silicone sawdust waste).  If we can find a manufacturing page, we'd probably get better info.  I'm looking... 82.93.133.130 09:35, 30 November 2006 (UTC)
thread_title:  Environmental Costs 

message: Solar is cost effective even in grid areas, such as is exemplified by their inclusion in illuminated roadside signs around the US and Europe.
:Fair enough, but the sentence starts with 'In situations where connection to the electricity grid is' (problematic). The road signs don't bear on that situation, so put it somewhere else please. It's a very minor market (cf. rooftop panels), so I don't see much need to include it on its own here I must say.Jens Nielsen 15:04, 31 July 2006 (UTC)
thread_title:  Effective Uses 

message: For backup power, there is a tremendous difference in bringing a coal plant online versus a natural gas generator, the latter being considered dispatchable.  Trying to lump them together is misleading and suggests POV.
:Can you suggest a source for this please?Jens Nielsen 15:04, 31 July 2006 (UTC)
replies: text:  Certainly.  --Skyemoor 15:37, 31 July 2006 (UTC)

text: That's highly misleading at best. Insolation is much lower at high latitudes, and it's no coincidence that you see little PV in Norway or Greenland, even in off-grid areas. It's not even close to compensated by lower temperatures.Jens Nielsen 15:04, 31 July 2006 (UTC)
replies: text:  My mistake, I was thinking high altitudes.--Skyemoor 15:37, 31 July 2006 (UTC)

text: True, but I wonder if it is not taking it too far to discuss the limitations of other technologies here. The fact remains that solar power is of limited use for transport purposes. It happens to share that limitation with coal and nuclear, but not with oil or liquid biofuels. The section is meant to be a brief overview, not an exhaustive discussion of all contingencies.Jens Nielsen 15:04, 31 July 2006 (UTC)
replies: text:  Since energy for transportation is being discussed, and solar is listed as having a disadvantage in this area, it only makes sense to provide context about what is being compared.--Skyemoor 15:37, 31 July 2006 (UTC)

text: And even using DC has losses anyways.  Esp if the power source is far from the load.  You also need quite a lot of copper : )  82.93.133.130 09:38, 30 November 2006 (UTC)
thread_title:  Cons 

message: Doesn't seem to fit with the rest of the article. Most people don't mean any of the power sources listed in this section when talking about solar power. A more approative article for this section would be renewable energy sources. Joncnunn 15:52, 21 April 2006 (UTC)
replies: text: Wikipedia is not paper . It can afford to give a full encyclopedic description of all energy sources that originate from the sun not just the narrow definition used by some.Lumos3 09:11, 27 April 2006 (UTC)
thread_title: Indirect solar power section

message: the system in the Mojave desert is said to be the world largest below, which one is bigger? -- 69.203.102.77 (moved by CyrilB 09:23, 1 May 2006 (UTC)
thread_title: question moved from the article

message: This image commentry says the map has "taken into account the cloud coverage available from weather satellites." Does this mean:-
* values have been marked down to levels which would be recieved taking into account the average cloud cover,
*or does it mean values have been marked up to levels they would attain if cloud cover had not been present?
Lumos3 19:56, 12 May 2006 (UTC)
replies: text: "take into account" could mean marking up or down. Ichanged the text to applying. Lumos3 09:24, 14 May 2006 (UTC)
thread_title:  Global solar energy resources Map is not clear 

message: One thing became clear after I put those external references in a list: there are quite a few references that may be viewed as commercialism. E.g. what I noted is several references to Stirling Energy Systems, in what appears to be blatant commercialism, but there are links to several other companies as well. I guess that's OK if those links it provide unbiased information, but it is not OK as it talks about "the largest" in apparent commercialism. Can somebody plow through all of this and clean it up? JdH 12:19, 14 May 2006 (UTC)
thread_title:  Commercialism? 

message: There are a number of references in this article, from several sections, to Solar hot water. I suggest that the information on Solar hot water be moved to that article, with a brief description and link from here. That will also help cut down this article and improve layout and clarity. 
Any objections? --Singkong2005 06:41, 5 June 2006 (UTC)
thread_title:  Solar hot water  

message: If DC was indeed the right choice for power distribution. Everything I CAN USE around me works on DC. Ofcourse the things I cannot use. like the govt grid which goes off and on every 2 days works on AC :-)
:You mean if AC was the right choice?  You can't distribute power with DC.  You lose way too much of it.  If you're making your own power at home, though, you have the possibility of using DC.  Review the War of the Currents (Tesla/Westinghouse vs Edison). 82.93.133.130 09:45, 30 November 2006 (UTC)
replies: text: Yes AC is able to be stepped up and down in voltage to suit our needs. It is much more efficent to have high voltage in the lines that take electricity long distances. But if we have high voltage in the home it is too dangerous to use. AC allows us to have both through the power of induction. 192.53.187.183 18:30, 21 March 2007 (UTC)
thread_title:  does make one wonder.. 

message: Photoelectrolysis of water has been researched off and on starting with Honda and his coworkers, and work continues today with Graetzel and many, many more. I have added some information under solar chemical in an attempt to fill this hole in the article. Perhaps others would like to add more along this line? Rhelmich 06:47, 21 June 2006 (UTC)
replies: text: I think you are the expert here, so it is up to you to research the subject and put in some more information. JdH 08:11, 21 June 2006 (UTC)
thread_title:  Photoelectrolysis of water 

message: I'd be curious to compare my electric costs with the rest of the world's. FWIW, I'm in Austin TX and am paying 9.5 US cents per KWh. At this price, I cannot amortize a photovoltaic system in less than 50 years (see here), and so am curious to see what the rest of the world is payig for grid electricity. linas 05:12, 22 July 2006 (UTC)
replies: text: In the UK 11.9 pence (22.34 US cents) per KwH decreasing to  8.24 pence (15.35 US cents) after the first 168 KwHs in each quarter-year. But our insolation is much less than yours. And with no net metering it is worth trying to use all the self-generated power in the house rather than exporting it to the grid. And considering how to use the heat absorbed into the panels. Itsmejudith 22:42, 28 July 2006 (UTC)

text: Have you included subsidies (also tax breaks and the like) in those costs? If so, that makes it hard to compare at any rate.Jens Nielsen 07:15, 29 July 2006 (UTC)

text: Writers to Home Power from California have listed daytime rates at 52 cents per kwh.  IN Michigan, it depends on your utility-- Consumers' is 7.9 cents and Great Lakes' is 9.something cents.  But unlike CA, MI doens't have net metering (very important to payback calcs) nor time-of-use (only for commercial/industrial customers).  Those two things need to be considered before doing any more calculations.  That aside, TX seems to have pretty cheap power, and if you want to go off-grid, consider that you're paying for a life-time's worth of power all up front.  In this case, you do solar for hippie or black-helicopters reasons :) 82.93.133.130 09:51, 30 November 2006 (UTC)
thread_title:  Sample worldwide electric costs 

message: I would on balance prefer the cleanup tag to remain in place until all the items on the to-do list have been addressed. There is rewriting currently in progress. Thanks.Itsmejudith 19:57, 24 July 2006 (UTC)
thread_title:  Cleanup tag 

message: No mention of limited lifetime of solar panels or effect on the local environment of large installations? — Omegatron 03:25, 4 August 2006 (UTC)
replies: text: Do you want to add these points, with sources for them? Thanks.Itsmejudith 07:21, 4 August 2006 (UTC)
thread_title:  Disadvantages 

message: I don't feel that this is an accessible section at the beginning of the article. The list of different technologies is in fact a de facto classification. So I propose moving the text currently in Classification to different sections. A section on Concentration would be appropriate, but Concentrating PV belongs in the Photovoltaics article. Any dissensions?Itsmejudith 11:43, 4 August 2006 (UTC)
thread_title:  Classification section 

message: I'm still not quite convinced by Mrshaba's arguments about the value of a classification section. (Although I very much hope this user stays and carries on making these helpful contributions to the article.) I would prefer to see the Active/Passive classification dimension merged with the Solar design in Architecture section. Concentration should be a section on its own. Direct vs indirect is a crucial distinction in my view and should be near the top of the article or could head the Types of Technologies section. 
I suggest that Deployment of Solar Power to grids is almost entirely about PV and should be moved to the Photovoltaics article. The exception is the solar furnace in France, which I don't think does relate to PV (I may be wrong), so that and the image could go into a section here on Concentration. 
I was also wondering whether Advantages and Disadvantages could go later, after the technologies have been described. But I don't have a strong view on it. Itsmejudith 21:42, 6 August 2006 (UTC)
replies: text: Thanks Lumos 3. I take your points and very much agree that all technologies should be in there and that it should not try to sell solar power. But does there have to be a Categorisation section? It just seems to me to be rather complicated for a casual user to have to understand that there are different ways of categorising the technologies before going onto the details of the different techologies. The individual technologies are either very simple, e.g. solar cooker, or refer to other articles. I am bearing in mind the issues in the To Do list, which complained of the muddling of different technologies. If there is a Categorisation section, what should it include? Itsmejudith 12:41, 7 August 2006 (UTC)

text: Agree that this looks better. I'll move the Deployment to Photovoltaics, except for the Solar Furnace and its image, which I think belongs in the Concentrating section here. Itsmejudith 16:28, 7 August 2006 (UTC)
thread_title: Ordering of sections

message: Lumos3... Good catch on the biomass vs. vegetation distinction.  Bad edit on my part.  The lightmill example is not a direct conversion though.  Photons don't move the vanes. Photons heat gases which move the vanes while trying to find a low pressure zone.  This is an indirect phenomenon.  The light mill article explains this.  I'll admit that the light mill is an interesting device but I don't think it belongs in either the direct or indirect examples of solar power or solar energy.Mrshaba
:You could use the same desconstruction to argue that any device is not actually catching solar energy , eg they just move electrons around, make molecules vibrate etc. The fact is that although the light mill is just a toy (today) it represents a visible and dramatic demonstration of solar power. The article should not just be limited to those technologies which are practical but should give the reader a view of the whole field. Lumos3 09:02, 8 August 2006 (UTC)
replies: text: The classifications direct and indirect are human defined ones. All those defined as indirect follow a tortuous path of energy conversion and storage in intermediate forms. Both the light mill and solar tower convert energy in real time and so are direct devices. Your analysis depends on detailed knowledge of the micro processes involved and cannot easily be applied except by phyics experts. To say the Crookes radiometer is indirect but the Nichols radiometer is direct adds nothing to anyones understanding of the subject. They are both real time energy converters and both are direct. Lumos3 22:26, 9 August 2006 (UTC)
replies: text: I think most people would call the lightmill "solar powered" and should at least stay mentioned here.  If you're going to keep solar water heating with glycol and a heat exchanger, why not the mill?  My 2 cents 82.93.133.130 10:04, 30 November 2006 (UTC)
thread_title: Direct and Indirect

message: The solar fiber technology is a sub-category of PV (thin film/dye). Can we move it over to PV?
I think we should also move the concentrating PV technology into the PV section. Opinions?  I can see the PV section isn't broken down into sub categories but it should be eventually to cover the various ideas out there.  We've already moved a lot of material into other sections.  I think this material should be moved too.  I'll wait a few days and then make an attempt at sliding things around.
As I see it, solar technologies break down basically into PV, thermal, chemical and lighting.  I will be working on grouping/tiering the technologies along these lines. User:Mrshaba
:Sound reasonable to me. Skyemoor 21:11, 22 August 2006 (UTC)
thread_title: Types of Technologies

message: Moved CPV to Solar Cell article. I'd like to link to this material in the Concentrating/Non-concentration section. User:Mrshaba
Reworked the Concentrating vs. Non-concentrating material.  Took some of the former choppiness out(maybe not).  The material (tracking types, solar thermal) was better covered under the individual sections so I replaced the redundant material with pointers to these sections.  Is there a way to put in a pointer to a specific section within an article? The solar thermal wiki article mentions a stagnation temperature of 220 C but 200 C is the number I keep finding so I used it.  I know the highest temperature possible for concentrating solar is the temperature of the sun's surface but I haven't been able to find what temperatures the concentrating power plants typically run at.Mrshaba
: Example: Talk:Solar power#Concentrating vs. Non-concentrating links to this section as in this example. (I think you can eliminate the part to the left of # for in-article links) - Leonard G. 02:07, 24 August 2006 (UTC)
thread_title: Concentrating vs. Non-concentrating

message: It would be helful to explain the difference between diffused and direct sunlight.  I looked around for a Wiki-topic that explained the distinction between the two but Sunlight didn't cover this subject.  This could be an area for confusion considering direct/indirect solar technologies.  I think an expanding description of sunlight as it relates to solar power could be helpful at the beginning of this article.  This link has a helpful image explaining reflection and absorption of sunlight by clouds and the atmosphere.  Reflection and absorption would tie in well with an explanation of diffused/direct sunlight. http://marine.rutgers.edu/mrs/education/class/yuri/erb.html 
Direct sunlight comes in a straight path from the sun.  Diffuse sunlight can be reflected off of clouds, landscape features, etc, as well as ultraviolet radiation that follows a scattered path to Earth's surface (that's why the sky appears blue). Some solar panels exceed their direct sunlight ratings (mostly due to reflections off clouds) and can overwhelm or damage a DC/AC inverter that is sized to the array's sticker rating. Diffuse_sky_radiation Skyemoor 22:47, 24 August 2006 (UTC)
thread_title: Energy from the Sun

message: I wrote this section a while back while the article was undergoing a consolidation process.  After reviewing this link I decided I did not do a good job with my classifications.  
http://www.eere.energy.gov/RE/solar_hotwater.html
The classification of solar water heaters is involved and I think it belongs within the solar hot water article.  I think we should use a few solar hot water representative examples but not present the material as if it is a classification of all the solar hot water technologies. Mrshaba 05:45, 31 August 2006 (UTC)
thread_title: Solar Heating Systems

message: The addition of line and point focus collectors is very good, though it seems it should belong in the solar collectors article so that we can reference it here.  Thoughts? Skyemoor 00:20, 12 September 2006 (UTC)
thread_title:  Solar collector types 

message: I'm concerned that this paragraph leaps from a general discussion of insolation (which is relevant to all types of solar power) into the conversion rates of photovoltaics. This relates to a problem with the article which is now mainly cleared up: that it used to mix PV and solar thermal in a way that was confusing for the reader. Does anyone have views about whether some of the material in this paragraph could be taken out of here and into photovoltaics? Should that include the map with the black dots? Itsmejudith 15:36, 1 November 2006 (UTC)
thread_title:  Para 2 of Energy from the Sun 

message: There is a contradiction between the diagram of available solar power, and what it says on the text. In the text it says more than a 1000 W/m2 reach the Earth's upper atmosphere. In the diagram, it shows 400 W/m2. Can there be some clarification?
There is 1000W/m2 reaching a flat disk facing the Sun, but at least half of this is lost due to night time, and then a whole lot is lost due to cloud reflection and atmospheric haze.  If you don't get the full 400W/m2 at a location, it's because clouds are in the way casting a shadow, plus some other similar factors.Sillybilly 16:40, 13 November 2006 (UTC)
thread_title:  Confusion with the Diagram and the Text 

message: I added a section on the quantity/quality paradox of soalr energy, and an external link to a more detailed discussion.  The "dimming issue ' is interesting and important, but not deserving of so much space in an overview article such as this.KonaScout 15:23, 24 November 2006 (UTC)
thread_title:  quantiy/quality 

message: Am I the only one who finds this section contentious? Perhaps the figures for conversion to biomass are accurate. But this is only a small part of the picture. In relation to consumption of energy in buildings, a basic fact is that each building receives far more solar energy per year than its heating/cooling load. So in temperate climates the problem is not so much how to heat the building as how to conserve heat. In warmer climates the problem is how to use the energy for cooling. We are awash with solar energy and sometimes it is the simplest technologies, like the solar cooker, that use it most effectively. Itsmejudith 20:38, 24 November 2006 (UTC)
replies: text: The diffuse nature of solar energy means that a substantial and expensive material scaffold must often be constructed to collect, concentrate, transform solar energy, and deliver it at a sufficient rate to make it useful in industrial society. Your blanket statement "each building receives far more solar energy per year than its heating/cooling load" is not universal--it certainly is not true for larger commercial buildings and factories.   KonaScout 17:53, 25 November 2006 (UTC)
thread_title:  Quantity-quality paradox section 

message: This article makes use of non metric/SI units such as BTU and the mile. At the very least there should be an SI equivilant listed. Since this is a science/engineering article, I think it would make sense to use SI units exclusively.  Harley peters 16:00, 6 December 2006 (UTC)
thread_title:  Units 

message: The article says
: "The potential energy in the winds that blow across the United States each year could produce..."
Isn't that kinetic energy? Molinari 08:25, 18 December 2006 (UTC)
replies: text: You’re right. I believe it meant to say this is the potential if fully expoited not potential energy in a physics sense. I've removed the word as it added nothing to the sentence .  Lumos3 12:15, 18 December 2006 (UTC)
thread_title:  Question about phrasing 

message: The page became unprotected today and the graffiti has resumed.  The protection was working and now that it's gone we're back to eliminating garbage from a page that needs a lot more thought put into it.  Please bring back the protected status.  I don't know who to send this request to so I'm putting it here. Mrshaba 01:51, 3 January 2007 (UTC)
thread_title:  This page needs protection 

message: I placed a request for citation at one point in the article.  The citation that it referred to was, I believe, http://www.antandsons.com/takesalook/solarpowerenergystocks_011206/ part of which says that gasoline prices are believed to hit $3 a gallon "by the end of the year" by which they meant 2006.  According to http://www.eia.doe.gov/oil_gas/petroleum/data_publications/wrgp/mogas_home_page.html gasoline prices were approximately $2.334 (depends on the state).  The citation should be updated with new information. 200.121.111.113 17:07, 18 January 2007 (UTC)
thread_title:  Requesting Citation 

message: In the section "Availability of Solar Energy", it is mentioned that "Annual photosynthesis by the vegetation in the United States is 50 billion GJ" and "The land area of the lower 48 United States intercepts 50 trillion GJ per year"; meaning that the average plant coverage of the US absorbs 1/1000 of the available energy ("Plants, on average, capture 0.1% of the solar energy reaching the Earth").  However it is then stated that "the energy absorbed per unit area is 6.1 GJ per square meter per year" (close -- the math using these figures says 6.25GJ/m^2/y) and therefore "This results in potential biomass production of 6,100 GJ per square kilometer per year."  This last sentence I take issue with, because it presumes that "potential biomass production" occurs at the 1/1000 (0.1%) rate previously attributed to average plant coverage (6.1GJ * 1,000,000m/km / 1000 = 6,100GJ).  I am certainly no expert in biomass production but as an interested reader I would assume that any land used for biomass production would have a much higher than average plant cover.  If this is not in fact a mistake then a link to a source explaining the relation between average and potential plant cover would be helpful. --66.189.113.164 15:34, 2 March 2007 (UTC)
thread_title:  Possible math error in biomass comparison 

message: the first solar powered cell phone is on the market —The preceding unsigned comment was added by Yeahsoo (talk • contribs) 23:32, 11 May 2007 (UTC)
thread_title:  the first solar powered cell phone