Talk:Solar energy/Archive 5

This is an archive of past discussions about Solar energy. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page.

Archive 1

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Archive 3

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Apples and Oranges

I have mentioned symmetrical vs, asymmetrical arguments on this talk page. These are more commonly understood as apples to oranges comparison. The page should try to consistently compare apples to apples and oranges to oranges... I did some rework on the Architectural section tonight and I've noticed some A to O comparison conflicts. The page is far from complete but I just want to shout out a warning against apples to oranges comparisons... We should bring them up and resolve them where possible. Mrshaba (talk) 09:15, 23 November 2007 (UTC)

Pictures!!!

I found a bunch of great pictures on Sandia's data base last week and am uploading today. How do I tag these with a category? Is that something I do from Wikipedia commons? Mrshaba (talk) 20:18, 23 November 2007 (UTC)

After you upload each photo, edit the file on commons and add at the bottom, [[Category:Solar energy]]. You can also put it in while you are uploading it but then it will probably not come at the end of the page. 199.125.109.129 (talk) 00:19, 24 November 2007 (UTC)

Explanation why I removed the following section

Ammonia can be decomposed into nitrogen and hydrogen at high temperatures (650-700 °C), and the stored gases can be recombined to generate heat or electricity via a fuel cell. A prototype system was constructed at the Australian National University.^[1]^[2]

Now why would anyone want to decompose ammonia in a solar power station? If anything, you'd want to make ammonia, either as a fertilizer, or as a hydrogen storage option. The actual article says that the nitrogen hydrogen reaction to get ammonia is exothermic, and can drive a steam generator, while the decomposition reaction is endothermic. Basically ammonia is supposed to be an intermediate storage medium, for 24 hr production, a storage device. Their storage device is a mixed liquid ammonia/gaseous hydrogen nitrogen vessel. Now picture you want to accumulate a lot of energy and store it with this system, even for months. That means you break down a lot of the liquid ammonia and turn it into a gas. Imagine the pressures you generate - a gas is the worst way to store energy, you might as well go ahead and break down water and store the hydrogen into gigantic citysize balloons. If anything you want an energy storage system that's the other way around, a liquid representing your high energy "fat", and preferably a liquid representing your low energy waste that can be regenerated into the "fat." Molten salts are such things, unfortunately they are thermal energy storages, you'd prefer chemical means of storage that are not limited by Carnot Cycle thermodynamic efficiency limits. And if you want a medium that's for a few minutes only, before you convert the energy into a permanent storage medium, you're better off with either straight hydrogen, or the noble gases: helium, argon, xenon, that allow you to take the temperature very high (over 2000°C) and drive a very efficient thermal engine that generates the electricity that generates the chemical solids or liquids storing energy. If anything, you want to not consume but generate ammonia with a solar station, from atmospheric nitrogen and water derived hydrogen, because liquid ammonia is a relatively easy to handle hydrogen carrier, and a much needed fertilizer. Ammonia production still uses a lot of energy, because it requires very high pressures, hydrogen, and air separation. Sillybilly (talk) 00:11, 20 November 2007 (UTC)

I have no problem with your removal of this information. I think this section should be about using solar energy in chemical processes. The process you removed isn't particularly notable in my opinion. As far as solar chemical goes... I noticed Judith moved the photosynthesis blurb that was at the bottom of the section up to the top. She blended the info well and the movement of the information goes along with the way the article is laid out in general so I think this was a good regrouping. One concern I have is where to add additional solar biological info. I've been wondering where to re-place interesting history of medieval crop growing practices in the article. Should this be a separate Solar biological section or could we place some info within the Solar chemical section. Any opinions? 66.122.77.148 (talk) 06:41, 20 November 2007 (UTC)

You're right. It's a very nicely written and interesting section but somehow it doesn't belong under solar chemical. I would just split it out from under the chemical subsection (it's listed as a subtopic where the titles are uptop), and rename the agriculture-horticulture title to something more generic along the lines of "solar biological."Sillybilly (talk) 00:52, 24 November 2007 (UTC)

I don't see a problem with Solar biological standing as a separate section. I've tried to keep the main sections organized by principle energy conversion and energy use. i.e. light used as light, light to heat, light to chemical etc. The Architecture and urban planning and Solar vehicle sections are exceptions to this rule. I could have grouped Solar vehicles under solar power but I figured because Transportation has its own category of energy use (Commercial, Industrial, Transportation) it deserved a stand alone section. Solar biological covers all agriculture if we want it to but I don't want it to. I see this section as listing techniques to "optimize" energy use in agriculture. I've only touched the surface of these. I'll look for more notable examples of solar energy optimization in agriculture. Mrshaba (talk) 01:57, 24 November 2007 (UTC)

Solar energy glossary

I've started work on a solar energy glossary. I figure we can pull the active,passive,direct,indirect definitions there and replace them them with an introductory blurb about how solar technologies deliver a diverse range of energy types (heat, light, electricity, chemical). Big picture stuff like how solar energy can be used to offset or replace conventional energy use. Mention that solar energy is often turned to when conventional energy supplies dwindle. The Greek example of turning to solar architecture when firewood got scarce is a good candidate. This example could be balanced against a modern example... German/Japan come to mind. Any thoughts on pulling these definitions out? There was a time when I really thought they needed to be there but now I think this info is better put in a Solar glossary. 70.135.164.15 (talk) 21:11, 24 November 2007 (UTC)

Picture changes

Pictures in the lead and throughout the page should remain an active topic. I like experimenting with pictures because it's a quick edit. Bing bang... I've thrown a bunch of sun pictures above for consideration. I found a treasure trove of open source solar technology pictures at Sandia so I'll be throwing those in for consideration too. I might finally figure out how to upload images seamlessly. Well see... I'd like the picture debate to be active. We should express our impressions of the pictures honestly: I like, I don't like, Clear, Confusing, Striking, Makes the point, etc. We should include caption ideas where possible. We should figure out which pictures on the page need improving and find pictures that can easily be alternates for existing pics? We should line all the pictures up on a sub-page and work out the plan there.

The box saga. 80% are in favor of removing the boxes due to several issues so I took the boxes out again. If Anon brings the boxes back I'll take it to WP:I like it for further resolution. Mrshaba 18:50, 13 November 2007 (UTC)

As I said before, the only people who don't like it are the few people who like nuclear power. They apparently don't like being shown that nuclear power isn't needed. Almost everyone I showed it to said they did like it. Try it yourself. 199.125.109.129 01:48, 14 November 2007 (UTC)

The notion that the people who don't like the box graphic are those who favor nuclear power is beyond nonsensical. My objection is not to the content, but to the appearance. The "artwork" is primitive, unimaginative, and unappealing. It does nothing to draw a reader into the text; in fact, it creates an impression of amateurism, which is unfair to those who have invested so much time and effort in being thorough, scientific and objective. --NameThatWorks (talk) 17:37, 26 November 2007 (UTC)

And just to prove a point, what is your answer to the question, in order to meet our energy needs for the next 50 years, should we develop solar power or nuclear power? Of those two, solar only, nuclear only, both, or neither?

199.125.109.38 (talk) 14:50, 27 November 2007 (UTC)

They both need to be developed, but that proves nothing in regard to why I object to that hideous graphic. Anyone who walks upright knows the sun puts out much more radiant energy than civilization requires. Again . . . it isn't the information, it's the presentation. --NameThatWorks (talk) 22:07, 27 November 2007 (UTC)

Well so far you have continued to prove that only people who think that nuclear power should be developed don't like the diagram. If you don't like the diagram I suggest that you replace it with one that has three other objects instead of cubes. Globes won't work, it just makes it look like a diagram of the solar system. Windmills, oil derricks, elephants, draft horses? I am open to suggestions, but so far no one has come up with a better presentation. 199.125.109.104 (talk) 04:49, 28 November 2007 (UTC)

Requesting a third opinion might be helpful in this case. Also, I'd like to see some Physics project members contribute to these discussions. Itsmejudith (talk) 14:36, 17 November 2007 (UTC)

Let's get a third opinion. Mrshaba (talk) 17:35, 20 November 2007 (UTC)

In the words

In the words of the first century Roman architect Vitruvius: and then we change the "quotation". Is there a better phrase that conveys the idea that the following passage is more-or-less what Vitruvius would have written if he had written in English? --Wtshymanski (talk) 23:47, 29 November 2007 (UTC)

I don't understand. Do you find the "in the words of" phrasing too informal? I did not change the quotation, I used the translation that Perlin offered in A Golden Thread. Here's another one.

ON CLIMATE AS DETERMINING THE STYLE OF THE HOUSE

1. If our designs for private houses are to be correct, we must at the outset take note of the countries and climates in which they are built. One style of house seems appropriate to build in Egypt, another in Spain, a different kind in Pontus, one still different in Rome, and so on with lands and countries of other characteristics. This is because one part of the earth is directly under the sun's course, another is far away from it, while another lies midway between these two. Hence, as the position of the heaven with regard to a given tract on the earth leads naturally to different characteristics, owing to the inclination of the circle of the zodiac and the course of the sun, it is obvious that designs for houses ought similarly to conform to the nature of the country and to diversities of climate. Mrshaba (talk) 02:34, 30 November 2007 (UTC)

RFC pictures

Fixed RFCxxx template, set template section param to match discussion page section heading for section template is included in. DMcMPO11AAUK/Talk/Contribs 03:08, 26 October 2007 (UTC)

This is a request for input on the pictures to be used at the top of the page.

Current and former pictures

Image:SolarStirlingEngine.jpg

Nice "collection of solar energy" picture. --SmokeyJoe 21:42, 22 October 2007 (UTC)

Agreed. This is a decent example of a solar power technology. Mrshaba 23:09, 22 October 2007 (UTC)

Image:Available Energy-2.jpg

Boring graphic, requires too much study to work it out. Not worth its space. The point would be better simply made in a sentence. --SmokeyJoe 21:42, 22 October 2007 (UTC)

Agreed. Poor use of space. Mrshaba 23:09, 22 October 2007 (UTC)

Not true. There is no way that saying something has as much impact as a graphical illustration. 199.125.109.124 02:17, 23 October 2007 (UTC)

The information conveyed by this graphic is already text-based. The graphic elements rely too much on data that is mostly hidden from view (the implied volumes). With so few items that represent such truly large differences it would be better to elegantly state the contrast in text rather than using a graphic. --Cheng Houston 01:41, 29 October 2007 (UTC)

Someone with graphics skills could take the boring full-sun picture from below (or download a similar one) and superimpose a pie chart on the solar disc to illustrate these data. These isometric cubes are primitive, hard to decipher, and take up too much space. --NameThatWorks 15:30, 29 October 2007 (UTC)

A pie chart would be useless as each section would only be a very thin line. The existing illustration is a brilliant way to show a very large ratio by making the ratio into a cube, which shows the ratio to the third power of the dimension - a cube with dimensions ten times as big has a thousand times the volume, as such the huge ratios are very succinctly shown. Since the images are thumbnails they also don't take up much space but can be clicked on if anyone wants to see closer. I didn't create the image, but I do see how brilliant it is, especially making the larger cube the same color as the sun. 199.125.109.87 06:57, 30 October 2007 (UTC)

I disagree. A pie chart could show the same ratios in its three sections, as long as it was clear that the intent is simply to show the relationship among the proportions and not to add up to 100% of anything. Jeez, at least use perspective cubes and not those isometric jobs that only an engineer could love. --NameThatWorks 16:56, 30 October 2007 (UTC)

The average viewer will glance at the cubes and get an impression that there is a difference, but not the huge difference intended by the volumes. They will grasp the 2D differences not the implied 3D differences. The average reader is not likely to spend time performing mental gymnastics to work it out. Unfortunately the use of a pie chart is also forced. Due to the vast differences in quantities being contrasted either the pie would have to "lie" to accommodate incorrectly large sections just so they can be seen. Try creating a quick graphic in Calc, Excel, etc with the values presented. It will be obvious that a pie chart isn't a good choice. A simple table would present the contrast better than a graphic.Cheng Houston —Preceding comment was added at 02:33, 31 October 2007 (UTC)

All that the graphic needs to do is give the reader the impression that there is a difference, and it does that loud and clear. Added ref for those non-engineers about the significance of the volume of the cubes. 199.125.109.129 03:49, 31 October 2007 (UTC)

I'm taking this graphic down based upon the consensus viewpoint expressed above. Mrshaba 19:33, 31 October 2007 (UTC)

There is no consensus for removing it. I still like it, and I'm putting it back. 199.125.109.41 21:30, 31 October 2007 (UTC)

Everyone else has disagreed, with a reason. Graphical illustrations are good, yes, but that doesn't mean that ANY graphical illustration is good. The cubes are not a good illustration. Understanding it requires conceptualisation. Energy doesn't come in cubes. The point it tries to make is not a difficult point to understand. The graphic does not deserve to be in the article. --SmokeyJoe 01:31, 1 November 2007 (UTC)

Most people are visual. So having the ratio expressed in an image is much more valuable than expressing it as a number. I added a footnote to explain what the cubes represented. 199.125.109.136 03:26, 1 November 2007 (UTC)

I don't think that helps much. The coneptualisation required is still too much for someone who doesn't already understand. If you already understand, it is too boring. Maybe if it was a flea on a mouse on an elephant, it might help with recognition. --SmokeyJoe 03:42, 1 November 2007 (UTC)

While that might be the right ratio it would be a weird diversion and it would be very hard to relate back to energy. 199.125.109.136 04:00, 1 November 2007 (UTC)

Cubes are a diversion unrelated to energy. --SmokeyJoe 04:03, 1 November 2007 (UTC)

You know it's funny that you even mention cubes - all I see is an 800 pound gorilla on one side and a pebble on the other. 199.125.109.56 05:09, 1 November 2007 (UTC)

Is that a joke? Is there a subtle point? Can you find anyone, even a non-wikipedian, who agrees with you that the image is should be used? --SmokeyJoe 05:41, 2 November 2007 (UTC)

In order to find out, I printed out the article and the diagram and asked random people if they thought the image was a good illustration for the article. Almost everyone said it was good to excellent. The only people who didn't like it were also people who thought we should develop nuclear power. The question they were asked was, "In order to meet our energy needs for the next 50 years should we develop nuclear power or solar power." No one chose only nuclear, and only a few chose both. Almost everyone chose only solar. 199.125.109.56 03:56, 3 November 2007 (UTC)

The people who responded to the Rfc have responded negatively to the cube diagram. The count seems to be 4 out of 5. Cheng Houston, SmokeyJoe, NameThatWorks and myself all have a poor opinion of the image. 80% is a strong and clear consensus. I am going to remove this picture. Mrshaba 05:48, 3 November 2007 (UTC)

First of all, your question was unrelated to the matter at hand. Anybody would chose solar, simply because the cube is bigger. However, the image is deceiving, because it is three-dimensional. Not only that, but it as a boring graphic that could be easily explained in a sentence or two in the actual article. -Rycr (talk) 08:12, 18 November 2007 (UTC)

Consensus means either that everyone likes it or no one likes it. Since there is no consensus to remove it, it stays until something better comes along. 199.125.109.56 06:02, 3 November 2007 (UTC)

This is from the intro of the How to Lie with Statistics page. I think it's relevant here.

By representing one-dimensional quantities on a pictogram by two- or three-dimensional objects to compare their sizes, one makes the reader forget that the images don't scale the same way the quantities do. Two rows of small images would give a better idea than one small and one big one. Mrshaba 03:36, 8 November 2007 (UTC)

What that refers to is that one row would be say 89 m long and the other only 1.5 cm long to accurately show the difference between solar and consumption. Obviously the page isn't large enough. Log scales are also used to compare large ratios, using a semilog chart. The log of 89,000 is 4.95, 370 is 2.57 and 15 becomes 1.18. The problem with logs is there is no way to visualize the actual quantities. When we hear of an earthquake being 6.8 and another being 6.5 they sound about the same, but one is twice as powerful. Log graphs are best used in data analysis where you are looking for trends, to see if the trend is linear or exponential. So if you made a semilog graph of solar wind and consumption the average reader would probably look at it and say, hmm they are all about the same, wind is about twice consumption, and solar is about twice what wind is, both being totally false conclusions. So far the cubes seem to be the best proposal. Visually it lies by making it look like solar is, what 18 or 20 times bigger than consumption, instead of 5,900 times bigger, but that doesn't matter, it still conveys the concept that solar is a lot bigger. 199.125.109.27 03:59, 10 November 2007 (UTC)

The graphic appears to be representing false information anyway. Evidently it represents the total incident solar energy, which of course is not all available for use. In fact it would seem that only the amount of energy which is reflected or radiated back into space is truly exploitable - the rest is used in warming, powering currents, supporting life and so on.Wphamilton (talk) 22:11, 19 November 2007 (UTC)

The energy reaching the surface and not reflected back into space is available, but with present technology photovoltaics, about 15% can be captured and turned into electricity. It is unlikely that all of the earth will be covered with photovoltaics, however. We can get all the energy we need by only covering a tiny fraction of a percent, which is clearly shown by the graphic. The 85% that doesn't get converted into electricity from a solar panel still goes on to warm the earth, power currents, support life and so on. Photovoltaics can be made dark colored so they reflect less energy back into space, or with reflective areas so that they reflect more energy back into space. 199.125.109.56 (talk) 16:11, 20 November 2007 (UTC)

Pardon my lack of clarity, that's not what I meant. Any of the incident energy not reflected or radiated is already "spoken for" by the earth and ecosystem and therefore "not available for use" even though you could technically capture it. The graphic implies that a vastly greater amount of energy is theoretically available when the reality is much less. So the graphic is inappropriate in my humble opinion. 24.126.145.215 (talk) 20:09, 20 November 2007 (UTC)

The reality is that is the amount of energy available. What we need is less than a tenth of a percent of what is available for all of our energy needs, so there is no cause for concern of us using all of it. Of course if it was all used, it would have to be re-used to power lamps to grow trees, fans to create wind, and heaters to warm the earth. Conservation of energy says that you can not create or destroy energy, you can only convert it from one form to another. We often do use lamps when sunlight would work much better. The graphic is quite accurate. 199.125.109.129 (talk) 18:08, 23 November 2007 (UTC)

I think that the point is indisputable, that not all incident energy is "available for use." Only a tiny fraction is, in fact available for use. If the caption read "total incident energy" instead of "total available energy" it would be correct. As it is, it is simply advocating development of solar energy using a misleading statistic. I don't want to jump into any wiki-politics, but in my opinion the article would be better with the graphic simply removed and I don't understand why the graphic remains against almost such strong opposition.Wphamilton 20:20, 30 November 2007 (UTC)

What is indisputable is only that we only need or will use a tiny fraction of what is available. It's like if you have a river flowing by your land, how much of it is available for you to use to water your lawn? 199.125.109.43 22:49, 30 November 2007 (UTC)

So the point of the graphic is advocacy rather than accuracy. Is that allowed in wikipedia articles?Wphamilton 19:12, 1 December 2007 (UTC)

The point is availability, not advocacy. Economic factors determine utilization. 199.125.109.56 20:36, 1 December 2007 (UTC)

Nope. If you were to block off half the sunlight hitting the Earth, what would happen? Obviously, you'd never do that. Just as obviously, that energy is not "available" for use. It has nothing to do with economic factors. The graphic is wrong and violates the neutrality requirement, because it is designed for advocacy Wphamilton 08:51, 2 December 2007 (UTC)

You are certainly entitled to your opinion, my opinion is that the graphic was designed solely in the interest of accuracy. If it was designed for advocacy it would be advocating that we increase our energy consumption by a factor of 50 to 100 times, and that obviously was not the intention of the graphic. 199.125.109.43 04:35, 3 December 2007 (UTC)

Image:Sunspot TRACE.jpeg

Exciting solar surface illustration, but relevence is unclear. --SmokeyJoe 21:42, 22 October 2007 (UTC)

This is my favorite of the sun pictures. The caption was adapted from the heat article and I'd like to keep something like this caption. The caption on the ISS image can also be moved into this picture. Mrshaba 23:09, 22 October 2007 (UTC)

Definitely not relevant to article. 199.125.109.124 02:17, 23 October 2007 (UTC)

Image:ISS on 20 August 2001.jpg

Nice illustration of solar energy collection by a satelite. Not a very good connection between image and caption though. --SmokeyJoe 21:42, 22 October 2007 (UTC)

I prefer this technology picture because it is crisp and also international which is good. The caption could be changed to something like: The use of solar panels on the International Space Station highlights the advantages which solar power has in remote applications. Most solar energy applications are more down to Earth. Mrshaba 23:09, 22 October 2007 (UTC)

The picture is great, but spacecraft and the ISS are not what comes to mind via the term "remote applications" (need a photo of a project in the desert or jungle for that). The caption for this photo should mention the importance of PV to the space program and the efficiency of PV arrays above the atmosphere. --NameThatWorks 15:42, 29 October 2007 (UTC)

Definitely not relevant to lead. Put it in the solar in space article. 199.125.109.124 02:17, 23 October 2007 (UTC)

Lack of a picture of the sun!

Now that the sunspot and solar flare images are gone, there is no picture of the sun. I think an image/figure showing the sun belongs at the start of the article.

I tried Image:The sun1.jpg (shown right?), but someone pretty quickly didn’t like it. Images of the sun showing stuff in the foreground are pretty difficult to photograph, but I think some figure showing the sun, but not as a closeup, is needed. --SmokeyJoe 05:41, 2 November 2007 (UTC)

Image:Sun920607.jpg

Fairly boring sun image except for its illustration of sunspots. Are sunspots relevent here? --SmokeyJoe 21:42, 22 October 2007 (UTC)

This is the image that long held the lead on this page but I found it rather sleepy so I changed it out. Vantucky pointed out this image is already used in the lead on the Sun page which makes its use here inappropriate. Mrshaba 23:09, 22 October 2007 (UTC)

Image:171879main LimbFlareJan12 lg.jpg

Exciting solar surface illustration, but relevence is unclear. Caption doesn't explain figure. --SmokeyJoe 21:42, 22 October 2007 (UTC)

I also like this image although not as much as the sunspot TRACE image. This image is used as the lead on the heat page with the caption "Heat from the sun is the driving force of life." Mrshaba 23:09, 22 October 2007 (UTC)

Definitely not relevant to article. 199.125.109.124 02:17, 23 October 2007 (UTC)

Image:171879main LimbFlareJan12 lg.jpg

Actually, this might be a good candidate. Because we are talking about solar energy, which is captured and used on Earth (or around it, if you take satellites into account), it is good to show a view of it from the Earth itself. Plus, the caption fits the article perfectly. -Rycr (talk) 07:59, 18 November 2007 (UTC)
I agree with Rycr on this one. This is probably the best one of these pictures to put on the page.

Image:Sun in X-Ray.png lg.png

This is a very popular picture on the international WP sun pages. Mrshaba 00:28, 7 November 2007 (UTC)

ImageImage:Sun in Celestia without words.PNG| lg.PNG

Is this really an image that can be used on Wikipedia? It says it's a screenshot but doesn't say where it is from. Isn't this an obvious copyright violation? 199.125.109.27 21:47, 10 November 2007 (UTC)

Image:Sun minus Venus.PNG| lg.jpg

If you are going to use this photo, use the original not one that has been modified. 199.125.109.27 23:05, 10 November 2007 (UTC)

Whatever happened to Image:SolarStirlingEngine.jpg? The article now begins with three awful pictures/figures. --SmokeyJoe 08:11, 15 November 2007 (UTC)

Rfc regarding pictures

The choice of pictures has been a distraction to the forward movement of the page. I initiated the Rfc to gather information which could be used to consensually choose the pictures in the lead and control this distraction but somehow the issue of picture choice in the lead has expanded to the picture choice on the entire page. Sizing of pictures in particular has become an issue and all of the pictures on the page have been reverted to thumbs. In my opinion this is a step backwards which has subtracted from the quality of the page but I foresee polishing editors moving pictures around and resizing pictures for maximum effect so I'm not too worried.

In regards to the picture choice there is room for two pictures in the lead. It seems clear that one picture should be of the sun and one picture should be of a solar technology. I personally think the solar technology picture should be a PV technology because the majority of visitors to the page will be interested in PV.

Another consideration is that the pictures should be chosen in tandem to some degree because of color considerations. Technology pictures which incorporate strong green or blue colors would in general work well with the red or yellow colors of the final sun picture. The only other consideration is that the sun picture should express both heat and light. Solar energy technologies predominantly use both heat and light so choosing a sun picture that expressed both heat and light would help understanding. Mrshaba 17:31, 2 November 2007 (UTC)

To put it simply, the pictures in the lead should succinctly express the the main uses of solar energy. These uses are heat, light and electricity. A picture of the sun can be used to cover heat an light and a PV picture can be used to cover electricity. Mrshaba 17:53, 2 November 2007 (UTC)

What works for me is one photo that is representative of solar technology and one image that demonstrates the availability of solar energy, which is what we currently have. The photo should probably be rotated occasionally, because no one image can cover all of the different implementations of solar energy. 199.125.109.56 05:00, 3 November 2007 (UTC)

RE picture sizes. Mrshaba, What setting do you have for viewing thumbs? Why do you think the images should be bigger on this page than for other pages on wikipedia?

Also, why are all the pictures aligned right? --SmokeyJoe 23:49, 3 November 2007 (UTC)

It seems like the pictures are different sizes on the Sun page for example. The pictures are all on the right because working on the content of the page has been more important than moving pictures around. I also stopped experimenting with the pictures because Anon got in the way so I moved back to working through the material for the most part. 69.229.196.79 01:06, 4 November 2007 (UTC)

I see the pictures but there is nothing wrong with that pictures looks in this page. But seems it needs to revised the pictures for the demonstration or presentation of the solar energy source.--Ellainecondes 20:02, 5 November 2007 (UTC)

I looked through the Sun pictures on all the WP language sites. The Italian sun page tried to hypnotize me and I found out the sun is called Howl in Kernewek and Nap in Magyar. Here are some of the pictures I found notable: [1], [2], [3], This one could go in the storage section to explain the intermittent nature of solar energy [4], [5], there are a million sunset pictures but one like these could be used eloquently at the bottom of the page [6] or [7], simple [8], another way to show energy flow [9]. Mrshaba 00:17, 7 November 2007 (UTC)

I believe this might be an open source picture jackpot. [10] Mrshaba 04:10, 13 November 2007 (UTC)

I verified with the contact at Sandia that all the pictures in the search engine are indeed open source. The only expectation is that Sandia National Laboratories be acknoledged. Mrshaba 17:12, 13 November 2007 (UTC)

Mrshaba 00:57, 7 November 2007 (UTC)

what is the solar system

--70.129.25.143 18:46, 3 December 2007 (UTC)--70.129.25.143 18:46, 3 December 2007 (UTC)

It's a big structure with lots of planets, but that's not important right now. --NameThatWorks 17:32, 4 December 2007 (UTC)

Environmentalist opposition

The new addition to the page needs some attention, I feel. First, the newspaper story does not constitute evidence of any general critique of solar power coming from an environmentalist direction, only a criticism of one particular proposal in one location. It is not the same situation as with wind power or tidal power where these sorts of objections are commonplace in public debate. Second, if it is to appear in the article it has to be in the right place. Third, we must make sure that it is not too long so as not to give undue weight to this minor point. What do others think? Itsmejudith (talk) 22:18, 5 December 2007 (UTC)

It looks to be an objection to power lines if anything. I don't think it belongs at all. Mrshaba (talk) 23:43, 5 December 2007 (UTC)

Agreed. 199.125.109.134 (talk) 02:53, 6 December 2007 (UTC)

That device with the Stirling engines hanging high in the air and waving around in the sun looks like it must be a noise problem for miles around. Is it? 70.15.116.59 (talk) 17:17, 11 December 2007 (UTC)

Restore images

The new images, replacing Image:Breakdown of the incoming solar energy.jpg and the one below it need to be restored with the previous ones, they are not very good. Also restore the two images removed from the lead. 199.125.109.41 (talk) 12:50, 7 December 2007 (UTC)

PV price/production graph

I wrote and talked to Paul Maycock several weeks ago and he gave me data from which I've developed a PV price vs. production history graph. The original data was cumulative MW installed and real $/kW. There is one online reference from Maycock which closely mirrors the numbers I used but Paul sent me updated and more complete data so I relied on this info to fill in the table which the graph is based upon. From Maycocks original numbers I derived production per year figures and used an inflation calculator to translate the real $/kW info into inflation adjusted $/kW. The table and graph are not yet complete in my mind. Maycock informed me that commercial PV production did not begin until 1972. Prior to this pseudo-commercial production consisted of toys and gadgets which relied on off spec PV cells from the space program. As it stands I still need to acquire data for 1972-1974 to completes the commercial portion of the table and graph.

Maycock's numbers are solid. I'll have to find out from Perlin what "kind" of numbers he used before the PV section can be written consistently. This has been a time consuming adventure. My question now is how should the data be presented? Should this page compare PV prices (real and inflation adjusted) or something else? I'm open to suggestions? The graph below shows both prices and production on separate right and left logarithmic axes. The two graphs that trend downward together are the price graphs. The upward ramping line is production. Mrshaba (talk) 16:47, 8 December 2007 (UTC)

Different lead photo?

The current lead photo has a distinctive appearance, but a rather technical legend - more to the point, there's a section below that introduces three types of concentrators (trough, power tower, and parabolic dish) but only has examples from two of them. It looks like the current lead photo was looted from that section.

As a lead photo I'd suggest Solar Two:

Simply because this is the most iconic "solar power plant" you see everywhere from movies to SimCity, and the first example of a large-scale solar power plant.

Alternatively you could use a picture of a solar cell, though this seems somehow more specialized (even though in a way it is less so). 70.15.116.59 (talk) 17:27, 11 December 2007 (UTC)

Challenge that solar is 99.9% of available renewable energy.

The statement in the introduction that solar energy is 99.9% of available renewable energy needs to be justified. The citations go off line and cannot easliy be checked. The Geothermal_power#Potential section seems to suggest that a large potential exists for geothermal energy with a recent MIT report calculating the world's total Enhanced Geothermal Systems resources to be over 13,000 ZJ. Geothermal power is derived from the Earth's rocks and not from the Sun. This article seems to me to exagerate here. Lumos3 (talk) 23:08, 25 December 2007 (UTC)

It is sufficient to use "most" instead of being grandiose and making up a number that is not easily checked. In the body of the article it is ok to be more specific. Normally it is not a good idea to have any references, or any need for any references in the lead paragraphs. 199.125.109.56 (talk) 15:15, 28 December 2007 (UTC)

References

What's up with the non-standard reference style of putting "See:" everywhere? I wouldn't have clicked on the reference if I didn't want to see it, I don't need to be told to see it. It is not normal to combine references, it is more common to list them separately, and where the same information is available from multiple sources just use the best source. There also appears to be too great a reliance on book sources instead of sources that can be verified through the internet. 199.125.109.56 (talk) 16:03, 28 December 2007 (UTC)

Poor citation

"Conventional HVAC systems account for roughly 40 percent of the energy used in the United States and European Union."

The cited article in fact states

"Residential and commercial buildings already account for roughly 40 percent of total primary energy use in the United States and the European Union. With HVAC&R and water heating responsible for a significant percentage (75 percent of residential and 64 percent of commercial building site energy use)"

So the figure is in fact closer to 28%. It's hard to put an exact number on it given that we don't know how that 40% is split between commercial and residential.

85.210.14.62 (talk) 23:34, 2 January 2008 (UTC)

Vandalism

Why is this page not semi-protected?

Why do we have to waste time checking and reverting this and other pages damaged by rescidivist or random inputs?

Why arent all pages automatically protected from vandalism and other viral, corrupt or malevolent inputs?

I dont know why wikipedia continue a policy of allowing unregistered no account editing, although at a guess it would seem to be ideological or a failure to let go of a previous belief despite the facts of ongoing and increasing vandalism, therefore vandalism can be seen as an imposition upon users by wikipedia administration for its own reasons.

Isnt this the sort of decision that registered users should vote on?

What do you think?

--Theo Pardilla 11:40, 31 January 2008 (UTC)

Most of the edits to Wikipedia are by unregistered IP users, many of whom only make one edit. It is not Wikipedia policy to prevent them from editing any article. Page protection is done temporarily to keep the vandalism in check, but when pages are protected you also lose contributions from millions of users. This page gets protected from time to time, but should not be permanently protected. No page should be permanently protected, or let me correct that, no article should be permanently protected. Some of the internal pages like commonly used templates have no reason not to be permanently protected. The only way to find out if a page needs to be protected is to remove protection and see what happens. 199.125.109.57 (talk) 17:12, 31 January 2008 (UTC)

In the news

Wiki-article for sale... Only $497. http://energybusinessreports.com/shop/item.asp?itemid=1457&affillink=EPRW20080124 66.122.72.201 (talk) 19:33, 11 February 2008 (UTC)

Solar energy sea platforms

A very promising idea I heard recently is sea platforms filled with solar panels. Here's a source on it http://www.solarenergyltd.net/energy island.htm --fs 10:49, 12 February 2008 (UTC)

Sounds interesting - 70% of the surface of the earth is water. However it seems more likely that we will get all the energy we need from land based solar installations like on rooftops and from carports covering the vast parking lots we now have, not to mention from all the available desert lands. I don't imagine the oceans will ever be crowded with energy platforms. I think the estimate is that we need 0.02% of available solar energy? So the 30% available from land will be quite sufficient. 199.125.109.62 (talk) 18:15, 13 February 2008 (UTC)

Energy from the Sun

Solar energy#Energy from the Sun had figures that contradicted the figures in Image:Breakdown of the incoming solar energy.jpg and figures derived from simple albedo considerations.

Image has 174 petawatts incoming solar, ie 5490 zettajoules per year;
Image has 122 petawatts absorbed (89 by land and sea plus 33 by atmosphere), ie 3850 ZJ per year;
3850 is almost exactly 70% of 5490 so that implies 0.3 was used for Earth's albedo, so far so good;
The image does not give the energy absorbed by the sea alone, and although the ocean's albedo is complex it seems to remain below 0.3 (0.03 to 0.3 from http://snowdog.larc.nasa.gov/jin/getocnlut.html)
Therefore the energy absorbed by the sea alone should be *at least* 71% of 3850 ZJ, ie. 2733 ZJ
But the article's section states a too low 285, maybe a lost zero?

I do not have access to the cite "Smil 2003", so I cannot be sure it was referring to energy absorbed, although that seems likely. Therefore I have added a zero to the 285 and added a Fact tag because to me 2850 is just as much a guess as my 2733. -Wikianon (talk) 15:35, 19 February 2008 (UTC)

- Verifying the energy absorbed by the oceans has been a long term todo. The number was derived from another wiki-article but the information was unsourced. The Smil ref does not refer to the energy absorbed by the oceans but instead gives the total energy flow. Good eyes. The number definately needs to be fixed. 131.89.192.111 (talk) 17:47, 19 February 2008 (UTC)

It looks like what they were trying to get at is how much energy is available from the sea. If you look at the diagram, 89 PW comes in and 88 PW goes back out, which due to rounding error, is the same number. 199.125.109.41 (talk) 17:55, 19 February 2008 (UTC)

Thermal mass storage

This part is written in an odd and perhaps misleading way. It's discussing energy storage, not electricity storage, but it talks about reducing the need for COOLING during peak hours, how does that work? I know you can produce ice at night and cool during the day using that, but that's totally unrelated to solar energy. Also at the end it says that one system has 99% efficiency, but this is for HEAT storage, not electricity storage. If that were for electricity storage then companies would already be using it to offset peak demand, since hydro storage only gets about 25% efficiency. Basic thermodynamics dictates that you can't get more than 70% efficient (see carnot heat engine), but that's a wild over-estimate when one considers doubled transmission losses, losses of heat entailed by boiling the water (phase change losses), the fact that the ambient temperature is NOT absolute zero. So I've changed the wording to make it clearer that's it talking about heat loss and it has nothing to do with electricity generation. Hvatum (talk) 17:09, 9 April 2008 (UTC)

I agree that the particular bullet point you edited is a bit confusing in the context of the surrounding text. But first things first: I don't see where this section of the article says anything about thermal storage reducing the need for cooling during peak hours. It does mention reducing peak demand, and it does mention reducing overall heating and cooling requirements, but those two statements don't imply reduction of cooling requirements during peak hours.

As for the particular bullet point you're commenting on, it isn't entirely clear to me where your confusion comes from (I see several potential sources). What the section is trying to say, though, is that molten salts can be heated by the sun to temperatures comparable with those found in a power plant run on conventional fuels. Once they are heated to that level they can be used to run a turbine and generate electricity (click on the Solar Two link in the article). That is the reason for the power station discussion in the section. You appear to have interpreted it as some sort of electric power storage system like a battery, where electricity goes in when not needed and goes out when needed. In this case, "storage" refers only to keeping the heat from the sun's rays until needed, so the Carnot efficiency does not apply (obviously it does apply to getting the heat in to the molten salt in the first place, but that's a different topic).

Since you appear to have made your edit under the impression that the article was talking about an electrical battery of some sort I am undoing it. I do agree that the section could use a little clarification and tidying up, though.--Squirmymcphee (talk) 20:10, 9 April 2008 (UTC)

As pointed out by Squirmy above, the point I was trying to make is that solar energy can be store efficiently as high grade heat. The storage efficiency is determined by comparing the heat in vs heat out but does not consider the capture efficiency or conversion efficiencies on either side of the storage stage. When considering pumped hydro by the same criteria you come to an efficiency (electricity in vs electricity out) of 80-90%.

I'll try to tidy up the page where it seems things have deteriorated. Mrshaba (talk) 22:42, 9 April 2008 (UTC)

Pumped hydrostorage is about 78% efficient. Hydrostorage, releasing water from a dam when you need it, is more than 99% efficient, but that's a different type of storage - it is the water you are storing, not the electricity, although the effect is the same. Hydrostorage - big dam projects like the Hoover Dam and the Three Gorges Dam - have mostly been tapped out, and are a wretched waste of natural resources in the name of progress. What you will see is development of a lot of pumped hydrostorage projects - which only require a hill and a small supply of water to replace what is lost to evaporation from the two reservoirs - to compensate for the intermittency of solar power and wind power as we switch from coal to wind and solar as our primary source of electricity. 199.125.109.41 (talk) 14:00, 24 April 2008 (UTC)

Economics etc.

Seems to me that the section does not have enough on the economics of solar thermal and assumes that the only interesting issues are in relation to PV. Does anyone have something to hand that can be added? There will be material on subsidies for solar hot water in the UK but it would be much better to give examples from countries where this is more developed. Australia? Itsmejudith (talk) 22:42, 24 April 2008 (UTC)

I agree with this blurb from the Nuclear Power article:

Economics

   Main article: Economics of new nuclear power plants

This is a controversial subject, since multi-billion dollar investments ride on the choice of an energy source.

Which power source (generally coal, natural gas, nuclear or wind) is most cost-effective depends on the assumptions used in a particular study—several are quoted in the main article.

I think we should blend economic info into the individual sections when we can but leave the heavy lifting to solar economic articles which are to follow. Mrshaba (talk) 16:36, 25 April 2008 (UTC)

EROI

This article is full of facts and figures -- but manages to avoid the most important measures. What is the embodied energy of the various forms of solar, and what is the EROI? How long do typical systems take to pay back the energy used to make and install? How much more energy is produced over typical system lifetime? -69.87.199.222 (talk) 13:21, 11 April 2008 (UTC)

Modern PV and solar water heaters pay back the energy it takes to build them 10 times over their lifetimes. Squirmy could give you a more detailed response I'm sure but to my understanding this is no longer a technological issue. The CdTe thin film products in particular have a very short EROI. To my thinking the most important measure is the price of the energy produced. Mrshaba (talk) 19:47, 11 April 2008 (UTC)

EROI, "Economic Return On Investment" is actually more important than energy return on investment, which is more of an academic exercise - are we actually getting any energy out of this, which is a yes or no question, not a metric. The answer is yes. Economic return on investment strongly influences the rate of investment in the technology. It's now below the warranty period, which is why investors have been willing to install solar panels for free for a year now, in return for a guarantee of payment for the electricity generated. All the renewables have been almost exponentially dropping in price. 199.125.109.57 (talk) 18:23, 12 April 2008 (UTC)

Photovoltaic EROI has certainly improved since this report due to efficiency gains, silicon usage improvements and the significant expansion of manufacturing capacity but it's a starting point.

www.nrel.gov/docs/fy04osti/35489.pdf

This solar water heater studied in this paper returned its energy investment in 191 days and had a 20 years expected life time.

www.itee.uq.edu.au/~aupec/aupec06/htdocs/content/pdf/83.pdf

This combined solar space and water heating system had an 18 month energy payback period.

www.wseas.us/e-library/conferences/2006elounda2/papers/538-244.pdf

Considering how EROI arguments have been used against PV in the past it's probably a good idea to include some of this information. Mrshaba (talk) 18:45, 29 April 2008 (UTC)

Solar thermal help

Thorough review of potential solar thermal technologies. [11] Mrshaba (talk) 23:53, 30 April 2008 (UTC)

Solar still help

Good reference to improve the solar still section. [12] Mrshaba (talk) 22:43, 30 April 2008 (UTC)

Technical details of solar distillation. [www.psa.es/webeng/aquasol/files/Congresos/JBlanco - EuroSUN2002.pdf] Mrshaba (talk) 16:42, 3 May 2008 (UTC)

Page layout, captions and pictures

This has certainly been an ongoing process. One major difficulty I've had is determining what browser size to "design" for. I found some helpful guidance here [13] and here [14]. Good luck finding a browser resizing utility but they're out there. I am now using a 1024x768 window to help make decisions about picture placement and answer questions like how big or how many pictures there should be.

In my opinion the CSP section has too many pictures judging from the run on in 1024x768 screens and higher. More importantly the captions have been sacrificed. It's worth mentioning that, "Along with the title, the lead, and section headings, captions are the most commonly read words in an article, so they should be succinct and informative." The article previously had overly brief captions. The more informative captions throughout the article were written with the help of a technical writer and were a welcome improvement.

There are many considerations that go into choosing pictures. Many of these are a matter of taste and since there is no accounting for taste what considerations do count? Quality and appropriateness of course but what else? The article has purposely been written to include solar technologies in as many places as possible. When choosing to describe a solar technology in country X against one in country Y the article as a whole is considered. The US with its technological achievements has had no problem being represented on the page. For me, if there's a choice between material from the US vs. Mexico I'm prone to use the info from Mexico just to keep things interesting. The pictures I've chosen follow this reasoning where possible so when it comes to a choice between the Solar Two in the US and PS10 in Spain I'm prone to choose PS10 simply because there are no other pictures from Spain on the page. Factoring in the fact that PS10 is brand new and Solar Two is decommissioned seals the deal for me.... But that's just me. Mrshaba (talk) 16:44, 2 May 2008 (UTC)

Not quite just you. I also like to see a lot of variety in the illustrations.Itsmejudith (talk) 18:40, 2 May 2008 (UTC)

Pictures should normally be unsized - use thumb and let the user preferences choose the size. The only exceptions are exceptionally odd aspect ratio photos that need to have a size added to make them meaningful. Artistic layout of an article can be done by someone who has that gift - it has nothing to do with the content of the article. Since a wiki is a collaborative effort I would suggest sticking to the skills that one has in abundance and leaving others to contribute according to their specialties. I would still recommend against editing only one article. A lot can be learned by clicking random article and editing whatever comes up. 199.125.109.31 (talk) 19:12, 4 May 2008 (UTC)

We all have different ways of editing. I like editing a very wide variety of articles, but rather than editing random articles, it is perhaps more helpful to assist with urgent tasks. I would recommend the wikification wikiproject to anyone who wants to be as helpful as possible. Itsmejudith (talk) 16:29, 5 May 2008 (UTC)

Can we clean up?

The To Do list is a bit dated and I'd like to clean it up.

Reformat references to Harvard style. Improve quality of references where possible.
References needed at a couple of points in the PV section.
Improve Concentrating Solar section.
Find or develop a clean graph of solar price history and MW production from 1972-present. (Commercial manufacture began in 1972.) I still need backup data for 1972,1973,1974.
Use more examples of cars and planes in the solar vehicle section. Add trains and bikes.
Get a better picture of the solar still and solar cooker.
Fill out use of concentrating solar in process heat section. Use 1 or 2 more examples.
Add solar kitchen to Solar cooking section.
Add more to Fixed reflector/Dual axis receiver example. Cost/Efficiency/Temperature possibly.
Add thermal mass properties of water and list a few applications of water in the Energy storage section. Remember that both hot and cold water are used to offset energy use.
The solar still blurb needs to be reworked.
Reduce size of article.
Economic information is key to uptake and is not addressed properly by green flavoured advocacy of article.

My take on the to dos.

(1) The references can still be improved but I don't think this is of the high priority it once was.

(2) Can be removed after citation tags are placed directly the specific info that needs references.

(3) This to do should be made more specific or removed.

(4) This can be done but maybe this graph is better suited to the photovoltaic page.

(5) A few more solar powered vehicle examples can still be used here.

(6) A quality picture is still needed here.

(7) The new Frito Lay facility in Modesto would be an excellent addition here.

(8) The solar kitchen in India and mention of Scheffler concentrators remain to be added.

(9) Probably overkill. Also there are not enough fixed reflector examples to give a good idea of costs.

(10) A short list of the properties of water can still be added.

(11) Some improvement is still needed on the solar still. If someone knows of a good reference that would help.

(12) The size seems fine.

(13) I assume this to do is directed at PV economics but I'm not sure. Including economic information on all of the various solar technologies would be nice but I think it's generally beyond the scope of this article. —Preceding unsigned comment added by Mrshaba (talk • contribs) 01:09, 10 April 2008 (UTC)

The size (68,406 bytes) is horrendously large and should be reduced to 30,000 to 40,000 bytes maximum. I see that my arch nemesis has returned from their wikibreak, and picked up the same editwarring from before leaving (Did you restore the article from history or from a local file on your hard drive?). It's as though the hard work of three months editing has just gone poof. 199.125.109.41 (talk) 23:09, 10 April 2008 (UTC)

The readable size of the article is currently a dab under 40 kB. This size is within your specifications and reasonable according to the Article size guidelines. [15]. Mrshaba (talk) 05:37, 30 April 2008 (UTC)

I agree that the article is not "horrendously large". Perhaps we can trim the odd sentence here and there. Thank you very much for your comments on the to-do list. Itsmejudith (talk) 07:50, 30 April 2008 (UTC)

Readable size is less important than edit byte count. There are even sections of the article that are over 32 kb and show an edit count because of that. Since the article covers everything and the kitchen sink it is not possible to cover each topic without going way over budget, without making use of subarticles. Cutting a few sentences here and there will not allow the 50% reduction that is needed. 199.125.109.57 (talk) 02:04, 6 May 2008 (UTC)

<=My word!!! Prodigiously preposterous I say. However ever did these drivelings squirm their way to GA status? This muckity muck worm of a page needs a shavin'... it's clearly all tailin's.

We need somebody special to come in and help us with this. He’s gotta be strong and he’s gotta be fast...Something like a streetwise Hercules. Something sorta like a Solar Superhero of some sort. Hmmm. Mrshaba (talk) 03:04, 6 May 2008 (UTC)

You know perfectly well how this article got to GA status - by a high school kid whose very next GA review was instantly reverted, at a time that the article was as yesterday being constantly revised by one editor, which was the reason it was quick-failed the previous time it was proposed for GA status - for not being stable. 199.125.109.57 (talk) 16:23, 6 May 2008 (UTC)

Optimization of sunlight in agriculture/forestry

Food for thought.

http://www.ars.usda.gov/research/publications/publications.htm?seq_no_115=207988

http://www.jstor.org/pss/988906

Mrshaba (talk) 16:23, 5 May 2008 (UTC)

Perhaps a quick mention of heliotropism. Mrshaba (talk) 17:11, 5 May 2008 (UTC)

Another source that may be useful in this section: "Purification and production of inorganic fertilizers in solar ponds" (J. Doria, M. C. de Andrés and C. Armenta) Mrshaba (talk) 16:49, 7 May 2008 (UTC)

There seems to be a problem with this info

I previously removed the following info but it has returned. On pg. 3 of the reference provided the term "solar" is described as representing .04% of the TPES. I see three problems with this info as it is presented in the article. #1. The "solar" term which makes up the TPES number seems to be assumed to be all PV but I don't think this is true. There's probably some CSP mixed in but I can't tell from the way the info is presented in the reference. #2. The source talks about solar hot water but the energy produced by these systems is clearly not accounted for in the statistics. #3. The 48% growth seems to be for wind rather than solar. So I'm challenging the validity of this info. I recommend finding a source that breaks down the quantity of energy PV produces world wide and using that.

"Photovoltaics provided 0.04% of the world's Total Primary Energy Supply (TPES) for the year 2004, increasing by an average of 48 percent each year since 2002, at a rate of growth to reach 0.40% by 2010.[5]" Mrshaba (talk) 03:26, 6 May 2008 (UTC)

Wind is only growing at 28% per year. Not sure why you thought the 48% number was for wind. Additional ref added. 199.125.109.57 (talk) 16:11, 6 May 2008 (UTC)

I opened the source and used CTRL F 48. Wind's growth rate pops up as 48.1% with solar as 28.1%. The second source mentions the higher growth rate of solar over the last 5 years. The numbers are 25-30% higher than the info Maycock provided me but it's a source. There still seems to be a problem with points #1 and #2 above. There's also an issue with using the growth rate from reference two to extrapolate the numbers from reference one.Mrshaba (talk) 16:56, 6 May 2008 (UTC)

The numbers from the second source are misleading. They seem to include idle production capacity to make production look about 33% higher than it is. [16]Mrshaba (talk) 17:27, 6 May 2008 (UTC)

Page 50 of this source lists PV energy production as 1 TWh (3.6 petajoules) in 2001 when PV installations were around 1 GW worldwide. Page 50 also lists the other solar technologies and if you add them up (206 PJ) and divide this number by worldwide energy use (approximately 471,000 PJ - 2004 number) you come up with the .04% figure from the IEA ref. The math works but the .04% figure quoted in the IEA source is counting all solar inputs. The .04% number should not be used to describe PV's contribution.[17] Mrshaba (talk) 18:34, 6 May 2008 (UTC)

Are you OK with just going ahead to make the edits based on the sources? Itsmejudith (talk) 19:09, 6 May 2008 (UTC)

<=You know me Judith... Mrshaba (talk) 19:24, 6 May 2008 (UTC)

Uh, it would be better to replace the number with whatever you wish instead of just deleting it. As far as I can see 0.039% of TPES by solar is a reliable source. You may be right that it is all solar, so just change it to solar instead of pv if that is the case. It would be better if you clarified what source you were talking about. I see where you got the 28/48% numbers from but they go all the way back to 1971, which is 33 years, and if we step backwards we get that in 1971 about 8.5 MWp of solar existed in the world, but only 100 kW of wind. They do say "due to a very low base in 1971". Once again my math could be off. 199.125.109.57 (talk) 02:51, 7 May 2008 (UTC)

The source I used is [18]. TPES numbers do not belong in the intro. The deployment of solar in micro-units makes this technology difficult and expensive to count. Supply side energy statistics exclude demand side solar technologies such as passive solar architecture, low-e windows, daylight savings time etc. Mrshaba (talk) 15:59, 7 May 2008 (UTC)

TPES numbers (11,059 MToe) are not appropriate, but percentages and rate of growth are appropriate. Hopefully we can find some numbers from more recent years and a rate of growth that is consistent with the percentage - there is no point in giving percent of TPES, or percent of electricity generated for all of solar and rate of growth for only one segment of solar - creating an apples and oranges comparison situation. 199.125.109.57 (talk) 16:08, 7 May 2008 (UTC)

Your ref (part IV) is from 2001 and not very useful - I would rather see data for growth from 2004 on rather than growth from 2001 to 2004. 199.125.109.57 (talk) 16:11, 7 May 2008 (UTC)

For example, wind power passed a huge milestone last year I think it was with more than 1% of global electricity being generated from wind power. Solar is about 2-3 years away from accomplishing the same mile marker, I believe. But that's just a guess. 199.125.109.57 (talk) 16:15, 7 May 2008 (UTC)

Peer review by Ruhrfisch

Ruhrfisch appears to be an experienced wikipedian.

The lead is supposed to be a summary of the whole article. My rule of thumb is that every header in the article should be in the lead in some way, even if it is just a word or phrase. See WP:LEAD

The semi-automated peer review has some good suggestions - several of them could be solved by using {{convert}} - I just checked and see it is used in some places, so perhaps it does not work for energy?

Will need to add kWh/MWh/GWh conversions back in.

A model article is often useful for ideas, examples - Renewable energy in Scotland is an FA and may be a useful model.

Provide context for the reader - perhaps add here When it meets the atmosphere, 6% of the insolation is reflected and 16% is absorbed. that the other 78% is transmitted (at least initially). See WP:PCR

Encyclopedic tone would avoid first person (such as All the food we eat, wood we build with, and fossil fuels we use are products of photosynthesis.[10]) and second person (If you want to light a 100 Watt bulb continuously you will need a battery and 500 Watts of solar panels.) This last one could be something like To light a 100 Watt bulb continuously, a battery and 500 Watts of solar panels are needed.

Done.

While the article is fairly well cited, there are some places that need references. For example, the 100 Watt bulb example above, or By contrast, typical solar water heating systems operating at 60% efficiency will deliver 4.85 to 14.5 MJ/m²/day. or the last four sentences on greenhouses. Every statistic needs a reference.

Per WP:MOS#Images do not set pixel widths beyond "thumb" for images so as to allow reader preferences to take over. Some wide images like Image:CSP schematics2.PNG are OK to set a size for. Vertical images can have "vertical" to make them smaller.

Done

There are several very short (one or two sentence) paragraphs that should be either combined with other paragraphs, or perhaps expanded. As it is, they interfere with the flow of the article.

Moved some of these paragraphs to the section below for now. Blended and mixed the remaining shorties.

There are several places that have bullet point lists - these are generally frowned on and should be made text if possible.

I removed two lists. There's still one in Energy from the Sun which seems appropriate but the list in Deployment, development and economics needs to be turned into text. I'm considering moving some of the development stuff out of the PV section and into this later section.

I think the images are generally good. Specific ones that seem excessive are as follows.

o I would choose one of either Image:SolarPowerPlantSerpa.jpg (at the scale shown the arrays in the background are unclear) or Image:Solar panels on house roof.jpg (I like the space station one and would keep it).

There's also colorful pink house with PV linked to below.

o I would also probably get rid of Image:CSP schematics2.PNG and just use the three actual photos that are near it in the article, perhaps making the captions slightly clearer that these are the three possibilities and perhaps moving one of these down into Experimental solar power (as these are all kind of experimental, right?)

Schematic is gone. Tried to clear up captions with better parallel terminology. Experimental is an admittedly poor name for the section. I wouldn't call grid tied SEGs plants or PS10 experimental. Novel maybe?

The article seems a bit long, but I am not an expert and am not sure what could be trimmed. Perhaps ask at a relevant WikiProject?

My take... Solar mechanical could probably be sacrificed although it does add a nice balance. Some of the PV section could be moved into the Deployment section which would save some redundancy. I shaved some from Water heating. Thermoelectrics could go although I've been running into this technology a lot lately. I moved some info to Solar chemical article which made that section shorter and removed the choppiness.

JMiall's comments

A quick scan through the intro (without properly reading the rest of the article):

'Solar energy is energy from the Sun in the form of heat and light.' - is this dumbing down too much? Surely all electromagnetic radiation from the sun should be mentioned and you could argue that the particles the sun spits out are an energy source. Even if 'heat and light' is used in the 1st sentence can we get more technically correct for the 3rd please.

I think light is colloquially understood to be roughly equivalent to visible light and heat is understood to be IR. I arrived at the definition after typing in define: "solar energy" to Google and after surveying the results I used a middle of the road definition. I find descriptions that use terms like electromagnetic spectrum or solar radiation miss the mark. I thought it was better than Solar energy is energy from the Sun. That being said, the intro is still in prototype mode. We can spice it up with smarter terms.

Here's another thing to consider. Incoming solar radiation (insolation) is a common term used to describe solar radiation. Unfortunately, this term is often confused with insulation and even insolation has separate descriptions. Sometimes it's described as radiation reaching the upper atmosphere and sometimes it's described as radiation reaching the Earth's surface. Mrshaba (talk) 00:48, 16 May 2008 (UTC)

This article is not actually about 'Solar Energy' as desribed by the first bit of intro, it is about 'The use of solar energy as an energy source on earth'.

Solar energy is both an energy resource and an energy technology. The article is definately about technology but Energy from the Sun is also the first section. The description of solar energy as a resource first and a technology second is common in the literature - Halacy, Daniels, most encyclopedic treatments, etc. I bet you if you opened up the very first edition of the journal Solar Energy you'd find something similar. I followed footsteps rather than a weedy trail. Solar technologies can be distinctly IR, visible or to a lesser degree UV technologies. Thermovoltaics use IR while photovoltaics are tuned to visible light. SODIS relies on UV while pasteurization is thermal. Another example is the solar chemical category which is divided between photochemical and thermochemical. Describing the two qualities leads into dividing the technologies. UV technologies don't quite fit in... Hmmm... I might be rambling.

'time of the early Greeks, Native Americans and Chinese' - the time of the early Greeks is very different from 1200AD mentioned in one of the refs. Did the Pueblo people do this deliberately though or was that just the way the cliffs faced? Also I'm pretty certain that people lived in S facing caves way back into prehistory! Did civilizations before the Greeks and Chinese not orient their buildings southwards then? Plus where does this information appear in the rest of the article?

The information does not appear in the rest of the article. The purpose of the information is to show that solar design has a long history and is geographically diverse. I constructed the sentence primarily for effect but I didn't make anything up. People all around the world figured out simple passive design ages ago. Socrates' Megaron house had several solar aspects that he described clearly. He's the quintessential Greek. Later when the Greeks started running out of wood because they cut all their forests down they turned to passive solar design. I'll try to throw supporting info into the body of the article. Recently, I was reading about the neolithic Banpo site in China and there is evidence they had a "solar orientation" of a sort circa 4000 BCE. That's wild if it's true. Much of the Feng Shui stuff is buried in astrological orientations which have nothing to do with good solar design but the roots of solar orientation are there. I'm less sure about the Pueblo Indians. I took the info from the DOE at face value and it gave the sentence more geographic diversity. There are many cliffs to choose from but southern facing cliffs stay comfortable. I'll find some better sources.

The DOE document states: "The Anasazi cliff dwellings demonstrate passive solar design." The Puye Cliff Dwellings and Gila Cliff Dwellings are also south facing. The cave dwellings in China also predominately face south.[[19]][[20]]

Link many more terms in the intro passive design, Sustainable architecture, climate, wave power, wind power, hydroelectricity, biomass, Passive solar lighting etc etc.

Done

Personally I would remove the referencing in the intro, I don't imagine the 2 cited bits are particularly controversial so provided they appear later in the article they can be cited there. JMiall ₰ 18:44, 14 May 2008 (UTC)

Removed

I removed the refs but now I'm reconsidering. What is the basis of the no ref guideline? I looked at some journal articles and noticed they use refs in intros. Approximately half the FA pages I reviewed (5/10) had refs. I would like to know what the purpose/goal of no refs in intro is.Mrshaba (talk) 00:34, 16 May 2008 (UTC)

The answer should be obvious. The lead is a summary of the article, meaning it is a duplication of information that is presented in detail elsewhere, with references. The only time it is appropriate to put references in the lead is if you wish to include something that you know is controversial and likely to be challenged - it allows looking up the reference directly without looking through the article to see why it is supported. Normally it is best to avoid such material in the lead, and only include it if it is essential to the article. 199.125.109.80 (talk) 00:17, 20 May 2008 (UTC)

I think instead of trying to create a sentence that includes all the terms that need to be linked in the intro, it would make the article more readable if they were in the form of a list, like they were last year. 199.125.109.80 (talk) 00:21, 20 May 2008 (UTC)

Concentrator photovoltaics

I moved and wikified this article a bit, but needs to be expanded and have spam removed. I think the article should ultimately stay as the subject is growing significantly. - Roy Boy 23:39, 16 May 2008 (UTC)

Peer review

Here are some bot-generated suggestions and my take on them.

Consider adding more links to the article; per Wikipedia:Manual of Style (links) and Wikipedia:Build the web, create links to relevant articles.^[?]

I've removed a number of links that were mostly generic geographical links. If possible links should be added that relate to the topic.

Per Wikipedia:Manual of Style (numbers), when doing conversions, please use standard abbreviations: for example, miles -> mi, kilometers squared -> km², and pounds -> lb.^[?]

There are a few hanging conversions I'd like to remove. The other option is to give conversion to ALL the metric units. That would be messy on this page but I'll follow the guidelines of the MoS if these conversions are required. I've chosen to use a joule convention where possible. This choice is driven by the need to simplify comparisons between electricity (watt-hours), thermal (watt-thermal), insolation (watt-hours per square meter) and energy density (joules per kg).

I finished these conversions. There isn't a crystal clear guide. See the discussion:here.

Per Wikipedia:Manual of Style (numbers), please spell out source units of measurements in text; for example, the Moon is 380,000 kilometres (240,000 mi) from Earth.^[?] Specifically, an example is . KG.

The KG example is in the references. I'm not sure how to institute this recommendation.

Per Wikipedia:Manual of Style (headings), headings generally should not repeat the title of the article. For example, if the article was Ferdinand Magellan, instead of using the heading ==Magellan's journey==, use ==Journey==.^[?]

Suggestions? I changed the Research institutes and Association names to comply with this. The "Solar" sections could also potentially all be shortened to Thermal, Chemical, Electricity etc.

Not really appropriate. Solar electricity is important to differentiate it from other types of electricity - it would not be obvious otherwise which type of electricity was being discussed. 199.125.109.57 (talk)

Per WP:WIAFA, this article's table of contents (ToC) may be too long – consider shrinking it down by merging short sections or using a proper system of daughter pages as per Wikipedia:Summary style.^[?]

I asked Johnfos if the Research institutes and Association section could be moved into the List of renewable energy organizations page. This would remove five lines of the ToC and could help. I removed the Books and journals subsection of the References section. The Process heat section can probably be merged into other sections.

Simplest solution is to move the Solar thermal subtopics to the solar thermal article, which has been done. This article is now a useless duplication of information, and horrendously long as a result. Some of the other subsections with subarticles can also have shorter summaries, and none should have subsections to summarize subarticles. 199.125.109.57 (talk) 23:18, 8 May 2008 (UTC)

This suggestion does not jive with the FA 1b. "Comprehensive" criteria. Solar energy is heat and light. Solar thermal technologies represent over 90% of the 'solar' technologies on a GW basis. I moved the Research and Industry associations over to the RE list.

Please ensure that the article has gone through a thorough copyediting so that it exemplifies some of Wikipedia's best work. See also User:Tony1/How to satisfy Criterion 1a. You may wish to browse through User:AndyZ/Suggestions for further ideas.

Working on it. Mrshaba (talk) 19:51, 8 May 2008 (UTC)

Please let's not remove geographical links unless we are sure that it is good practice. I usually link every geographical term on first reference. I also volunteer to give the article a good copy read, but it won't be till the second half of next week. Itsmejudith (talk) 19:54, 9 May 2008 (UTC)

I added back several geographic links today (Portugal, USA, Germany). Many places don't have links though: Japan, Israel, Netherlands, Chile, Brazil, Cameroon, Uzbekistan, etc. I have two concerns with geographical links. I think we should avoid stringing them together if possible. I'd also like to avoid linking to locales that don't have articles - Ein Bokek is an example.

That's really good. Agreed that we shouldn't create red links just to small places. Countries should be linked on 1st mention I think. Itsmejudith (talk) 21:00, 9 May 2008 (UTC)

You were right Judith. I'll fix all the Geographical place name links. Link guidelines Mrshaba (talk) 17:52, 23 May 2008 (UTC)

Intro

I reworked the intro and moved some material around. The current version will no doubt need more work but it more closely approaches the goal of summarizing the page. At this point I think the "solar power" blurb definitely needs to be expanded to balance things. Suggestions? Mrshaba (talk) 01:03, 17 May 2008 (UTC)

Go edit some other articles for 6 months. Quit messing up this one. Not to be rude of course, but the lead needs to have three paragraphs, not one.

Change "or" to "and": "Solar power is a synonym of solar energy or refers specifically to the conversion of sunlight into electricity by photovoltaics" should be "Solar power is a synonym of sola r energy and refers specifically to the conversion of sunlight into electricity" (it is not specifically by photovoltaics). 199.125.109.80 (talk) 20:08, 19 May 2008 (UTC)

What call is there for this incivility towards an editor who is putting in a lot of work on this article? I rewrote that sentence and stand by the "or". Itsmejudith (talk) 22:35, 20 May 2008 (UTC)

The two meanings are not mutually exclusive, hence or is not appropriate. 199.125.109.41 (talk) 01:05, 21 May 2008 (UTC)

On one occasion of usage it has one of those meanings: the broad one or the narrow one, hence or is more appropriate than and. Itsmejudith (talk) 15:57, 21 May 2008 (UTC)

You've lost me. I have no idea what you mean by broad/narrow, or one occasion. 199.125.109.43 (talk) 18:37, 21 May 2008 (UTC)

Easier to just go back to a better version of the intro. 199.125.109.43 (talk) 18:39, 21 May 2008 (UTC)

PV history

Source - EIA Mrshaba (talk) 18:54, 19 May 2008 (UTC)

Source - Production number 1975-2003 Mrshaba (talk) 04:23, 21 May 2008 (UTC)

Source - $/Watt numbers Mrshaba (talk) 04:29, 21 May 2008 (UTC)

Source - Deployment Mrshaba (talk) 00:58, 24 May 2008 (UTC)

Types of Technologies note

This note is used on the Renewable energy in Scotland page. Something like it could be useful for this page.

Note on 'installed capacity' and 'potential energy'. The former is an estimate of the maximum productive output of a given technology or individual generation station at a single point in time. The latter takes into account the likely intermittency of energy supply and is a measure of output over a period of time. Thus, for example, individual wind turbines may have a 'capacity factor' of between 15% and 45% depending on their location, with a higher capacity factor giving a greater potential energy output for a given installed capacity. The 'potential energy' column is thus an estimate based on a variety of assumptions including the installed capacity. Although 'potential energy' is in some ways a more useful method of comparing the current output and future potential of different technologies, using it would require cumbersome explanations of all the assumptions involved in each example, so installed capacity figures are generally used. Mrshaba (talk) 20:24, 23 May 2008 (UTC)

Possible source: [www.rff.org/Documents/RFF-DP-04-19REV.pdf] Mrshaba (talk) 21:44, 23 May 2008 (UTC)

"Potential energy" is not a good term to use at all, because it has a totally unintended meaning - potential energy is one of the two types of energy, kinetic and potential. What was intended, I think, is "potential total annual energy". Instead of that mouthful, just use "generated energy". 199.125.109.134 (talk) 01:33, 24 May 2008 (UTC)

How Do I Indicate An Inconsistency?

How do I indicate an inconsistency in the article?

In this particular article the inconsistency is in the final paragraph of the "Energy from the Sun" section. It states that the annual average insolation in the US is "10.8 to 32.4 MJ/m²/day" and that "typical solar water heating systems operating at 60% efficiency will deliver 4.85 to 14.5 MJ/m²/day".

4.85 and 14.5 represent 40% of 10.8 and 32.4, respectively, not 60%. So either the percentage or the final numbers are wrong. I suspect that it is the 60% which is wrong since most solar water heaters that I've found have efficiencies around 30%, but without a good source to cite I don't want to risk compounding the error.

Instead, I'd just like to flag the information as being inconsistent so that anyone reading the article will exercise caution when using those numbers. Is there a way to do that? —Preceding unsigned comment added by [email protected] (talk • contribs) 05:44, 20 May 2008 (UTC)

I'll recheck the numbers but the source I used clearly indicates the operating range of several types of solar water heaters in the 60% range. These numbers are always dependent on operating temperatures - i.e. the higher the delta T the less the heat transfer. I'll look for another source. Perhaps something that reflects the performance of water heaters in China where most of these are installed. Mrshaba (talk) 06:13, 20 May 2008 (UTC)

Try Israel. I believe it is said that 100% of homes in Israel have solar water heaters installed. 199.125.109.80 (talk) 20:57, 20 May 2008 (UTC)

Large numbers also in Greece. Itsmejudith (talk) 22:32, 20 May 2008 (UTC)

This source indicates an overall efficiency of 50% for three categories of water heaters described as low, medium and high temperature. The source is a little over 10 years old so it's safe to assume there's been some performance improvement. EIA Mrshaba (talk) 05:14, 21 May 2008 (UTC)

Possibly, but that is not an adequate source for saying it is 60% now. 199.125.109.43 (talk) 18:34, 21 May 2008 (UTC)

One possible way to bypass the need to compare efficiencies would be to compare areas occupied by and energy generated by the two technologies on a worldwide basis. I know of a source that lists occupied area for SHW and energy generated by both SHW and PV. That leaves finding the occupied area of PV worldwide. Just a thought. Mrshaba (talk) 00:31, 24 May 2008 (UTC)

"10.8 to 32.4 MJ/m²/day" is too wide a range. Where did you find a location with 32.4 MJ/m²/day? The highest the other reference shows is 21.5 in Honolulu. 199.125.109.136 (talk) 09:54, 26 May 2008 (UTC)

For example, the second reference states: 199.125.109.136 (talk) 10:03, 26 May 2008 (UTC)

You may compare you location to the following two extreme locations.

Average annual insolation levels:

Central Australia = 5.89 kWh/m2/day - Very High [21.2 MJ/m²/day]

Helsinki, Finland = 2.41 kWh/m2/day - Very Low [8.7 MJ/m²/day]

Making the installed capacity of solar thermal collectors comparable with that of other energy sources, solar thermal experts from 7 countries agreed upon a methodology to convert installed collector area into solar thermal capacity at a joint meeting of the IEA SHC Programme and major solar thermal trade associations, that was held in September 2004 in Gleisdorf, Austria. The represented associations from Austria, Canada, Germany, the Netherlands, Sweden and the USA as well as the European Solar Thermal Industry Federation (ESTIF) and the IEA SHC Programme agreed to use a factor of 0.7 kWth/m2 to derive the nominal capacity from the area of installed collectors.2003 Report

This metric gives a nominal peak efficiency of 70%. The nominal peak efficiency is what's being compared in the blurb. I calculated the worldwide average performance of SWHs at about 4 MJ/m2/day and PV at about 1 MJ/m2/day. The two metrics of comparison (nominal efficiency or MJ/m2/day) scale well so either will do. Mrshaba (talk) 22:39, 30 May 2008 (UTC)

Clotheslines

Clotheslines are not necessarily a solar energy technology. In any given situation, the process of drying clothes is driven by the humidity of the air and air movements as well as sunlight. We call it air drying for good reason. I think a more specific blurb on "solar washing and drying" belongs in the process heating section. Mention that 90% of the energy used for washing clothes is for heating the water and washing clothes accounts for 2.6% of the total residential energy use. Drying clothes uses X% of the electricity and X% of the natural gas in the US. The blurb could mention drying racks, clotheslines and other notable solar drying technologies such as desiccant systems. [21] [22] Mrshaba (talk) 21:35, 26 May 2008 (UTC)

Wrong. Clothes lines are an essential element of solar energy. Do clothes dry as fast at night as they do during the day, or when the sun is behind the clouds? Why would that be? Oh my, it is because of the sun. It definitely is not a process heat application, because most of the energy is not heat that dries the clothes. Using clothes lines, like were common in the 19th century, would save 5 to 10% of electricity used in the United States. Just a link to clothes line is sufficient. This article definitely does not need to go into details about laundry... 199.125.109.136 (talk) 22:15, 26 May 2008 (UTC)

Clotheslines can be used indoors. They are not inherently a solar technology. The connection needs to be made because all the technologies on the page are direct energy technologies. I see nothing wrong with including a short blurb about laundry because this is a high energy use area and there are competing solar technologies to replace this energy use. The water heating aspect of laundry is covered within the water heating section but the dryer portion is missing. Process heat seems to be an appropriate area for inclusion.

In 2005 clothes drying used 66 billion kWh and accounted for 5.8% of national energy consumption. [23] These numbers exclude the use of natural gas which is used by about 20% of dryers.Mrshaba (talk) 03:02, 27 May 2008 (UTC)

Wrong again. Clothes lines are outside. Clothes drying racks (Clotheshorse) are normally used indoors. It's two different technologies. While clothes will eventually dry outside without the sun on a line it is solar energy that really does the trick, and the article is way too long as it is to add a paragraph about laundry. Once again it isn't the heat that dries the clothes, it is radiant energy and the wind. So yes a clothesline outside in the shade that never sees the sun can still be used to dry clothes, but it is the sun that really does the work, and that's where proper setting comes into play - given two choices, in the front of a house in the sun or in the back of the house in the shade - the choice is yours, make it work effectively or hide it (be stupid and posh or smart and savvy). But I really don't want even a short blurb, because I don't think it is warranted, but I do think that it is essential to have a link and mention this important technology. Saving 66 billion kWh per year is nothing to sneeze about. How many years will it be before the US generates 66 billion kWh from photovoltaics? Yet for a few yards of rope it could generate the equivalent from the sun within a week. 199.125.109.121 (talk) 04:30, 27 May 2008 (UTC)

I don't think I'm wrong. Although generally used outside, clothes lines can be used effectively inside. 1, UK, Australia, NY Times. In general this isn't considered a solar energy technology and seems to be more associated with wind and air. The Solar Energy journal covers clothes lines only once which is strange considering how energy intensive drying is and the fact that the journal covers both direct and indirect solar resource applications. Despite all this, the technology seems to deserve a short blurb mentioning energy use, the Right to Dry movement and the various types of clothes drying techniques. The research is already out of the way which is nice. See also laundry list Mrshaba (talk) 07:26, 27 May 2008 (UTC)

Knock yourself out. You know what my thoughts are about the length of this article. You do realize, though, that the three paragraphs you have written would almost double the length of the clothesline article, and increase the number of references by six, to a new grand total of six (in other words it doesn't have any now). As to air and wind, I'll take ten minutes of sun any day over an hour of 60 mph wind and air. Try drying a pair of denims in a dryer set to air only and you will see what I mean. 199.125.109.77 (talk) 21:38, 28 May 2008 (UTC)

Short paragraphs

The batteries of electric bicycles may be charged from solar-generated electricity; alternatively a PV panel may be located on the bicycle itself.

The idea of solar-generated electricity powering vehicles could go into an introductory blurb. The vehicle section might need one anyway because we need to be more explicit about the experimental nature of solar vehicles.

Active solar cooling can be achieved via absorption refrigeration cycles, desiccant cycles, and solar mechanical processes. In 1878, Auguste Mouchout pioneered solar cooling by making ice using a solar steam engine attached to a refrigeration device.^[3]

see Absorption refrigerator Mrshaba (talk) 00:43, 3 June 2008 (UTC)

During 2006/2007, solar assisted cooling attracted increased interest for a variety of commercial and industrial buildings; some dozens of large-scale systems (i.e., 100–500 square meters) entered service in Europe, mostly in Germany. Sarasin (2007) reported around 40 systems in service in Europe solar-assisted air conditioning of buildings, with total capacity 4.4 MWth. See IEA/RETD (2007) for a comprehensive report on the subject. Mrshaba (talk) 23:13, 23 May 2008 (UTC)

Concentrators can be used in the gasification of feedstocks such as coal, municipal solid waste and crop-grown biomass. The resulting hydrocarbons can be used to synthesize so-called "sunfuels".

This blurb can be merged into the S2P blurb somehow.

Concentrating solar technologies can also be used in the production of industrial chemicals. A prototype 10 kW solar furnace at the Paul Scherrer Institute produced lime at 64.2 g per minute with a solar energy to chemical energy efficiency of 34.8%.^[4]

The process heat section should mention solar furnaces. This info can be trimmed and used as one of a few example there.Mrshaba (talk) 16:58, 14 May 2008 (UTC)

A food processing facility in Modesto, California uses parabolic troughs to produce steam used in the manufacturing process. The 5,000 m² collector area is expected to provide 4.3 GJ per year.^[5]

The blurb could be expanded by mentioning some other solar trough process heat projects and giving a basic explanation of operation.

Rough draft doneMrshaba (talk) 20:23, 20 May 2008 (UTC)

Order of mag error in wordlwide electricity gen.

NB: This change needs to be made by someone with enough privileges to edit. I have no access to change this page.

The source [12] gives the figure of worldwide electricity production of 15746.54 billion kWh. Since 1 kWh = 1000 W × 3600 s = 3.6×10⁶ J, the figure in question is 15746.54×10⁹×3.6×10⁶ = 56.68754×10¹⁸ J, or 0.05668754 ZJ. The article lists 0.00567 ZJ, which is one order of magnitude less, and needs to be changed to 0.0567 ZJ.

I also confirmed that worldwide energy consumption per [13] is right. I did not compare any other figures in the article to those in its sources, however.

— Fregimus (talk) 09:05, 31 May 2008 (UTC)

That error was made by Mrshaba with this edit.[24] 199.125.109.31 (talk) 13:57, 31 May 2008 (UTC)

{{editprotected}} Please change 0.00567 to 0.0567 in the Energy from the Sun section. 199.125.109.31 (talk) 14:03, 31 May 2008 (UTC)

Please also unprotect this page so that we can edit it ourselves. The page was inappropriately protected to allow one editor to edit and not another. 199.125.109.31 (talk) 14:04, 31 May 2008 (UTC)

Good catch. Mrshaba (talk) 19:05, 31 May 2008 (UTC)

Only half done. The page is still protected, and needs to be unprotected. 199.125.109.134 (talk) 08:48, 3 June 2008 (UTC)

Daylight saving time

I was asked to look into daylight saving time and its relation to this article. I just now saw the text in #Moving and removing content and have the following thoughts:

That study is old (2001) and its conclusions are dated. I suggest the following more-recent citations:

Myriam B.C. Aries; Guy R. Newsham (2008). "Effect of daylight saving time on lighting energy use: a literature review". Energy Policy. 36 (6): 1858–1866. doi:10.1016/j.enpol.2007.05.021.{{cite journal}}: CS1 maint: multiple names: authors list (link) This is a reliable recent review which says that recent research is limited and reports contradictory results.
Adrienne Kandel; Margaret Sheridan (2007-05-25). "The effect of early daylight saving time on California electricity consumption: a statistical analysis" (PDF). CEC-200-2007-004. California Energy Commission. Retrieved 2008-03-08. {{cite journal}}: Cite journal requires |journal= (help)CS1 maint: multiple names: authors list (link) This study is by the same group that did the 2001 study. It says the earlier DST in 2007 had little or no effect in California.
Matthew J. Kotchen; Laura E. Grant (2008-02-08). "Does daylight saving time save energy? evidence from a natural experiment in Indiana" (PDF). Preliminary Program. Environmental and Energy Economics Program Meeting. National Bureau of Economic Research. Retrieved 2008-03-03. {{cite conference}}: External link in |conferenceurl= (help); Unknown parameter |booktitle= ignored (|book-title= suggested) (help); Unknown parameter |conferenceurl= ignored (|conference-url= suggested) (help)CS1 maint: multiple names: authors list (link) This examined billing data in Indiana and found that DST increased residential energy consumption by 1% to 4%, primary due to extra afternoon air-conditioning.

For more studies and details, please see Daylight saving time#Energy use.
It's probably overkill to cite all this stuff here. Aries & Newsham is the best citation, since it's a review (not just a single study). To help try to improve things I made this change to incorporate its results. Hope this helps.

Eubulides (talk) 05:34, 3 June 2008 (UTC)

Moving and removing content

This section has been set up to discuss and propose moving content off the page. Mrshaba (talk) 15:41, 21 May 2008 (UTC)

Just do it. No discussion needed. Just leave a summary in the main article and copy it to the subarticles. Just don't delete anything. It helps if you do the copy before the delete because this is a high trafficked site and you don't want someone clicking on it and at that moment not finding what they are looking for. Better to for a few seconds have a duplication of information than for a few seconds/few minutes have information missing. 199.125.109.43 (talk) 18:33, 21 May 2008 (UTC)

Daylight saving time (DST) utilizes solar energy by matching available sunlight to the time of the day in which it is most useful. DST shifts electricity use from evening to morning hours thus lowering evening peak loads and the higher costs associated with peaking electricity. In California, winter season DST has been estimated to cut daily peak load by 3% and total electricity use by 12,250 GJ.^[6] DST has been estimated to reduce early spring and late fall peak loads by 1.5% and total daily electricity use by 3,600 to 11,800 GJ.^[6]

I calculated the effect of DST on California and came of with 553 GWh out of a total of 283,000 GWh of electricity consumed annually. I had thought the number was closer to 1-2% of electricity consumption rather than one-fifth of one percent. The DST paragraph was also questioned by the peer review. I added this information originally but now I think it needs to go. Any objections? Mrshaba (talk) 21:47, 30 May 2008 (UTC)

See revised blurb and comments below by Eubulides. Mrshaba (talk) 16:56, 6 June 2008 (UTC)

I think CSP needs to stay. These are some of the oldest and most industrialized solar technologies. They are important to the weight and balance of the article given their history and current development. The CSP technologies are covered in more depth in the Solar thermal energy article. In my opinion a sub-article covering these technologies specifically should be called Concentrating solar thermal (CST) or Concentrating solar power (CSP) per their general naming conventions. The page is currently about 41 kb of readable prose. This length does not require breakup. See Article size Mrshaba (talk) 16:56, 6 June 2008 (UTC)

Please don't bite the newbies. This article needs more than one editor, more than two, more than ten. Please don't revert just because someone makes a good faith edit.[25] You think there is any chance of someone helping with the article when they get treated like that? The material removed is covered in the subarticle and does not need to be duplicated here. There was nothing wrong with the edit, and it certainly helped with the size. When you are on dialup, which last I checked was true of at least half of the world, edit byte count is far more important than readable prose. In any case 41 kb is pretty long for readable prose. It is better to use summary style, which is just what you reverted. Apteva (talk) 11:57, 7 June 2008 (UTC)

As you know, the edit byte count argument has been rejected on the Article size talk page and it doesn't need to be carried on here. I'd like you to drop this argument and remove your call for major trimming. It is fair to ask for discussion before moving and removing several paragraphs. FA articles are thorough and CSP is an important technology that deserves inclusion. Summarizing the individual technologies in 4 or 5 sentences seems to give them proper weight. Mrshaba (talk) 19:56, 7 June 2008 (UTC)

The best way to include it is just to introduce it and make a {{main|Subarticle}} link to it. Articles should not attempt to pull everything out of subarticles and put them into the main article, but instead should do the opposite, pull things out of the main article and put them into subarticles. Which is better a 10 megabyte main article that has links to 100 subarticles that are each 100 k, or a 10 k main article that has links to those same articles? In both cases the exact same information is presented. In the first case it is all duplicated and the main article is impossible to open, in the second case the main article opens in about a second and can be quickly used to find the detailed information in the subarticle. The reason why Wikipedia has chosen the latter, known as summary style, is that it works better for an encyclopedia, where many people are just looking for one factoid, and do not wish to read the entire article. Apteva (talk) 15:17, 10 June 2008 (UTC)

The 4 or 5 sentence blurbs are good summaries. These concentrating technologies specifically deserve to be mentioned on this page because they produce utility scale electricity and have for a long time, they show different reflecting geometries that aren't mentioned anywhere else on the page, and they have wonderful pictures which add to the quality of the page. The material has been here for many years so there have been many thousands of page visits without complaint. Your desire to break up this article is a desire seemingly separate from the article itself. You seem to be looking at it from an information management point of view rather than a content point of view and I think you've got it backwards. The content should show you how to manage the information. The size of the article is just about right. Mrshaba (talk) 17:12, 10 June 2008 (UTC)

You are entirely entitled to your point of view, which I believe is based on viewing it from a broadband account and not from dialup, which is 25 times slower. I am not advocating that the article be 25 times smaller, however, only 2 times smaller. I have no objections to a few sentences about an important technology, although the approach should have been to revise the summary and not just revert it.[26] The intent is to summarize the entire subarticle, not every portion of it. I really can not see the need for subsections in summaries. Apteva (talk) 19:17, 10 June 2008 (UTC)

Moving and removing content (Post Adacore)

Adacore trimmed, truncated, and/or moved some detail oriented info. Following this mindset I'm moving similar info here.

A molten salt storage system consists of a salt loop connected to an insulated storage tank. During the heating cycle, the salt mixture is heated from an initial temperature of 290 °C up to 565 °C. During the power cycle, the salt is used to make steam for a thermal power station. Mrshaba (talk) 03:27, 14 June 2008 (UTC)

I plan to replace/alter this info. The basic issue here is that unsubsidized PV electricity is more expensive than conventional electricity in all but remote areas or island markets such as Hawaii and Japan. We can mention grid parity locations but we should not exaggerate the economy of PV. Per Adacore's suggestion, I plan to add a table that lists levelized costs of PV in comparison to other energy technologies. This value will not include subsidies, incentives etc. Preliminary research indicates the value will be around 20-40 cents/kWh.

Photovoltaic electricity is now competitive with conventional electricity rates in many locations. Due to sale of renewable energy credits and other incentives, Nellis Air Force Base is obtaining photovoltaic power for about 2.2 cents/kWh and grid power for 9 cents/kWh.^[7] Typical payback periods for installing photovoltaics are 15 to 25 years.^[8] Photovoltaic production growth has averaged 40% per year since 2000 and installed capacity reached 10.6 GW at the end of 2007.^[9] By 2006 more polysilicon was used for photovoltaics than for computer chips.^{[citation needed]} Mrshaba (talk) 04:05, 14 June 2008 (UTC)

Approximately 14% of the total energy used in the United States is for water heating.^[10]
Worldwide, solar water heaters annually deliver approximately 600 kWh per kW installed.
The 0.25 EJ produced by solar water heaters worldwide in 2006 compares to 4.1 EJ used annually to heat water in the U.S.^[9]^[11]

Trimmed info. Mrshaba (talk) 23:23, 14 June 2008 (UTC)

Images

If you would like to propose an alternate image, be my guest. However I do not know of one that does the job as good as the ones used. As to discrepancies, I see none. The article adds surface radiation of 89 PW to atmospheric absorption, 33 PW, to get 122, which is converted to 3850 ZJ. 33 PW is not inconsistent with the 870 TW that the wind includes. You want to explain your confusion? What you are doing in the article, however, is jumping around a lot between total energy for the sun and potential energy from the winds, which is totally comparing not only apples and oranges, but ripe apples with rotten oranges. If you would like to switch to other images, just remember the guidelines, one that shows an earth based application of solar energy, and one that shows the potential for solar energy. Apteva (talk) 00:05, 4 June 2008 (UTC)

The box lists a flux of 86 PW. The page lists a flux of 89 PW. Mrshaba (talk) 01:49, 4 June 2008 (UTC)

Well that is hardly an order of magnitude. If you look at the reference you will see that the older version used 89 and the current version states that it gets updated as assumptions change. 199.125.109.136 (talk) 02:16, 4 June 2008 (UTC)

89 PW in one place and 86 PW in another is a discrepancy. Energy vs exergy is the discrepancy that underlies all of the information in the box diagram vs the page. The wind flux listed in the box is off by an order of magnitude from the wind potential listed on this page and the wind power page. The external ref listed for the box diagram blurb is also dead. The box diagram has already gone through an RfC which favored removing it for a higher quality picture. I've let it slide for the most part because I'm sure as the page makes the run to FA these things will work themselves out. Mrshaba (talk) 03:05, 4 June 2008 (UTC)

You have a major discrepancy in listing 3850 ZJ for solar and 2.25 for wind as one is total flux and the other is available potential at a specific height and location. I was just going to remove the wind line item, but figured if it shows the height it was for readers would get a clue that it doesn't include the jet stream for example, which is included in the 870 number. There is nothing wrong with the cube figure, it's a good image - every time you take it out someone else puts it back. You are splitting hairs over things that are a mile wide. It's pointless. Apteva (talk) 03:36, 4 June 2008 (UTC)

The immediate problem with the box is that it conflicts with information on the page - both text and the other diagrams with stronger corroborating sources. As to the discrepancy, each bullet is given in context with a source. Smil and NASA use similar fluxes. There is no way to compare everything symmetrically. Primary energy use does not compare 1:1 with electricity generated from wind or PV. These things are beyond the scope of this page. Mrshaba (talk) 05:26, 4 June 2008 (UTC)

You need to be specific about what you are talking about. 86 and 89 and not significant differences. Neither is a number that is usable for any real purpose. Does it matter that one indicates that we only need to use 0.0174% of available sunlight to power all our needs and the other that we only need 0.0169%? Not in the least. Intelligent people simply round it up to "less than 0.02%". We can easily harvest that or ten times that if we wish, or even 100 times. What you need to understand is that earth science is an approximation, it is not an exact measure; when we calculate how big a mountain is (not how tall but how much mass it contains), it doesn't matter if we are off by 5%, 10%, or even 20%, because no one is ever going to use the number anyway. Our job is not to look for exact numbers, but to report things as they are represented by available references. If someone in 2006 says 89 and someone in 2008 says 86 the best thing to do is show the source for each and refer to the number as approximate, which is exactly what has been done. You need to get over wanting everyone to use the same number for everything. Estimates vary, just leave it at that. By the way, solar can be expected to take an ever increasing bite out of primary use, as people switch from gasoline and diesel cars to plug in hybrid and electric cars, and as people switch from oil and natural gas heat to solar/electric heat in buildings. I would estimate that if the Chevy Volt or next gen Prius had a 40 mile electric range the only time most people would use any gasoline at all with them would be on the occasional weekend that they went away on a trip - for many only once or twice a year. Since the equivalent fuel cost of electricity works out to about $0.60 a gallon I would expect at that point that gasoline will drop to about $0.90 to remain competitive. It's all supply and demand - if there is no demand but plenty of supply, the price drops. If you have a car that you can fill up with whichever is cheaper, you wouldn't buy gasoline if it was more than about that price. Apteva (talk) 17:26, 4 June 2008 (UTC)

The box lists a flux of 86 PW. The page lists a flux of 89 PW. Congrats on getting an account. Mrshaba (talk) 17:55, 4 June 2008 (UTC)

Read the above. Who cares? Use the older Image:Available Energy-2.jpg if it matters that much to you. The newer one is much better, though, because it also includes geothermal, and all the numbers, for solar, wind and geothermal are all from the same reference. Apteva (talk) 21:51, 4 June 2008 (UTC)

I don't think either picture belongs on the page let alone the lead. This picture went through a two month long RFC from October-December 2007 and has gone on well past long enough since then. SEE: Rfc Pictures. Consensus was to remove the picture. This has been an incredible waste of time and effort. Mrshaba (talk) 19:58, 6 June 2008 (UTC)

Sorry to hear you so disappointed. Actually this is an important article that gets over a million page views each year, and on a topic that is becoming more important every minute. Solar grid connected PV is the fastest growing energy source in the world, and is an incredibly important replacement for dwindling oil supplies. Solar grid connected PV can easily replace home heating oil, automobile fuel, etc. In conjunction with wind power and hydro-storage, solar energy can easily meet all of our energy needs, 80% of which are currently met by oil. Oil which is selling at 5-6 times cost due to it running out soon. Just like the lemmings we came to a cliff and went right on over it, even though the solution was seen and the problem known thirty years ago, just as the dual problem of global warming was known thirty years ago. Another clue of the importance of this article is that it also exists in over 40 other languages. So no it has not been an incredible waste of time. However, to properly illustrate the article, the two lead images should be one that shows a typical application of solar energy and one that shows the potential for solar energy, which is just what we currently have. However it would be a huge improvement to replace the U.S. centric photo with one from one of the larger European solar power plants. Unfortunately we do not have any. Apteva (talk) 11:39, 7 June 2008 (UTC)

The Rfc indicated the box picture is undesirable for several reasons. There were 5 or 6 people that indicated negative views of the box diagram with you as the sole supporter. This is an ILIKEIT issue. Drop it. Mrshaba (talk) 15:38, 7 June 2008 (UTC)

No, it's an it makes sense issue. You might notice that during your wikibreak no one but no one objected to the lead images after they were restored, other than to tweak the size a little. Also, I took a look at all 45 sister language pages today and the vast majority use an application and/or an indication of the availability of solar energy. See for example de:Sonnenenergie and ca:Energia solar which used both. There were a few with none and a few that just used whatever we were using when their page was created. One used sort of a global warming diagram, and another used the spectrum of sunlight. So I fail to see any reason to deviate from what is most practical, and most popular for that matter - an image of an application and an image showing availability. Apteva (talk) 07:57, 8 June 2008 (UTC)

I'd suggest RfC except it's already gone to RfC. What's the problem with the picture of the Sun? Why are we making a big deal out of this? Itsmejudith (talk) 18:12, 8 June 2008 (UTC)

The sun doesn't illustrate the topic. Using it would be fine if there were no images available that actually show solar energy. As it is the commons category has 120 images and 20 sub-categories in all. Countless images that do illustrate the topic. We used the sun a couple of years ago but have gotten away from it now. Apteva (talk) 04:23, 9 June 2008 (UTC)

Er... Only a picture of the Sun shows solar energy, to the extent that one can show energy. Other photos show some ways that people use solar energy. It's entirely appropriate to start with the general and then move onto the particular. Itsmejudith (talk) 09:00, 9 June 2008 (UTC)

Isn't that what this article is about, the ways we use solar energy? Discussion about the actual energy of the sun are contained in other articles, such as sun and nuclear fusion. We didn't create the sun, but we did create solar energy, in the form of photovoltaics and many other applications. It is a broad topic, but there are iconic images that can be used, such as solar two (now decommissioned, oddly enough), or a large photovoltaic power plant. I would love to have someone take a photo of one of the larger photovoltaic plants. Over the next few years these will be in the hundreds if not thousands of megawatts, although thousands of megawatts is like trying to take a photo of a forest - you lose sight of the trees - closeups of SEGS are more effective than overhead views. Apteva (talk) 16:49, 9 June 2008 (UTC)

^ Lovegrove, Keith; Luzzi, Andreas; Soldiani, Iacopo; Kreetz, Hoger (2004). "Developing Ammonia Based Thermochemical Energy Storage for Dish Power Plants" (PDF). Solar Energy. 76: 331–337.
^ Thomas, George. "Potential Roles of Ammonia in a Hydrogen Economy" (PDF). {{cite web}}: Unknown parameter |coauthor= ignored (|author= suggested) (help)
^ Butti and Perlin (1981), p.72
^ Meier (2005), p.1355-1358
^ "Frito-Lay solar system puts the sun in SunChips, takes advantage of renewable energy". The Modesto Bee. Retrieved 2008-04-25.
^ ^a ^b Kandel, Adrienne; Metz, Daryl. "Effects of Daylight Saving Time on California Electricity Use" (PDF). California Energy Commission. p. 6. Retrieved 2007-11-08.
^ Nellis Air Force Base Solar Power System
^ "Supporting Solar Photovoltaic Electricity - An Argument for Feed-in Tariffs" (PDF). European Phtovoltaic Industry Association. Retrieved 2008-06-09.
^ ^a ^b "Renewables 2007 Global Status Report" (PDF). Worldwatch Institute. Retrieved 2008-04-30.
^ "R&D on Heating, Cooling, and Commercial Refrigeration". Department of Energy. Retrieved 2007-11-08.
^ "Buildings Energy Data Book: 1.1 Buildings Sector Energy Consumption" (PDF). Department of Energy. Retrieved 2008-06-13.

[1] Lovegrove, Keith; Luzzi, Andreas; Soldiani, Iacopo; Kreetz, Hoger (2004). "Developing Ammonia Based Thermochemical Energy Storage for Dish Power Plants" (PDF). Solar Energy. 76: 331–337.

[2] Thomas, George. "Potential Roles of Ammonia in a Hydrogen Economy" (PDF). {{cite web}}: Unknown parameter |coauthor= ignored (|author= suggested) (help)

[3] Butti and Perlin (1981), p.72

[Meier-4] Meier (2005), p.1355-1358

[5] "Frito-Lay solar system puts the sun in SunChips, takes advantage of renewable energy". The Modesto Bee. Retrieved 2008-04-25.

[California_DST-6] Kandel, Adrienne; Metz, Daryl. "Effects of Daylight Saving Time on California Electricity Use" (PDF). California Energy Commission. p. 6. Retrieved 2007-11-08.

[7] Nellis Air Force Base Solar Power System

[8] "Supporting Solar Photovoltaic Electricity - An Argument for Feed-in Tariffs" (PDF). European Phtovoltaic Industry Association. Retrieved 2008-06-09.

[Renewables_2007-9] "Renewables 2007 Global Status Report" (PDF). Worldwatch Institute. Retrieved 2008-04-30.

[10] "R&D on Heating, Cooling, and Commercial Refrigeration". Department of Energy. Retrieved 2007-11-08.

[11] "Buildings Energy Data Book: 1.1 Buildings Sector Energy Consumption" (PDF). Department of Energy. Retrieved 2008-06-13.

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