Wikipedia:Mediation Cabal/Cases/2006-07-12 Solar Updraft Tower

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Wikipedia Mediation Cabal

Article: Solar Updraft Tower State: Other Parties: (Content dispute) Mediated By: CP/M Comments: Practically complete, kept open just in case.

Contents 1 Mediation Case: 2006-07-12 Solar Updraft Tower 1.1 Request Information 1.2 Mediator response 1.3 Discussion 1.4 Compromise offers 2 JdH response 3 Flexme response 3.1 Wikipedia is not a soapbox 4 Proposed compromise

[edit] Mediation Case: 2006-07-12 Solar Updraft Tower

[edit] Request Information

Request made by: JdH 14:44, 12 July 2006 (UTC)

Where is the issue taking place?

Solar updraft tower

Who's involved?

Flexme

JdH

What's going on?

Flexme has recently revamped Solar updraft tower, taking out sections that are intended to give an unbiased review of the stengths and weaknesses of the technology, in effect transforming it into a company brochure of EnviroMission.

What would you like to change about that?

Revert to my Revision as of 23:11, 7 July 2006 and allow me to complete the task I had set myself to do, which is: bring that article to Wikipedia standards, further tightening the text by removing superfluous material, and develop a fair and unbiased presentation of stengths and weaknesses of the technology.

Would you prefer we work discreetly? If so, how can we reach you?

JdH_2006-07-12 AT hotmail DOT com

[edit] Mediator response

I've looked into the general situation about the matter. Curently it seems that both participants have views on the best layout and content for the article, and attempt to make it just the way they see it. This is what likely caused the conflict, and so we'll have to find some kind of compromise. Discarding useful additions is not the right way to resolve the problem, so let's expect the resolution might be not exactly what anyone of the participants wanted, but better than the other option. I suggest to state the reasoning in the discussion section, or just suggest compromises right now. CP/M 02:47, 13 July 2006 (UTC)

There's a suggested compromise version I'll post shortly; of course, it might be corrected, but corrections should be discussed. CP/M ^comm |Wikipedia Neutrality Project| 22:35, 29 July 2006 (UTC)

[edit] Discussion

my view is that this page is about this technology. the page about stirling engines should have details of stirling engines, and no details of "solar updraft towers" (isnt this what some one did a little while ago and messed it all up? they favoured enviromission - it was NOT ME, nor was it anyone i know or have ever communicated with, or been paid by, but i do respect your suspicion-this is important for wiki continuation). people interested in finding the highest percentage rate should find a link here to refer them in that direction. but they do not need the details of results.

consider this similar situation: imagine if all pages on all solar power devices not only had links to that which was most financially viable, but also a detailed discussion of exactly how viable the most viable method is (arguably enviromission) ... it would be an atrocious mess, almost all pages would be swamped one day by enviromission , and maybe dyesol the next, and then by another on another day. many wonderful ideas would be swamped and lose prospect of their own detailed consideration.

no technology deserves to miss out, each has their own space, and discussion of their own technology should dwarf anything else on their page. when we consider the updraft towers lack of abilty to convert 99% of incoming solar energy to electricity we should look directly at this issue. (have you seen my ideas in the discussion page of "solar updraft tower"? i have studied hydrodynamics at university, i was top of my class, i have loved it all my life ... this is not pap.) --Flexme 09:07, 13 July 2006 (UTC)

I agree with that. We need discussion of each technology to stay on its own page. Copying the same to several pages is harmful not only because of cluttering, but also because it tends to produce multiple versions of the same information, causing trouble with synchronisation. I'll check the articles on solar energy, but, if you can name any that have similar sections on the same technology (this or other), please list them.

By the way (just in case you haven't checked my user page), I'm myself a specialist in hydro/aero-dynamics, so if some technology detail should be mentioned, feel free to do that in the proper terms. However, I work in a very different field (one where 150 MW source can fit on a truck), and have no specific knowledge of solar towers at the moment. CP/M 12:02, 13 July 2006 (UTC)

the discussion here should be in depth about how and why this method suffers huge losses, and whether that is important to this process, it should discuss how it might be remedied, or perhaps it is intrinsic.

I'm not sure if you're suggesting we do critical assessments and analytical work... If so, these are valuable things to do, but not for Wikipedia articles, which need to be verifiable and not original research. There are other wikis that do accept analytical and original work - I'm quite interested in this myself, so if you want suggestions for other wikis, leave a note on my talk page. --Singkong2005 ^t_c 07:09, 16 July 2006 (UTC)

Yes, that would be better. It can be done on talk pages, to determine what information should be additionally verified and what should be linked, but articles should only be affected minimally, and in simple cases. CP/M 11:28, 16 July 2006 (UTC)

enviromission may be the lowest! but i have not seen a quote for this ... if it is it should be there.

my suggestion to make headway here, is to find one piece of information, and JDH and i agree on which page of wiki we think it is most sensibly located.

i would like to start with consideration of an overview of basic qualities of all solar power devices, qualities such as conversion rates, and unfortunatley, (yes i am a lot more idealistic than you suspect jdh), unfortunately financial viability, reliability, ease of access for poor nations etc etc ... i think the "solar power", or a similar central page, should have a complete list of all results. no other page should have it, (but every page of a solar powered device should have a detailed discussion of their own rate, and a discussion of their own position ... each page should discuss all details of their own technologies issues)--Flexme 09:07, 13 July 2006 (UTC)

Well, I'm glad there are common grounds, so we'll just have to discuss what exactly to do. Yes, the information about the technology would best be mostly contained within its page, while the central one should discuss all technologies.

As a sidenote, the estimated costs are very low, as 900M for 200 MW for a long time with minimal maintenance cost is cheap. Suspiciously cheap, actually, since the idea and technology is very primitive and safe, but require a lot of construction which cost is hard to estimate, but probably more than a billion. I'm not sure all the estimates are correct, as a huge solar power plant is very unlikely to be as cheap as nuclear. I suggest to find some outside analysis if it exists, or add a note that the costs are an internal estimate. CP/M 12:02, 13 July 2006 (UTC)

please expand this reasoning if you can; noone else can ?! ... i would like to know more ... .--Flexme 13:06, 13 July 2006 (UTC)

Well, it concerns some estimations on construction costs. The tower is going to be expensive, since the construction costs increase approximately as height^3.5, or even up to height^4. This means a 400-meter building is about 10-16 times more expensive than a smaller 200-m one. Even though the concrete tower is very primitive, the equipment for construction at 500 meters is not.

This is even more so with the greenhouse. For 38 sq.km. it would mean about just $10 per sq.meter. Not possible, at all. The glazing must be supported by a large metal structure. A 40 sq.m. metal and polycarbonate roof for a gas station costs no less than $15k. You can cut the costs ten times with mass construction, but the canopy is higher and must resist pressure, winds, hot moist air, other weather conditions, have good glass, for central part in two layers, and have reduced aerodynamic drag. Cutting it below $100/sq.m. is next to impossible, at least with glass, and it alone would count for 4 billions.

Such underestimations have happened before. For instance, the B-2 was supposed to cost just about $150M/unit, but real cost skyrocketed to ridiculous $2.2B, while maintenance requirements heavily restricted the use, and 40 billions went down the drain.

Something like this is very possible with the solar tower design. While it might be very productive if utilising excess heat from nuclear plants and energy-consuming industries, being a part of a large complex, on its own it's unlikely be effective. CP/M 10:17, 15 July 2006 (UTC)

i just want to add that nothing JDh has said semed like lieing or incorrect or offensive, jdh became very direct and BOLD, but it seems there is good justification given the history of this page. jdh has good info and it needs to find a home. when i came to this page looking for information about the tower i was swamped by information about other technologies and became a little hot headed ... i did a lot of editting in a 24 hour stretch (i had NEVER edited wiki before) before i made an account ... i was judged as a vandal by john at some stage, then he reinstated my edits, this gave me pause to reconsider and i made an account... this issue has caused me to begin editing wiki and hopefully i will continue at a smaller rate. i (hopefully) hold no grudge in any direction. i definitely feel i have found some friends.--Flexme 09:34, 13 July 2006 (UTC)

Some early mistakes in judjment certainly can happen sometimes, and people can be excessively suspicious after dealing with someone anonymous. This surely shouldn't become an obstacle in communication - so I guess we'll just resolve and forget the possible conflicts. The controversy isn't fundamental, so let's just find out what is possibly wrong in each other's edits, and find the right way. CP/M 12:02, 13 July 2006 (UTC)

[edit] Compromise offers

i feel good :) we need to find something which both you and i are happy with ( of course this is irrelevant if someone else moves elsewhere, my edits are there now ... is there a particular bad issue?).

Jdh, i do look forward to your continued contribution to wikipedia and our universe because i think you are well intentioned ;)--Flexme 12:32, 13 July 2006 (UTC)

something a little strange here: since this mediation began it seems that noone wants to edit the article ... surely jdh and i should hold back ... but, especially given that my (controversial?!)edits are presently there, i thought that everyone else should just cut loose and go for it!--Flexme 11:24, 16 July 2006 (UTC)

I for one have sat back to see the result, as I was uncertain if JdH saw me as part of the problem as I had tagged bits with {{cite needed}} and removed bits I saw as original research. His response was to flood me with references which were background, but did not contain the conclusions as far as I could see. --Scott Davis ^Talk 12:27, 16 July 2006 (UTC)

[edit] JdH response

I took on the task of cleaning up and revamping this article, and I have already spent a considerable amount of time and effort in doing so. I began that task starting from the Revision as of 06:42, 29 June 2006 by Onco p53. As that point in time the article contained a lot of duplication and other superfluous material, and I set out to clean up that overhead. Then, responding to a request of Scott Davis I spent several days researching the subject, to locate peer reviewed publications on the subject. Those several days of effort resulted in my Revision as of 23:11, 7 July 2006 by JdH. At that point in time I added a lot of new references, a new figure (borrowed from the French wiki), and some improvements in the description as well. Everything in the article was now well documented, including the portion Scott Davis labeled "original research". I considered this to be a Works in Progress; I meant to further tighten the text, and rearrange paragraphs to improve the flow of the article.
However, at that point in time there was an invasion of anonymous editors as well as Flexme who took out major portions of the text, including some very relevant sections; that was done without much justification, if any at all. Usually such disregard of the hard work of others is labeled "vandalism", and promptly reverted. The only reason I did not revert those edits is that I wanted to avoid a revert war.
Comparing the present version with my version of 7 July relevant sections that have been taken out include:

Comparison of the pilot plant in Spain with the dish-Stirling pilot plant at Sandia national lab (under Description)
A paragraph about "Carnot's theorem" and Betz' Law partially explaining the low conversion efficiency. (also under Description). This section is similar to one explaining the low efficiency of a solar pond.
The section "Evaluation" was removed almost entirely. It included a comparison of conversion eficiencies between the Updraft power plant and competing thermal solar power plants. Most of that material was already present before I started editing, but some of it I added just the day before, again in response to Scott Davis who was concerned about possible bias.
Also removed was a paragraph on land utilization; I planned to reduced that section to a single sentence saying that the Solar updraft tower needs 5× more land than solar troughs and dishes to generate the same amount of electricity.
Also removed are comparisons with existing and planned solar power plants around the world.

I think it is important, and in the spirit of Wikipedia to present the available data fair and square; it is not in anybody's interest to obfuscate relevant data simply because some people don't like it.
To resolve the present situation I am prepared to take on the task to come up with what I would consider to be a "Final" version. What I propose to do is, starting from the present version, to re-insert the sections that were improperly removed. What I also would do is rearrange things to improve the flow ot the article. If I take out material that is present in the present version I will provide a justification for that. In return for this gesture of good will I expect others to respect the hard work and effort that would take me, as well as the hard work that I have already put into impoving this article. JdH 14:54, 16 July 2006 (UTC)

My take on the WP:OR policy is that editors here must not combine information from several published sources to draw a new conclusion here. That is what I felt JdH was doing. I removed a sentence beginning "From those numbers it appears...". It was only after this that the Schlaich paper became cited. Much of the Evaluation and Competition sections appeared to be original evaluation and comparison against many other systems, and the whole article has a negative tone towards this technology. JdH was one of the proponents to merge a number of articles into this one, and prevent new articles on related concepts from being created. While this is ostensibly to reduce duplication of material, the effect has been to create duplication and disharmony in one place. Carnot's theorem appears out-of-place here, as it is about closed heat pumps. Betz' Law appears very relevent to the turbines. Any economic evaluation here is flawed — we should only be citing other's economic evaluations, as there are many local variables involved. Examples include the economic production value of the land without a solar collector over it, and assumptions about the value of the produced electricity. Much of Australia has its electricity consumption peak in hot summer afternoons caused by reverse-cycle air conditioners, not in winter as often occurs in the northern Europe and America.

Last time there was a discussion about merging articles, I proposed not merging, but to distinguish an article about science (what makes it work), one about technology and engineering (how to build one that works), and one about each actual project.

I still don't know what you mean by the obfuscate sentence, and you put it on my talk page, too.

I suggest that you work slowly, make a set of related changes in one or a few edits, then wait until the next day to do the next stage. It is hard to follow 50 edits at 2-minute intervals, and hard to critique or touch up an article that completely changes character with each edit. If necessary use {[tl|inuse}}. Edit summaries also make it easier to understand what you were trying to do. Since the article is clearly likely to get at least one major restructuring, propose the new structure on the talk page and wait 24 hours after the last comment before making the big change, taking into account what discussion occurs.

I'm not an expert in the field, so my edits are based only on what I can see in front of me. I want to read an article about the technology, not an article about how much better other technologies are. --Scott Davis ^Talk 05:36, 18 July 2006 (UTC)

[edit] Flexme response

the "solar tower" page has been moved to obscurity: "solar updraft tower" by user jdh; the page labelled of disputed neutrality by user jdh; the page of this technology plastered with propaganda from competition by user jdh; ... now emerges the truth : money rules. jdh seems to have helped win $57 million in funding for jdh's favoured group - just a few miles from enviromission: coincidence ?????? http://www.allheadlinenews.com/articles/7005311678

Comparisons between different methods of production of energy are VERY important to our world. They should be complete and thorough ... when we talk about land used we should also talk of the land used by coal power plants etc (they are the most important, and i hate them:( ) Comparisons are important ... where should comparisons be? Comparisons should include all issues: land, financial, ecological, aesthetic, Co2 production, renewability etc etc. Jdh's comparisons should be in here somewhere, right in the thick of the comparison analysis. If other comparisons have not yet been made then Jdh's analysis should be on its own waiting for the flood of other comparisons.

All results about the updraft tower should be on the tower page, and all the stirling engine results should be on the stirling engine page.

As for carnot and betz: applicability to this situation would demand that they are reinstated ... if you can convince me then i will be right behind you ... the only problem is that they seem to make ABSOLUTELY NO SENSE in this situation ... how can we resolve this? this seems to be a little more difficult ... even Scott(who is definitely not to be against the tower project) seems to think that betz is relevant, how do we find the truth?

Why am i so sure betz is irrelevant? Because the betz stuff is a very particular number applied to a very particular situation. It is the idealistic most productive scenario of a tall windmill in a paddock. This situation is nothing like what we have here. The assumptions made are as sensible as assuming that the tower is made of marshmellow, and that the sun is a giant tennis ball. Further, i have gone through a method of analysis, mostly based on verifiable wikipedia content, of the situation at hand ... and the huge losses seem to be mostly explained by the lack of height, AND WIDTH, of the tower.--Flexme 11:03, 20 July 2006 (UTC)

hi, its me again :) wow you dudes are getting into it! i had a quick skim through your stuff here ... i wish i had the time to be a part of the process, unfortunately i will have to leave it to you, at least for a while.Flexme 01:13, 12 August 2006 (UTC)

[edit] Wikipedia is not a soapbox

I would like Flexme and ScottDavis to take a very hard look at Wikipedia is not a soapbox. There is no shadow of a doubt that what you are trying to do is turn Solar updraft tower into a vehicle for propaganda and advertising of the Solar Tower® concept. I don't know why you are doing that; perhaps you are simply misled by EnviroMission propaganda; perhaps you have a direct stake in the Solar Tower®, eg as a stockholder of EnviroMission or a related enterprise. No matter what it is, you have to understand that what you are trying to do is clearly against Wikipedia policy. If you want to promote a "sympathetic point of view" for the Solar Tower® or propaganda for the Solar Tower® there are other ways of doing that, e.g. through Usenet or a blog or Wikinfo. But Wikipedia is not the place for it. JdH 18:38, 20 July 2006 (UTC)

I feel offended that you think I am trying to turn the article "into a vehicle for propaganda and advertising of the Solar Tower® concept." I have so far resisted saying that you (JdH) appear to be using it as a soapbox to criticise the concept. I am not any of the things you say, although you could possibly term me a "prospective stockholder" as I came to the article (then Solar Tower Buronga) to find out if they had started building it with the dual motivations of tourism and investment. I am surprised that you think my contributions sound like propaganda or advertising — can you show which ones?

What is excluded? says

An edit counts as original research if it proposes ideas or arguments. That is, if it ...

• [...]
• It introduces an analysis or synthesis of established facts, ideas, opinions, or arguments in a way that builds a particular case favored by the editor, without attributing that analysis or synthesis to a reputable source;

This seems to be what the large "comparisons" section did.

My understanding is that this article should describe the science, technology, implementation. Each other kind of power generation article should do the same. The reader may infer by comparing the descriptions that one kind is better than another according to that reader's value judgements of "better". Reputable sources may be cited to compare if necessary, but that might be better in an article such as Comparison of methods of energy production linked by {{see also}} from each relevant article. --Scott Davis ^Talk 03:15, 21 July 2006 (UTC)

You shouldn't be surprised or offended. You have made unwarrented claims that I had a bias against the Solar Tower. I have allowed you several weeks to retract that and apologize to me, and you have not done so; instead you keep repeating it. Because of that I decided to stop pussyfooting around, and be blunt about it.
The present version of the article is riddled with spam. A large part of the article is about promoting the trademark and concept of the Solar Tower®, about attempts by centain persons and companies to commercialize the concept, trying to get people around the world interested in building one of those, about a specific proposal from EnviroMission to built one of these in Australia, and their attempts to get private investors to invest in this enterprise. In summary: the article is abused to promote certain commercial interests, and as stated above: that is clearly against Wikipedia policy. What bothers me about it that not only did you allow others to put in promotional material, but you even reinforced that by putting a reference to EnviroMission in the very first sentence. I don't understand why you are doing that: either you don't recognize spam even when it is right in front of you, or you have a vested interest in it yourself.
People who read the Wikipedia article have every right to expect an unbiased POV, and not to be presented with promotional material. An unbiased view includes all relevant information: the good and the bad. You have made consistent attempts to filter out "bad" information, leaving behind the "good"; by doing so you helped create something that is biased in favor of the technology.
The clearest example of this is the discussion we have had about Carnot's theorem. Clearly, you are not a physicist yourself, and for someone who is not a trained physicist Carnot's theorem is pretty difficult to understand. That does not stop you from making strong statements that it does not apply. You keep repeating that, even after people who clearly know more about it have tried their best to explain it. For someone who does not understand the concept there comes a time that either you stay out of it, or you accept the opinion of people who know more about it than you do. To stubbornly keep repeating the same statement raises the suspicion that you have some alterior motive for doing so. It is pretty clear what it is: that paragraph about Carnot's theorem doesn't look good for the Solar Tower®, and therefore it has to go.
Another example of your bias is your stubborness in putting up those silly labels^{[citation needed]} and {{Original research}} on the information about conversion efficiency. Just putting on those labels doesn't make it so. In fact the information that the Solar Tower has a low efficiency were there all along; I didn't put it in. But you kept removing that important information even after I included more sources; in fact, those sources show that the information actually comes from Schlaich himself. JdH 16:09, 27 July 2006 (UTC)

It would be the best way for comparisons. If they aren't directly copied from sources, tables using data from a single source are OK; but comparing data from different sources should be done carefully. If everyone agrees, we could end the dispute on comparisons with this solution. CP/M (Wikipedia Neutrality Project) 12:34, 23 July 2006 (UTC)

Clearly, Wikipedia is not the place to make a lot of fuss about differences of a factor 2 or so; we better leave that to the commercial people. So I don't think that things like Cost of Energy should be discussed in the article. Only thing that may be worthwhile mentioning is that Wind turbines are the only source of alternative energy that is competitive right know.
But when there are differences in conversion efficiency of more than a factor 10 then that is clearly important. JdH 16:09, 27 July 2006 (UTC)

Yes, I put EnviroMission in the lead section, after you complained about the weasel words of "some people". I consulted on the talk page and received support for that part of the change. I attempted to reduce what I perceived as potential promotion by also adding the Spanish tower to the lead without discussion. I seek to end up with an unbiased document. Why shouldn't EnviroMission be mentioned? They appear closest to building a production tower from the references I have read. I know the Guardian article is old, and the citation notes its publication date. The reason I ask for sources to be cited is so I have a chance of reading them for myself, along with other readers. Why is it that nobody writes papers about how bad it is, if it really is as bad as you say? I'd expect to find stock advisors saying "don't touch this one with a ten-foot pole", but so far I have failed to find such reports. --Scott Davis ^Talk 23:46, 27 July 2006 (UTC)

I wish to further defend some of the remarks above. Wikipedia policy allows any user to remove uncited claims, optionally to the talk page. If I have marked something with {{cite needed}}, it is usually because I believe it, but want to check the source material. I have never used {{original research}} or {{or}} on any article - if I can't justify the claims, I've moved them to talk pages or deleted them with explanatory edit comments. If you look at my edit history on other articles, there have been cases where I have moved sections to talk pages, and I think even just removed them, some even referenced, but not with reliable sources. You clearly believe that you are more of an expert in the field of solar electricity generation than I am, which I have not disputed. However, just because my degree is not in Physics doesn't mean I can't contribute as a proofreader or fact checker.

Re the "spam" comment, Enviromission is presently named twice in the article—in the summary at the top, and in the section "Proposed solar tower projects". The other proposals are referenced by dated articles, but the proposers not named in this article. The two English-language references (a 3-year old press release and a 2-year-old news article) both refer to SolarMission, a 25% shareholder in EnviroMission. Are you requesting that a new sentence be introduced to say that a major shareholder in EnviroMission is proposing two of the others? You appear to regard papers by Schlaich highly. Is he related to EnviroMission in any way that you know of?

I think we both want to end up with a neutral article discussing the technology, but have different ideas of how to get there, and have each decided that the other is significantly biased, and are perhaps reacting to that. The way forward for all of us is probably to agree to treat each edit on its merits (regardless of who made it), and to proceed slowly enough that others have the opportunity to improve or comment as the article is improved from here. Can we get on? --Scott Davis ^Talk 15:32, 29 July 2006 (UTC)

[edit] Proposed compromise

There was proposed a version of article, which appears to be clean of particular bias. I suggest that everyone reviews it, and writes here what exactly sections he would like to insert or what to remove, with supporting arguments. CP/M ^comm |Wikipedia Neutrality Project| 22:48, 2 August 2006 (UTC)

The version is at Wikipedia:Mediation Cabal/Cases/2006-07-12 Solar Updraft Tower/Version1.

On the whole, it doesn't look too bad. Here's my critical copyedit comments. Some seek further info, some are just comments.

Content

• Intro is short, but OK. I'm uncertain if the last word in the second sentence should be chimney or (hollow) tower.

"chimney" is probably there because of historical reasons; at some point in time the concept was called a "Solar chimney". Most of the scholarly literature still uses that. But if you want to replace it by something else it is fine with me. JdH 16:59, 3 August 2006 (UTC)

"...large hollow tower or chimney." in the first intro and/or first paragraph of Description, then use chimney from then on. From a technical standpoint, "chimney" is correct, but from a common perception standpoint, chimneys are "bad". Explaining the use of the term is good. --Scott Davis ^Talk 14:59, 4 August 2006 (UTC)

I am puzzled why you think that "perception" would be relevant at all. "Chimney" is the more accurate description of the device, and is therefore the preferred term. Especially in view of the fact that it is commonly used in the scholarly literature. JdH 16:14, 4 August 2006 (UTC)

If you asked an ordinary person to describe a "chimney" the definition would likely include smoke or pollution: chimney, wiktionary:chimney [1]. I seek to ensure the introduction clarifies that this chimney is not releasing smoke and pollution, but merely controlling the thermals that glider pilots would find there anyway. --Scott Davis ^Talk 02:09, 5 August 2006 (UTC)

I think it is a mistake to follow in the footsteps of certain companies that seek avoid the word "chimney" in an attempt to promote the concept. What we should do instead is explain how this thing works, as clearly as we can. The problem with "Tower" or similar expressions is that it obfuscates how this thing works. Everybody knows by experience how a chimney works, and what its principle is; by calling it "Tower" instead nobody will understand how the heck this thing works. What about something like "warm air rises in a tall chimney"? JdH 13:19, 22 September 2006 (UTC)

• The description has lost the mention of specific heat capacity, and changed "tubes" to "hoses". Schlaic says "tubes or bags". The important point is "thermal storage", not specifically water.

I believe that "tube" is a Germanism (=literal translation of the German expression); the correct English terms is hose, as in firehose. JdH 16:59, 3 August 2006 (UTC)

To me, "hose" suggests flow, whereas this description appears to just be a heat-retaining material, which might later be replaced by some other substance if one is found/invented. I don't mind which term is used, just noticed it seemed odd. --Scott Davis ^Talk 14:59, 4 August 2006 (UTC)

Taking an unuasual step: look in the dictionary :-) The German word is Schlauch
flexible tube -- der Schlauch
hose -- der Schlauch
sleeving -- Schlauch
tube -- Rohr; Schlauch; Untergrundbahn
tube -- Schlauch
tubed -- mit Schlauch versehen
basically, it is one of those flexible tubes people use to water their lawn, stuff like that. What do blokes downunder call that? JdH 20:01, 4 August 2006 (UTC)

Yes, we water the lawn with a garden hose when the water restrictions let us :-) Sounds like "hose" is a reasonable term until we see what they actually put in one when (if) it is actually built. My interpretation of the description had been more like large black winecask bladders. I accept that may have been my own imagination. --Scott Davis ^Talk 02:09, 5 August 2006 (UTC)

• Chimney diameter should also be mentioned somewhere -Schlaic shows it's important in page 7 (and a lot wider than I had imagined).
• The sentence about Enviromission should have a reference, and perhaps mention that there are also proposals to build these in other places (or why those proposals have lapsed?).

There is already a wikilink to the EnviroMission article. In addition, a link to the EnviroMission website is included under External links.
AFAIK there are no concrete proposals anywhere else besides the Australian one; when I surfed for that all I found was an expression of interest, but no proposal anywhere. Do you have a reliable independent source for other proposals? JdH 16:59, 3 August 2006 (UTC)

The Spanish proposal appears to be at a similar stage to the Australian one, if I am correctly interpreting the output of Google Translators on these web sites: [2] [3] [4] --Scott Davis ^Talk 14:59, 4 August 2006 (UTC)

"prevé la instalación" means something like "... the installation is anticipated..."; that does not sound like a concrete plan at all. Without more specifics, like who will pay for it, which company will construct it and when they will start, details on government approvals, and all that it sounds more like a pie in sky kind of thing than a real proposal. It sounds disturbingly similar to the 2001/2002 1 km high tower in Australia that never got off the ground JdH 16:14, 4 August 2006 (UTC)

• Carnot's Theorem does not restrict the efficiency of conversion, it describes the theoretical maximum. There is still no reference to say how it applies. I have no doubt there is some sort of thermodynamic theorem that matters, I don't know if it's this one. I also expect some fluid dynamics are important, but appear to be almost dismissed in the last sentence of that paragraph.

what about "...provides an upper limit (or theoretical maximum) to conversion efficiency."?
The argument about the applicability of Carnot's theorem has already been discussed in detail on the talk page.
The wikilink to the Carnot article should suffice; there are further references there.
I don't think that fluid dynamics is all that important (or efficiency of the greenhouse for that matter); the main issue is the efficiency of the chimney itself. That is discussed in some detail in "Pasumarthi N, Sherif SA (1998). "Experimental and theoretical performance of a demonstration solar chimney model - Part I: mathematical model development". International Journal of Energy Research 22 (3): 277-288.", see Table I. They break up the overall efficiency into three components: that of the collector, the chimney, and the turbine. They say that the collector has an efficiency of 52-56%; the turbines 77-80%, but the chimney itself only 1.45-3.1%. So the chimney itself is the limiting factor; it has an efficiency that is quite a bit lower than the theoretical maximum given by Carnot's theorem (which is somewhere in the range of 10-15%, depending upon the temperatures you put in). What that shows is that the most important cause of the low efficiency is the thermodynamics: warm air escapes from the top of the chimney before it is put to full use. JdH 16:59, 3 August 2006 (UTC)

Happy with that phrasing. That paper seems not to be referenced yet, and might be the topic I've been most concerned was missing a good reference - can we add it? --Scott Davis ^Talk 14:59, 4 August 2006 (UTC)

Sure, go ahead JdH 16:14, 4 August 2006 (UTC)

• Admitting my ignorance, if capacity is quoted in MW, I think it refers to a maximum rate of generation, not an indication of total electricity generated in a year, or any indication of ability to generate on cloudy days. The efficiency and competition sections appear to be drawing comparisons to systems that seem to only be useful in direct sunshine. There is no comment in this article about effectiveness under cloud, but there is an indication it can continue to generate overnight, without the addition of a gas burner. Does a 500MW generator on 18.2 km² actually generate 2.5 times as much electricity in a year as a 200MW solar updraft tower on 38 km²? If not, the comparison is misleading.

Yes, that is what it says, and it is accurate. Cloud cover I don't know; somebody claimed somewhere that the Solar tower should work under a cloud cover (don't remember where that was), but there was no source to back that up. I question whether it would work all that well under a cloud cover. btw, concentrating solar thermal power plants are designed to store heat as well, to help them get through the night or cloudy periods.

SolarMission claim "The collector can use both direct and diffused solar radiation; this is in contrast to other major large-scale solar-thermal power plants that can only use direct radiation." SBP claim "A single Solar Tower power plant with a collector area of 7 000 m in diameter built and operated in an area with an annual global solar radiation of 2 300 kWh/m² a will generate between 700 and 800 GWh per year" which appears to be an average of about 91 MW sustained generation. I haven't found comparable numbers for other plants. --Scott Davis ^Talk 14:59, 4 August 2006 (UTC)

We need independent and verifiable sources, and SolarMission claims don't qualify as such.
The SBP numbers for the 1km high tower are estimates; we wouldn't know how it really pans out until it is actually built. The only "hard" numbers are those of the Spanish prototype, which are even lower. I am pretty sure the numbers for "annual electricity' generation are somewhere out there; Sandia National laboratory has lots of detailed information on the the stirling/dishes that are planned for California. But I see no reason to think that this is going to make all that much of a difference. Furthermore, I don't think we should get into a discussion of Dispatchable Technologies vs Intermittent Technologies as you are suggesting; that is a pretty complicated issue, and would take a whole article to properly cover it. In the end it is a bottomline issue, and I thought we agreed to stay away from that. JdH 16:14, 4 August 2006 (UTC)

I agree I didn't find reliable sources for annual capacity, and that they are all only estimates and predictions until the thing is actually built. However I think that GWh/year is probably a more interesting measure for comparison than the headline MW number for comparing baseload electricity generation capability. That's why I brought it up. --Scott Davis ^Talk 02:09, 5 August 2006 (UTC)

• "Competition" should be renamed something like "Other commercial-scale solar power stations". That name is too long, but the section is about other solar technology, not about other sources of electricity in the same market, which is what "competition" suggests.

What about "Alternative solar thermal power plants"? JdH 16:59, 3 August 2006 (UTC)

That's better. --Scott Davis ^Talk 14:59, 4 August 2006 (UTC)

Style

• I think it's against guidelines to gratuitously change metre and kilometre to meter and kilometer.
• The formatting near the top diagram is odd.
• ref 14 has year=0000

that's because that paper in in the press, i.e.: not yet published. The year should be put in after it has actually been published. JdH 18:02, 3 August 2006 (UTC)

• There should be wikilinks to the (potential) articles for the specific power plants being used for comparisons (eg English translation of de:Andasol 1).
• "SCE/SES" needs to be expanded/explained/wikilinked on first use.

--Scott Davis ^Talk 15:36, 3 August 2006 (UTC)

There are a few recent edits to the article by Jefflundberg and Rossgk that may be worthwhile to incorporate. JdH

I think we're finally getting somewhere! Thanks. --Scott Davis ^Talk 14:59, 4 August 2006 (UTC)

CP/M: I think this discussion is just about wrapped up. Can we prepare a final version on the basis of this discussion, and post it to the article? JdH 13:19, 22 September 2006 (UTC)

I thought it could be done quite a long time ago. However, now the article has somewhat changed, so probably it would be better to apply a kind of merge between them, fixing the mentioned details. CP/M ^comm |Wikipedia Neutrality Project| 21:05, 22 September 2006 (UTC)