Talk:Photovoltaic system

Merger discussion
Lots of improvements needed, hope there's an engineer out there who can help. Needs a merge with Array Oldboltonian (talk) 00:08, 10 February 2008 (UTC)

A merger discussion has been started regarding the organisation of Photovoltaics, Photovoltaic array, Solar panel, Photovoltaic module, Photovoltaic system and Solar cell. If you would like to contribute to this discussion please click here. GG (talk) 08:23, 25 July 2008 (UTC)

TOU net-metering: offset total cost, or offset total usage?
In California at least, utilities are required to offer time-of-use (TOU) net metering for residential solar systems in order to allow people to run the meter backwards and reduce their electric bill at different rates during on-peak and off-peak times (usually noon to 6PM). Obviously this is great because the sun shines brightest generally during on-peak hours (which is also why people use AC more during those hours). Given this situation, if I am designing a system I need to ask myself whether I just want to zero out my cost, or whether I want to zero out my usage (annual Kwh used). Without TOU metering these would be the same, but with TOU metering they are not. If I turn off loads during on-peak times, all my generation can be used to reverse the meter at a high $/Kwh rate (on-peak rate) thus reducing my bill to zero even though I may still be a net consumer of electricity. The other thing that plays into this decision is the fact that if I were to zero out my total usage, while being careful about on-peak usage, I would end up with a net dollar credit. I have heard that PG&E is not required to pay this in check form, rather is allowed to simply give a credit on account at the end of each "true-up" period (usually every six months). This credit can build and build but you never get paid in actual money. This all leads me to think that when sizing my system I should do it in such a way that I zero out my dollars instead of my Kwhs. Of course the sizing calculations for this will have many more variables to consider, such as my expected on-peak and off-peak usage, the cost differential between on and off-peak Kwh, insolation as a function of time of day, etc. A quick calculation shows that the system size will be about 3/4 of the size it would need to be to offset usage. That's a lot. Any thoughts that might help? Is this a topic that should be elaborated in the main article here? Ric Barline (talk) 21:33, 10 March 2011 (UTC)

Hybrid PV-Thermal Systems
The current article has a section titled "Hybrid Systems" and this refers to systems that include both PV and some form of electrical energy storage or Combined Heat and Power System. But there is another type of system that also is termed "Hybrid", namely PV panels that are designed to produce both electricity and thermal energy in the form of hot working fluid that keeps the panel cool while extracting heat into a tank for other uses. There is significant development going on, especially in Germany (e.g. Solar Zentrum Algau ), and at some point very soon these types of panels will begin to penetrate the U.S. market. My point in bringing this up is that I think someone needs to include a section on this in the main article.Ric Barline (talk) 17:56, 16 March 2011 (UTC)
 * You know what to do! Find a ref, write it up! YouTube videos are not good references, though. Is there some literature you could cite? --Wtshymanski (talk) 14:46, 2 April 2011 (UTC)

Merge proposal
I propose to merge Solar photovoltaic monitoring and Solar performance monitor into this article as monitoring is a part of the photovoltaic system's performance. Beagel (talk) 14:44, 3 August 2011 (UTC)
 * Go for it. They are both little more than ad-talk and could be boiled down to a paragraph or less. --Wtshymanski (talk) 15:30, 3 August 2011 (UTC)
 * I agree with your assessment. However, I am not expert in this field, so maybe you could take a care of merging these articles if there will be consensus for this. Beagel (talk) 19:54, 3 August 2011 (UTC)
 * Agreed --FNQ (talk) 01:07, 4 August 2011 (UTC)


 * Support Suraj  T  10:07, 31 August 2011 (UTC)
 * Done...a while ago. Remember to identify source articles in edit comments for GFDL compatibility, otherwise you'll get stomped. --Wtshymanski (talk) 21:55, 3 April 2012 (UTC)

Insolation Factors and energy output
Moved from User talk:Wtshymanski

Regarding [this] edit. I have to disagree with your revert logic as a wide range of energy production was covered in the article and could easily include Alaska and all artic circle inhabited areas as well as the specific countries geographies previous listed. Also the annual production was not mentioned although the daily figure should include and average of anual production or state complex details (yuk). Either way I have removed the statement from the section because it is off topic for the section and covered quite well in the "Insolation and energy" section above using a 150W panel example making the text, in question, repetitive information. If you want to re-add text of this nature please discuss this on the talk page first. Thank you 174.118.142.187 (talk) 04:40, 23 October 2012 (UTC)


 * 174.118.142.187, your version is not supported by the sources. The reference specifies that these are the numbers for Australia. Because the reference specifies that the numbers are based upon "The number of daylight hours (governed by where you live)" and "The intensity of the sunlight (governed by where you live)", it is reasonable to list areas that are within the range of latitudes of Australia in ether hemisphere. You cannot use a reference that specifies Australia for "most climates", and thus I have reverted your edit.


 * Your claim that the 3.5-5 kWh figure applies to the arctic circle makes me question whether you have the technical knowledge needed to correct other editors in this area. At the Arctic circle, the minimum daily output is zero kWh, not 3.5 kWh. --Guy Macon (talk) 07:15, 23 October 2012 (UTC)

Moved by 174.118.142.187 (talk) 14:15, 23 October 2012 (UTC)


 * What sources were you referring to? It was removed with the statement. Please do not use an insulting tone. The statement was removed because it was repetitious information, in the wrong section of the article, area specific and the range originally specified could cover almost any area in the world, including inhabited areas of the arctic circle, as stated in my edit history comment. See arctic area insolation information [here]. Your comment "At the Arctic circle, the minimum daily output is zero kWh, not 3.5 kWh." refers to a minimum figures but the article statement does not specify the arithmetic used. It was assumed it was a annual average per day. Perhaps that is the discrepancy? Either way, this statement belongs in the "Insolation and energy" section and not where it currently lives in. I will move it there for to a more appropriate section, where energy is being discussed with various geographical examples. 174.118.142.187 (talk) 14:15, 23 October 2012 (UTC)


 * Please WP:AGF. I have no opinion regarding whether it should be moved or any of the other side issues you have raised. I am merely pointing out that your statement above ("Regarding [Wtshymanski‎'s] edit. I have to disagree with your revert logic as a wide range of energy production was covered in the article and could easily include Alaska and all artic[sic] circle inhabited areas as well as the specific countries geographies previous listed.") is wrong. Wtshymanski‎'s revert logic was correct, and the version you reverted to is not supported by the source that is cited with the statement. If some other cite supports your version, you should have cited that rather than inserting a statement that is not supported by the citation attached to it. --Guy Macon (talk) 19:04, 23 October 2012 (UTC)


 * LOL The discussion and edits have become confused, apparently. I removed the statements and the reference and you reverted my edit, installing it again. Then you appear to be stating the references do not support my statement?? The arctic circle comment, by myself, was exagerated unitentionally, as I was assuming it was north of 60 degrees, not 66 and Alaska is a bit south of that yet. Many installations in Alaska have very productive PV systems installed and they do fit the stated range but... I see some confusion as it seems the article statement was implying a daily min and max production for each month of the year, not a daily average of the years production. Alaska certainly doesn't meet the article definition (3.5-5 kWh/day) due to it's winter months. Forgetting any confusion on either part, nice catch and thanks for making me aware. 174.118.142.187 (talk) 20:47, 23 October 2012 (UTC)

Blocking Diodes?
This myth stated with people thinking the bypass diodes on PV panels were blocking (series) diodes. The PV panel itself is dozens or even hundreds of diodes already in series to manufacture it. Another diode does nothing, isnot needed, never used and never recomended by PV panel manufacturers. Now we have diagrams showing usage of a bocking diode and text supporting this. This all has to go unless somebody can demonstrate some references to manfacturers recommending the usage of this. I have removed this erroneous information. Do not eplace it without appropriate references. 174.118.142.187 (talk) 13:32, 5 November 2012 (UTC)
 * I have no reference at the moment, but I believe the requirement for blocking diodes (or not) depends on the PV cell technology, and the use to which they're put. From memory, monocrystalline cells in series and/or parallel require no external diodes as their own reverse leakage current is tiny, but this is not true of the cheaper polycrystalline ones, and even less so for amorphous cells. Having said that, it only matters if the cells or modules are connected straight to storage batteries, as the batteries can discharge through the cells overnight. If PV modules are connected to an inverter, there is no problem, as the grid will not leak through the inverter however dark it is! Maybe these two points should be confirmed via refs, and then added to the article somewhere. --Nigelj (talk) 20:59, 22 January 2013 (UTC)
 * Solar modules are comprised of a diode for each 0.5 volt output. The accumulated PiV for a module is huge and varies with the number of cells in series. This manufacturers website has instalation specs for IEC and UL rating systems at no more thn 1000 and 600V respectively. Trouble is the charts require some interpolation by tech people to determine. Fusing is recommended in series with each string of PV panels but not diodes. Added diodes would not pass NEC or CEC requirements. If a whole string shorted the fuse would simply open circuit. In a low voltage system a series diode can cause a sysem to loss as much as about 40-70% of the power. This ma be hard to understand at first but consider a 12 V system with an open circuit PV voltage of 15-16 volts and a charged battery at about 14.5 V or higher in the cold weather. Now knock out a 1 V drop for a diode. Charge drops to next to nothing. Many hobbyists are using 600V worth of series panels and letting the MPPT chop/regulate to 48Vdc. No diodes are neede as the panels are rated for it. Now to provide simple references?? Spec. sheets work for me but some think reading them is "original research". The rest is just hearsay using installers and sales people, usually. 174.118.142.187 (talk) 02:37, 26 January 2013 (UTC)

Blocking diodes are needed to keep full-sun parts of a multi-cell module from melting adjacent cells which may be partially shaded. Here is a good explanation (pages 18 and following): http://www.egr.unlv.edu/~eebag/Photovoltaic%20Devices%20III.pdf Megapod (talk) 12:37, 27 June 2013 (UTC)

File:SolarCell-IVgraph3-E.PNG is a copyvio
I marked this file as a copyright violation, as I found the identical image in the cited ref, on its page 15, marked "Copyright © Siemens Energy & Automation 2009 - All rights reserved". I suggest making a modified version of File:I-V Curve T.png showing representations of Vopt, Iopt and Pmax on at least one of the curves. A good first step would be to convert that image to SVG, getting rid of the step-wise pixelation in the current version, then produce the other version from that. All this is beyond my graphics ability versus time limitations at the moment, I'm afraid. --Nigelj (talk) 21:07, 22 January 2013 (UTC)

Efficiency Numbers
Hi, just wondering about efficiency numbers. Under "Insolation and energy" there are some numbers without sources, then there is a heading "Module efficiency" later with slightly different sourced numbers. Just wondering if the earlier should be removed, changed or linked to below. I see why it is required in the earlier paragraph to calculate the expected energy per area, perhaps then the "module efficiency" heading needs to go first? Marc — Preceding unsigned comment added by 209.53.110.141 (talk) 22:56, 21 June 2013 (UTC)


 * The march of science results in ever-increasing efficiency numbers. Some older numbers persist all over the web. All efficiency quotes may be ignored, as they will be surpassed. Latest, highest, claim seems to be 34.9% . As a practical matter, efficiency is immaterial, since the "fuel" is free anyway, and you can use more panels of lower efficiency or fewer panels of higher efficiency to achieve the same results, as measured in watt-hours per day. It's a question of economics, the principal constraint being available mounting rack space (whether roof or ground). My suggestion is to delete all exact PV efficiency numbers from all PV articles, and to just give a vague numeric range, such as 15% and up. Megapod (talk) 18:35, 27 July 2013 (UTC)


 * The new claim for efficiency is 44.7%. This was achieved in part by building a four layered solar cell, where each layer harvested a different range of light waves, in an attempt to catch them all. It will be a while before panels of this type are readily available to the public. Megapod (talk) 15:52, 12 November 2013 (UTC)

No OK
To behave like that is not ok. -- Rfassbind (talk) 16:12, 3 November 2014 (UTC)

Batteries table
The content doesn't seem particularly pertinent to PV systems, it's a general table comparing some different types of batteries and energy storage systems. Unless the content is somehow keyed to some authoritative ranking of suitability to the use in a PV system, perhaps it's excessively specific. For instance, how does the claim in the table title text "Lithium-ion batteries offer high voltages and storage densities" affect their use in PV systems? I don't think the table adds value for the reader and we'd be better off describing what matters for choosing a battery for a PV system instead of firing a bunch of parameter ranges at the reader and expecting her to figure out if "cycle life" is more important than "power density" in PV systems. Dumb lists of numbers we can get from Google - what we need is an encyclopediac overview of what numbers are important in this context. --Wtshymanski (talk) 16:15, 3 November 2014 (UTC)

Image needs replacing or editing
The image https://en.wikipedia.org/wiki/Photovoltaic_system#mediaviewer/File:PV-system-schematics-residential-Eng.png in the grid connection section is bad, and should be removed, replaced or edited to make it at least somewhat accurate.

The diagram shows the storage battery connected directly to the AC wiring, this is not typical or feasible. It either has to have a charger and inverter combination in between or it could be connected to the DC side of the included inverter if it is only charged from the solar supply. Certainly some consumer controllers may include the functions inside a box but it is incorrect to connect the DC battery to the AC side if there has been an effort to indicate an inverter from the solar to mains conversion. It is also wasted energy to charge the battery with solar power after it has been through an inverter first, rather use a standard charging regulator to minimise losses.

Idyllic press (talk) 09:54, 3 March 2015 (UTC)


 * Correct, the battery should be connected to the DC, rather than the AC side. You could ask the author to amend the diagram. In case the author is not available or I don't hear from you in the next few week, I might consider to convert the diagram to a SVG format and modify the schematic myself. Cheers, --  R fassbind  -talk   02:14, 20 March 2015 (UTC)

95% of what?
"produces about 95 percent of net clean renewable energy over a 30-year service lifetime" This sentence occurs in the lead paragraphs. 95% of what? What are the numerator and denominator in this "95 percent"? — Preceding unsigned comment added by 156.77.111.16 (talk) 16:09, 22 July 2016 (UTC)

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Dated
Much of the prices have changed since 2013.

John W. Nicholson (talk) 05:20, 17 February 2018 (UTC)

Hong Kong and China
A user reverted my edits again and again. I've deleted the photo in question, because Hong Kong is not China. I've shown him a more appropriate article for that photo, but he wouldn't listen.

The article is Energy in Hong Kong.129.127.32.138 (talk) 06:16, 23 December 2019 (UTC)


 * I am listening. I just disagreed. There is a difference. Hong Kong may be administered differently, but it is part of the same nation. I linked Wikipedia policy to you a few times, specifically WP:BRD. There is a related discussion at Talk:Solar power in China for interested editors. MartinezMD (talk) 06:33, 23 December 2019 (UTC)


 * That discussion is also by me. I started the discussion here and there after you told me to.129.127.32.138 (talk) 06:42, 23 December 2019 (UTC)


 * On this section, all the other images used are labelled as city name, then country, eg Helsinki, Finland; Boston, United States; etc. I will revert here per my disagreement WP:BRD. I would add no one else has objected. So seek consensus with other editors' involvement. MartinezMD (talk) 17:34, 23 December 2019 (UTC)

Wiki Education assignment: Research Process and Methodology - FA22 - Sect 201 - Thu
— Assignment last updated by SheilaSh11 (talk) 17:18, 26 November 2022 (UTC)

Delete table in costs section?
I suspect we should delete it because it assumes 10% capital cost but I thought in reality that would vary a lot by country Chidgk1 (talk) 18:25, 15 April 2024 (UTC)