Talk:Growth of photovoltaics

Misnamed

This article is not about the history of PV. It appears to be about PV system deployment. I propose renaming it to Photovoltaic system deployment. Jojalozzo 12:16, 7 July 2010 (UTC)

I agree. I was thinking this is a list. Anyway this is more about power generation capacity from solar cell technologies. Photovoltaics is a term used for study and not production. Photovoltaic is a redirect to Photovoltaic array which I find overly restrictive and imprecise for this list. So maybe something more like List of semiconductor based solar power generation capacities. No, I'm not happy with that name, but a change is needed. Vegaswikian (talk) 22:22, 15 July 2010 (UTC)

Growth Rate Wrong?

The chart of new PV production shows 77,000 MW projected capacity production in 2016, and 50,655 MW estimated capacity production in 2015, but describes this as 34% growth in new capacity (clearly not in capacity, as 0% growth rates are shown). But that's 52% growth in added capacity. — Preceding unsigned comment added by 96.95.24.246 (talk) 18:22, 7 February 2017 (UTC)

You are right. I'll change it. --Ita140188 (talk) 02:40, 8 February 2017 (UTC)

Changing page title and scope

I would say, something like: Photovoltaics_solar_power as per Concentrated_solar_power. And anyway displaying every year's results is too cumbersome. What would be if every subject, like List_of_countries_by_population kept every year's list ? --Robertiki (talk) 19:09, 15 April 2014 (UTC)

And to be merged with Photovoltaic power station --Robertiki (talk) 19:12, 15 April 2014 (UTC)

Chart caption

I suggest putting the caption of the chart below the chart and not as currently above, like the other images/pictures in the article are designed/layouted. Sadly I do not understand the template that is used here to do it myself. 78.35.203.136 (talk) 07:21, 20 June 2014 (UTC)

global electricity demand

"By the end of 2014, cumulative photovoltaic capacity reached at least 177 gigawatts (GW), sufficient to supply 1 percent of global electricity demands"

I think that this paragraph is wrong, it has no citations, how is it calculated?

the world factbook says https://www.cia.gov/library/publications/the-world-factbook/geos/xx.html

Electricity - production: 22.03 trillion kWh (2011 est.) that is 22.03 trillion kWh / year = 2500 gigawatts

Electricity - consumption: 20.45 trillion kWh (2010 est.) that is 20.45 trillion kWh / year = 2300 gigawatts

http://en.wikipedia.org/wiki/Electric_energy_consumption (cites world factbook. 20,279,640 GWh / year = 2300 gigawatts) https://en.wikipedia.org/wiki/List_of_countries_by_electricity_consumption (cites world factbook again 19,320,360,620 MWh / year = 2200 gigawatts)

According to this http://www.eia.gov/cfapps/ipdbproject/IEDIndex3.cfm?tid=2&pid=2&aid=12 Total Electricity Net Generation (Billion Kilowatthours): 21,531.709 in 2012 = 2500 gigawatts

177 gigawatts / 2500 gigawatts = 7%, not 1%

So now I am confused. The world consumption data is from 2010, 2011, 2012 did it grow so much in 2014? did I calculate something wrong?

This other paragraph has at least a citation: the eia Technology Roadmap: Solar Photovoltaic Energy 2014 edition

"By 2050, solar power is anticipated to become the world's largest source of electricity, with solar photovoltaics and concentrated solar thermal contributing 16 and 11 percent, respectively. This will require PV capacity to grow to 4,600 GW, of which more than half is forecasted to be deployed in China and India.[7]"

Can it be true? it predicts an electricity usage of 4,600GW * 100/16 = 28,750 gigawatts in 2050 if I understand it correctly. More than 10 times current electricity usage. — Preceding unsigned comment added by Argento (talk • contribs) 16:54, 5 April 2015 (UTC)

This paragraph "By the end of 2014, cumulative photovoltaic capacity increased by 38,700 MW and reached at least 177 GW, sufficient to supply 1 percent of the world's total electricity consumption of currently 18,400 TWh.[6]" has the same problem 18,400 TWh / year = 2100 gigawatts

177 gigawatts / 2100 gigawatts = 8%, not 1%, so unless I am doing something wrong, these percentages are wrong. — Preceding unsigned comment added by Argento (talk • contribs) 17:08, 5 April 2015 (UTC)

The only possible explanation is that the article is talking about nominal power (gigawatt-peak). In this case I think that every reference should be changed to watt-peak or this is confusing. A gigawatt-peak produces (depending on where the panels are installed) 1000 gigawatthour /year = 0.11 gigawatt, so the calculations will be right. — Preceding unsigned comment added by 79.35.187.239 (talk) 09:20, 6 April 2015 (UTC)

Thank you for your feedback. Here's a quick reply:

• The figures you mentioned are all sourced from IEA-PVPS snapshot report, p.6. I added the page-number to the citation in order to make it easier to find the figure (here). By the way, your comment "This other paragraph has at least a citation" is inappropriate. All figures above are fully cited. You can't expect the lead section to have a citation behind each and every figure, especially when they are repeated in more detail in the body of the article. Also see WP:LEAD.
• You cannot calculate annual power generation directly from capacity figures. Full load hours and capacity factors have to be taken into account. That's the reason why you get 7% instead of 1%.
• Yes, the article uses watt-peak, the nominal nameplate capacity for solar PV and it says so in the beginning of the first section. However, power generation always needs FLH/CF to be taken into account, irrespective of whether it's solar, wind, coal, or nuclear. It is not reasonable to change every unit from watt to watt-peak. Sometimes it makes sense to label capacities with W_p (as the article does in several places) in order to differentiate from W_AC.
• The article uses figures from the International Energy Agency (consumption of 18,400 TWh as per – Key World Energy Statistics 2013). Other sources as the domestic data you mentioned may somewhat differ.
• Hope that helps. Feel free to ask again and try to be a bit more focused in your posts and sign it with four tildes (i.e. ~~~~)

Cheers, Rfassbind -talk 16:18, 22 April 2015 (UTC)

Looks like there is some confusion between production capacity, measured in TW or 1000s of GW, and production, measured in TWh or 1000s of GWh. 1 TW capacity could generate 8,760 TWh in a year! (Although with photovoltaics, probably about 1/3 that much.) 96.95.24.246 (talk) 18:55, 7 February 2017 (UTC)

Pollution aspects

Pollution aspects

In the manufacturing process of photovoltaic cells, Silicon tetrachloride is produced as waste by product when not reused. Silicon tetrachloride can acidify the soil or water when dumped as waste material . Cadmium metal used in some PV cells (CdTe), can cause heavy metal pollution if the disposed PV cells are not recycled. PV cells manufacturing involves substantial amount of water consumption and also moderate regular requirement of water during their life cycle use for cleaning the dust deposits on the panels.

The section above [edited] was added by me explaining the pollution aspects of PV cells. The section was deleted by User:Rfassbind on 6 May 2016 saying the page is not appropriate for the pollution caused by the PV cells. It is totally inappropriate and not neutral view on solar power by concealing the pollution aspects of PV cells. The pollution generated in PV cells manufacture becomes part of pollution in solar power generation when PV cells are used. For information to the readers. 49.207.221.221 (talk) 15:38, 9 May 2015 (UTC)

I have already suggested some alternative articles (see edit comment). In addition, check out Solar power#Environmental impacts, which I forgot to mention. But I have to warn you, the article in IEEE Spectrum refers to an outdated washingtonpost article from 2008. Make sure the information you want to add is sourced to more recent events or studies. -- Rfassbind -talk 16:16, 9 May 2015 (UTC)

You need to explain first why is this article not appropriate place for indicating pollution aspects of PV cells. The cited reference is from reputed IEEE (engineering publication) published in August 2014. If the pollution aspects are no more valid, give the necessary full information with refs. here and close the topic. Being an ardent editor of Wiki articles, are you warning general readers or content enriching people without any returns. 49.207.221.221 (talk) 16:38, 9 May 2015 (UTC)

Unfortunately, accusations of me being this and that is not very helpful. The reason for the removal of section "Pollution aspects" is because of its unsuitable topic for the article. It is WP:Out of scope. The article Growth of photovoltaics specifically deals with the history, current status and future expectations of worldwide deployment of photovoltaics, with a focus on installed capacity and economic aspects. In other words, just because the article's title contains the word "photovoltaics" is nowhere near good enough to add anything related to it. Moreover, if the tone in this thread does not change, I will refrain from the conversation for good. -- Rfassbind -talk 20:25, 10 May 2015 (UTC)

Thank you for changing your tone of conversation with wiki readers and content contributors. I would be happy that the content deleted by you be added in appropriate wiki page by you (being regular editor of many pages on solar energy) as the the content is no way falsifying PV application (vis a vis to other type of electricity generation) widely but bringing out the pollution causing aspects in a subtle way. There is already lot of content which is WP:Out of scope to your scope definition. No body adds content without conviction to what he is writing. Instead of unilaterally deleting the content, express your desire to delete others content in the talk page, give 10 days (say) time for response and if proper response is not coming then delete/modify others content as you like.49.207.221.221 (talk) 21:23, 10 May 2015 (UTC)

Predictions for 2020 all wrong

Extrapolating from the table in section 5.2 "Worlwide cumulative" by 2020 there should about 1200 GW cumulative global installed capacity since there is an approximate doubling of the cumulative total every two years. Even pessimistically allowing only 1.7 times rather than double it would go from 178 GW in 2014, to 302 GW in 2016, then 514 in 2018, and 874 GW in 2020.

So all the forecasts in section 2.2 "Global short-term forecast (2020)" are way too low, the highest being 696 GW cumulative. 88.203.88.246 (talk) 17:49, 7 December 2015 (UTC)

Agree totally. The growth rate is exponential not linear as anybody can see from the "Worldwide growth of photovoltaics" chart at the top of the Article. Even at the pessimistic 1.7 exponential factor you mention then 874 GW will be installed by 2020 and 21,200 GW by 2032 which is 100% of world electricity requirement. Therefore also contradicting the statement in the intro that "By 2050, solar power is anticipated to become the world's largest source of electricity". That is completely wrong because solar will power the whole world entirely by 2032 according to the data in the "Worldwide growth of photovoltaics" chart if extrapolated correctly with the 1.7 exponential factor. Please stop misleading the public, Wikipedia, as you have been doing here for years. I pointed this out ages ago but nothing changes. 141.8.114.29 (talk) 16:03, 6 March 2017 (UTC)

How do you know that these projections for 2020 are all wrong? What makes you think that a linear extrapolation from currently installed capacity and growth rate is correct? Personally, I am also more optimistic than most of the 2020-forecasts listed in the table, but that doesn't mean anything. My opinion is a worthless as yours as long as you can't back up your claim with a reliable source (i.e. a 2020-projection by a reputable organization/company). I think you should read this guideline. In addition, there are some clear statements (e.g. the second paragraph of the lead section) about the quality of growth-projections, especially those made by the IEA... just follow the adjunct citations (currently number 6, 7 and 8); it worth a read... Rfassbind – talk 22:51, 8 December 2015 (UTC)

The "reliable source" you require is simply the "Worldwide growth of photovoltaics" chart at the top of the Article. Just look at the data and you can see the installed GW are increasing by 1.7 times or more every two years. It is quite obvious. Then just do a few multiplications by 1.7 and you get 874 GW by 2020 and around 21,200 GW by 2032 namely the entire world's electricity requirement. 141.8.114.29 (talk) 16:14, 6 March 2017 (UTC)

Without pushing a POV I am quite comfortable affirming that IEA projections are voluntarily wrong. They are mainly paid by oil companies and OPEC states so they do not want to affirm facts potentially pushing the price of oil down. Silvio1973 (talk) 11:49, 11 April 2016 (UTC)

This may be interesting: http://www.vox.com/2015/10/12/9510879/iea-underestimate-renewables --Ita140188 (talk) 06:45, 18 October 2016 (UTC)

Exponential growth does not continue for long, usually. It's all about guessing when it is going to slow down. There's no reason to believe that this rate of growth is going to be sustained until 2020, and surely it seems unreasonable to imagine it going on until 2030. --Ita140188 (talk) 10:00, 7 March 2017 (UTC)

This discussion is hilarious. You can't know objectively what it will look like. For me the best prediction is the exponential one. You may mention the underestimating article alongside with their ludicrous linear predictions. 89.103.252.191 (talk) 14:22, 22 March 2017 (UTC)

As you can see from Solar power in Germany or Solar power in Italy, growth rate are exponential up to a point, then they slow down dignificantly, resembling a Logistic function. In both countries, this happened when the share of electricity by PV reached around 7-8% of total electricity consumption. Of course these are only two examples, but if had to guess for the world capacity growth, I would think of something similar, surely not exponential at the same rate up to 100% of electricity consumption. This would make no sense whatsoever for so many reasons. --Ita140188 (talk) 05:25, 12 April 2017 (UTC)

Update needed

Hi, the whole page needs an update. There are updated data for 2015, see e.g. https://www.greentechmedia.com/articles/read/gtm-research-global-solar-pv-installations-grew-34-in-2015 Also I would remove a lot of not very useful information, for example previous and outdated previsions are useless IMO. The table "IEA – projected annual PV installations" comparing different previsions between 2013 and 2014 is also useless. The article should just talk about past data (removing all past previsions) and possibly previsions for future data.

There need to be a decision on what to do with past projections. I think it would be interesting to have an overview of how PV was expected to grow in the past compared to how it turned out to be. But surely it needs to be rewritten and it seems like a lot of work. --Ita140188 (talk) 09:30, 1 November 2016 (UTC)

Concur that an update & re-write are long overdue. 71.175.173.113 (talk) 05:39, 8 January 2017 (UTC)

Before April 2017, there probably won't be a "Snapshot of Global Photovoltaic Markets 2016". Until then, a significant update can't be done without losing consistency. In the meantime, I'll be revising the article's historic data, moving past projections (previous forecast) and annual deployment figures by country to History of photovoltaic growth. Constructive suggestions posted in this thread during my multi-edit revision are appreciated, Rfassbind – talk 14:05, 7 March 2017 (UTC)

2014 numbers are all throughout this article, often saying current but not dated. In a field changing as rapidly as this any number needs to have an associated date. Maybe we need to use "As of" again. Rmhermen (talk) 19:10, 27 October 2018 (UTC)

Forecast

There is not a single current prediction in this entire section. None of it is useful to the reader. All of it either predicts things at already past dates or has been superseded by other, likely, just as inaccurate predictions. No such section should probably exist as it requires a great deal of work to keep updated (which it has evidently not been) and solar predictions are infamously inaccurate. Rmhermen (talk) 04:18, 19 October 2018 (UTC)

I concur. This section is quite out of date and most of its content is not worth keeping. It would be great if it could be overhauled with a long-term global focus, but the past and regional forecasts are not necessary here. My suggestion would be to move the GTM forecast (through 2022) and a summary of the long-term section to a new subsection of History of Market Development. Reywas92^Talk 04:59, 19 October 2018 (UTC)

I don't disagree that a lot of information in the section is a bit old. Maybe it could be condensed and updated with newer information? I don't believe that "forecast for 2017" section should be there. Most of that information should be covered in a short term report. I do believe that there should still be a short term and long term predictions sections. Short-term meaning maybe 2018-2030 and long-term meaning present to 2050. The current long term section could definitely use some condensing and updating. I'm not too sure about that regions section. I would imagine that a long term forecast report would already mention some things about the regions with highest projected growth. I think that it's important to have some projections from reputable sources seeing as the whole article is about the growth of photovoltaics.--SeminoleNation (talk) 05:03, 19 October 2018 (UTC)

The awful track records of forecasts is perhaps the most significant thing to report. See [1] for instance. The IEA was ridiculed for the predictions and released a second set in 2017 with "new" methodology and even in its first year only continued to miss (73GW instead of actual expected 103MW). The U.S. agency a few year ago released a ten-year forecast that was lower than the actual completed in the very next year (meaning projects already under construction when the report was released exceeded their 10-year total estimate) GTM is slightly more realistic but updates their current year forecast multiple times throughout the year - which is not a good way to create a stable article. We don't have people who will update that consistently. Rmhermen (talk) 18:03, 27 October 2018 (UTC)

Given the IEA's track record, why is it the only projection cited in the intro? Even PV industry association projections are remarkably conservative, forecasting PV to "more than double over the next five years" when it's more than quintupled every five year period since 1990. The IEA forecast of 4.7 terawatts by 2050 is absurd. Prices continue to fall, so 4.7 TW is more likely by 2026 than anytime after. EllenCT (talk) 06:51, 21 November 2019 (UTC)

PV deployment growth has slowed down significantly in recent years, and is approaching a steady growth (as opposed to exponential). And the more it is deployed, the more it is difficult to deploy more (due to increasing grid integration costs, such as storage and transmission infrastructure). Of course prices are falling too, but assuming it will grow as it did in the past is not obvious. In the near future in saturated markets the dominant costs will be grid integration, not the solar panels themselves. It will need much support from countries and that is mainly a political question. Also keep in mind that while the IEA forecast has been terrible at predicting PV deployments, solar still plays a very minor role in the world energy system (even when considering electricity only it is around 2%), so its deployment is more volatile. --Ita140188 (talk) 03:40, 22 November 2019 (UTC)

@Ita140188: what is your source for approaching steady growth? I keep seeing tenders under $0.02/kWh and I'm not seeing them slow down. EllenCT (talk) 03:36, 25 November 2019 (UTC)

If you plot the cumulative growth %, the trend is quite clear. It is going down. That doesn't mean that annual deployments are decreasing, they are in fact increasing. But they are not increasing exponentially, and if this trend continues, at some point they will increase constantly. Of course this is the only sustainable outcome in the long term, since exponential growth cannot go on forever. The point is it is difficult to predict at what solar % we will have stabilized. Also note that in the long term a constant deployment means a constant installed capacity, since the lifetime of panels is not infinite (all Wiki articles assume that "cumulative installation"="current installed capacity", which is true only in early stages of deployment or with exponential growth). --Ita140188 (talk) 03:45, 25 November 2019 (UTC)

What is your source for those assertions? [2] Shows a one-year stall flat in 2018, under tariffs, in contrast to an actual decline in year-over-year figures in 2013. Would you have made the same prediction then? Do you believe year-over-year variability is more predictive than the r² of 0.95 for an exponential fit? EllenCT (talk) 04:17, 25 November 2019 (UTC)

@EllenCT: Also, I am not sure what you mean with your reference to prices. Prices and deployment are not the same. Also, as I mentioned before, for saturated markets (such as California or Germany) we are approaching the point where the grid integration costs are higher than the panel costs. Even if your panels cost zero, they are useless if they produce energy only when all others are also producing and nobody needs additional energy (value is zero). At that point, your true cost of energy becomes the cost of storage, not the cost of the panels. --Ita140188 (talk) 03:49, 25 November 2019 (UTC)

@Ita140188: Again, what are your sources for the saturation assertion? I see just the opposite: "Experience from Germany, Spain and Scandinavia shows that low-cost integration is possible, while the continued growth in operating experience, development of new markets for flexibility and emerging innovations are constantly reducing the expected costs and difficulty of integrating ever higher shares of VRE in the system."[3] If the 1,700 gas plants in North America are all producing at about $0.04/kWh it still makes sense to replace them with PV at $0.018 or lower even when all the demand is met. Do you think power company CEOs are going to forgo that opportunity to earn greater bonuses pegged to their financial performance? EllenCT (talk) 04:34, 25 November 2019 (UTC)

@EllenCT: Article talk pages are not forums, so we should maybe move this discussion to our talk page. Anyway, for my first comment, cumulative growth was constantly over 40% before 2012, and constantly below 40% after. For this year, it will be around 25%. It seems a declining trend to me. An exponential growth would need a constant % increase. Of course when you plot very long time series, such as in the figure, it is difficult to see the recent trend.

The exponential model will fit particularly well because it gives same weight to values from the 1990s as to values from today, even though we have several orders of magnitude more deployments today. As for the saturation assertion, it is well known in the literature. There are so many references that I am not sure what to reference here. To be short, as long as you have a lot of dispatchable generation and backup, as in the case of coal in Germany, you are ok. But if you want to shift to high penetration solar without subsidizing idle coal capacity, then it's just logic: you need a lot more storage and a lot more transmission capacity (as compared to a coal based power system for example). To be clear: I would be super happy if I'm wrong and solar grows to 100% in 2030. --Ita140188 (talk) 04:37, 25 November 2019 (UTC)

Perhaps it would be an improvement to the article to explain that the natural market progression to take the highest cost plants offline when solar is added leaves the more easily dispatchable second best cost gas plants remaining, thus solving the load shaping issues without storage. I stand by my assertion that leaving the IEA as the only projection in the intro without specific counterpoint is an affront to accuracy and degrades the quality of the article. EllenCT (talk) 04:42, 25 November 2019 (UTC)

For this to work, you still need gas plants and you would still produce a lot of CO2. Also, you need a lot of peaker gas plants, which are the most expensive ones. The whole system would be a very inefficient use of capital, since you would have very low capacity factors for most of your dispatchable plants (either gas or storage). Either way, I am not saying it's impossible to integrate, but the more the penetration, the more these costs cannot be ignored. There is a point where these costs exceeds generation costs. By the way, nowadays it's not only IEA that forecasts stable deployments, it's also Greentech Media (Wood Mackenzie) which are quite enthusiastic about solar: [4]. --Ita140188 (talk) 04:50, 25 November 2019 (UTC)

Here are a bunch of peer reviewed papers claiming 100% renewables is achievable in every market. I'm happy to read the countering evidence if you point me to it. EllenCT (talk) 07:11, 25 November 2019 (UTC)

@EllenCT: I know the literature well. I also know some of these authors personally. I never said it's impossible, I said it would probably very expensive and it is definitely very unlikely to happen. Also, not all literature has the same quality. In particular, some papers by Mark Z. Jacobson have very serious flaws in my opinion, see [5]. All these papers are heavily reliant on assumptions which are difficult to evaluate clearly. --Ita140188 (talk) 07:30, 25 November 2019 (UTC)

@Ita140188: I will give you my reaction to the first of the 19 points raised in that document, and then ask you a question. As for, "nuclear power produces over 60% of total US low-carbon electricity today, but in Jacobson et al. they are omitted entirely from consideration." My understanding is that the issue is one of cost, such that if you shut down a ~$0.15/kWh plant under a tariff which allows charging customers $0.25, replacing them with $0.05 renewables, that gives you $0.10/kWh extra revenue without which you would not be able to replace your fossil plants with renewables as quickly. Now, which of the 19 points do you personally find the most persuasive? EllenCT (talk) 08:13, 25 November 2019 (UTC)

All points are important. I think the most glaring absurdity in Jacobson's assumptions is that hydropower can provide 1300 GW of power, which is over 15 times the currently installed hydropower capacity in the US. This while accounting for exactly zero capacity expansion of hydropower. All the other points are also important, but this alone shows you how flawed some of these studies are and how their conclusions have limited value if any. As for your repeated point about lowest cost generation, this is actually a bad point about renewables. Of course they enter the market at zero marginal cost, so when there are too many of them they depress the value of electricity at that time until the value of generation (also for themselves) is zero. Renewables are profitable as long as there are expensive dispatchable generators that increase the marginal cost of generation in the electricity market. --Ita140188 (talk) 09:44, 25 November 2019 (UTC)

Inconsistencies in table

The two cited sources in the main table, IRENA and IEA-PVPS give very different numbers for many countries. I suspect it may be due to IRENA only considering utility scale installations (but I may be wrong). For example for the United States in 2020, IRENA gives 75 GW (in the table now), while IEA gives 93 GW ([6]). Same for many other large countries such as Japan, Germany, and India. We should use only one reference for the table to avoid inconsistencies. For example, for the United States it appears that 53,184 MW were operational in 2018, 13,300 MW were installed in 2019, and the total for 2019 is... 60,682 MW, and not ~66 GW as it should. I suggest to use IEA data (which appears to be more comprehensive) when available, and use IRENA only for countries for which IEA data is not available. --Ita140188 (talk) 02:55, 27 May 2021 (UTC)

EU data

I tried adding EU data for 2021, but as noted below, the data vastly differ between the two sources. Where are the 5-digits numbers coming from? Also, how is "EU" handled with regards to countries joining/leaving the block?