Talk:Solar energy

Application of concentrated solar power (e.g. with a parabolic mirror) for to drive a sterling engine

Concentrated solar power (e.g. with a parabolic mirror) for to drive a Sterling engine should be mentioned as an application somewhere in the article, maybe as an extra point after " ... ventilation ...". A good and short (21 sec) video that shows an example of such a system is seen here: http://de.youtube.com/watch?v=nq6iCO9KLKA&feature=related --77.184.142.94 (talk) 12:53, 16 January 2009 (UTC)

I think we used to have a photo of one in the article. 199.125.109.37 (talk) 14:31, 23 January 2009 (UTC)

Move navblocks to proper location

{{editsemiprotected}} Please move the three navblocks

• {{Solar energy}}
• {{Renewable energy by country}}
• {{Electricity generation|state=autocollapse}}

to their proper location at the end of the article, just before the list of categories. 199.125.109.37 (talk) 20:20, 18 January 2009 (UTC)

 Done By the way, when you complete the request, you mind putting tlx in front of the template? Thanks Leujohn ^(talk) 10:59, 19 January 2009 (UTC)

Disadvantages of some pictures, examples, explanations about greenhouse effect in buildings in regions with a winter period

There are some examples of using greenhouse effect in buildings. In principle very good to mention it, because more than 50%, even more than 80% of all energy (for lightning, warming and cooling) used in buildings is wasting energy - until today - because greenhouse effects are not calculated in the architecture as it could be.

But for this aim, using this chance, it is nearly always bad to have glas, resp. windows at the roof, namely because this causes too much heat in the summer, and in winter it is also not the best way, because then the sun is much more near to the horizon, so windows on the roof normally do not let in the light in an optimal way. (Exceptions are some kins of real greenhouses for plants, or buildings in cold regions (e.g. on high mountains) near the equator).

In regions where there is a winter periode, the most effective way for using greenhouse effect is a highly glassed front on the equator side (north hemisphere: on the south side; south hemisphere vice versa) and highly insolating materials, with nearly no windows, on all other sides of the building, including the roof! Additional it is very effective to have highly insolating jalousins (venetian blinds) for the nights (except in summer, when they may be used partly at noon for to give shaddow - another way for shaddow in hot days are plants, which can be positionend in some ways in front to the windows in summer). --77.184.138.252 (talk) 13:58, 19 January 2009 (UTC)

Look for a photo of a "zero-energy building"? Apteva (talk) 02:10, 27 January 2009 (UTC)

Recent edits to the lead

The new User:Amspock is welcome to this page. Your bold new edits are welcome too, but it's time to discuss them here now, and there are several problems with them. There is of course no problem with including sourced statements about the limitations of solar energy for human use. In the first instance these should be added to the sections on "Energy storage methods" (which should be renamed "Energy storage") and "Development, deployment and economics". When we're sure that those sections are a balanced reflection of current thinking about the possibilities and limitations, then we should make sure that they are summarised in the lead para. In the present wording, "perishable" and "nascent" simply aren't appropriate for a science/engineering article. So, Amspock, I suggest you think about the sources that you want to use, and add material based on them to the appropriate sections. Thanks. Itsmejudith (talk) 08:22, 23 January 2009 (UTC)

Note: User:Amspock is now A M Spock. Apteva (talk) 21:57, 2 February 2009 (UTC)

I would recommend deleting the last paragraph from the lead -

"The biggest limitation of solar energy is that it is perishable in the extreme and neither in its nascent form nor as electricity can it be stored efficiently and economically for use when needed."

as solar energy is neither perishable, nor can electricity not be stored efficiently and economically - we do it already in the form of pumped hydro-storage, and solar power is stored in nature in the form of biomass.

I would recommend changing the third word in the lead "is" to "utilizes", bearing in mind that the article is not about the energy from the sun, it is about how we use the energy from the sun. Also I would like to see the words "solar power" in the lead section somewhere. For that I would suggest in the second paragraph changing "Solar energy technologies" to "Solar power", making it bold. That also has the advantage of not duplicating the word "technologies", which appears in the third paragraph. 199.125.109.37 (talk) 14:44, 23 January 2009 (UTC)

Agreed, I think, at least they are reasonable suggetions to discuss, but ...User:Apteva ... please use your account. Itsmejudith (talk) 19:13, 23 January 2009 (UTC)

99% of my edits are as an IP user, at least they were until recently, and I'm trying to get my percentage back up. It had slipped to 92%... Apteva (talk) 02:40, 24 January 2009 (UTC)

I tried out some alternative wording that is intended as a compromise between Apteva's approach (the article's about solar power) and the view of various others (the article's about solar energy in general and its technological applications in particular). Since I was last actively involved with the page, some statements seem to have crept in that open up issues about the viability of renewable energy in general, not just solar. For example there is a complaint about biomass overuse. It seems to me that the unavoidable points about solar energy qua renewable energy are as follows. 1) Solar energy is regarded as a form of renewable energy. 2) Some other renewable energies, notably wind, hydro and biomass ultimately derive from solar energy, but are separately classified. 3) Solar energy is intermittent energy because it is reduced in cloudy weather and unavailable at night. 4) Therefore storage is important. 5) The amount of energy reaching the Earth's surface from the Sun is in principle vastly larger than human energy needs. 6) at present only a tiny proportion of the energy available through insolation is used by solar energy technologies, although every single thing we do depends on it (having water to drink, food to eat and an ambient temperature that's usually between -40 and +40 C).

Is the above the basis for a short para somewhere near the beginning on solar energy as a renewable energy? Itsmejudith (talk) 19:51, 23 January 2009 (UTC)

I would separate point 2) out as an aside somewhere, and not an essential element of the article - it is a truism, but it does not affect the subject of the article, which is how we use solar energy. I would leave out the portion of 6 in parentheses - the article certainly does not need to outline conditions for life. Apteva (talk) 02:40, 24 January 2009 (UTC)

Many thanks. I am glad we have a discussion going now. The idea of bold edits was to start one and I had made my intention very clear before I started. I think there are some really basic issues at stake here. To start with I agree that references to life support role of solar energy probably belong elsewhere. (Having said that it is rather more than support, it is the driving force.)

1.While the subject is scientific the medium is for the lay person. It should use simple language. Scientific journals do a pretty good job of using turgid and obfuscatory prose. The tests in this medium should be accuracy, simplicity, comprehensibility etc. While linguistic frivolity is to be avoided, let us not have arbitrary standards of appropriateness. So Solar energy apart from being intermittent is also perishable. Perishable: meaning whatever is not used is gone forever. Perishable in the extreme means gone instantly. Nascent: As it comes into existence. It is renewable only in the sense that a fresh lot is born every day.

2.If this page is limited to solar power/energy technologies only why not say so up front? First there is the Sun, then there is the Solar energy radiated by it. Then there are technologies deployed to harness the energy. Then there are the technologies deployed to store the energy not immediately consumed. We can not title the page Solar energy and then limit everything to incomplete discussions/ descriptions of some but not all technologies.

3. Any discussion on any technology is incomplete and misleading if it lists the benefits without pointing out obvious limitations. In the case of solar energy these pertain to spatial and temporal mismatches between availability and usage and hence the need for storage. At this point in time there genuinely appear to be few, if any, storage systems for heat or electricity that make sense in economic or efficacy terms except in remote locations or under extreme or special circumstances. If there are any commercially viable systems, why are they not cited here with appropriate links? Surely it is impossible to cite a source which will confirm the absence of a universally viable heat or electricity storage technology!! There can only be a positive or affirmative citation. There is so much universal interest in this topic that readers want to know when and how they can use the various technologies they keep hearing or reading about.

4. Those who write about solar and other forms of alternatives are often seen as evangelists unwilling to look at limitations and determined to proceed regardless of cost or convenience. This leads to some loss of credibility.

5. Biomass is an excellent natural store of solar energy: I had said so in my edit. But someone took it out. Many of the problems or issues pertaining to biomass use/overuse of biomass could have been avoided if the downside had had a fair number column inches.

5. I think we do need to state upfront that while there is a lot of talk about solar energy, in fact a very tiny fraction of our needs is currently met from this source. I had done so but again someone has taken it out. added by A M Spock (talk • contribs) 06:40, 24 January 2009 (UTC)

1. I see you are quickly getting the hang of having your contributions mercilessly edited.
2. Biomass is a secondary result of solar energy and is a separate form of renewable energy from solar energy. As I said before, while it is a truism that almost all other forms of energy come from the sun, that is not the subject of this article. The subject of this article is how we use solar energy.
3. We passed the idea of solar power becoming a credible energy source at least 20 years ago. It is a billion dollar/year business today, soon to become a trillion dollar/year business.
4. If you poke around at some of the other related articles, such as intermittent power sources you will see how electricity can be efficiently stored in pumped hydro-storage. Not sure why you keep bringing up that it can not be stored. If you look at deployment of solar power to energy grids you will see that Al Gore's idea was to bring power over from Europe using a transcontinental grid - the sun is always shining somewhere. You might be interested to learn from that article just how little contribution solar power makes today - and how quickly it could become dominant. I don't think Barack Obama had a clue what he was talking about when he said that we were going to get 10% of our electricity from renewable resources by 2012 (the US already got 10% of all energy from renewable sources back in 2007) or when he said we are going to double our use of renewable energy in three years - what go from 12% to 24%? Katie bar the door if that is going to happen. I'll need more than a slide rule to figure out how to do that miracle.
5. The main point about making "solar power" appear bold in the lead somewhere is that there is no solar power article, this is the article on solar power, and was named "solar power" for the first several years of its existence. There are literally hundreds of links to solar power and there is no guarantee that the person clicking on them knows that there is any relationship between power and energy whatsoever, so by making solar power bold in the lead it just lets them know that they have arrived at the correct article they clicked on and didn't get totally diverted to some totally incorrect location. It does not make any difference where or how it appears in the lead, it just has to be there and has to be bold. From a "brilliantly written" point of view, it obviously makes a great deal of difference where and how it appears. Apteva (talk) 07:09, 25 January 2009 (UTC)

I think we are in agreement on almost every stated thing. 1. I have no problem with bold 'solar power'. The current edit deals with this fairly well. 2. I do not say that bio-mass belongs in this article. It was there when I came in. It is only tangentially solar based. By that standard everything almost is. I only said that it was distinct because it was a natural store. 3. It is a truism that anything can be stored. And transported. And yes I am aware of what is happening in this area. But also of what is not happening. At what cost and what efficiency is the question. 4. Or maybe there is some reason all the light and heat incident on the Sahara is not being converted/ stored/ transported to northern Europe where it would support a life of comfort or Bangladesh where it is sorely needed to support life. 5. Credibility of solar power technologies is beyond question. Their time will come is also beyond question. Viability for them is what concerns the vast majority of readers, and indeed the citizens who are literally dying for power. In Bangalore the tech capital of India and probably the richest city in the country, Government hospitals have been known to carry out surgeries under candle light or torch light. This in 2009. If there is a reasonable way to get the power let us do it pronto! Or let them eat cake! A M Spock 20:01, 25 January 2009 (UTC)

The main ways solar energy is stored in current technologies are:

1. thermal mass of buildings
2. hot water in tanks
3. batteries.

If this isn't already clear, then we can look up one of the main sources and clarify it from there.

OK, we have to write for lay as well as expert audiences (but compare some maths and stats articles to see how accessible they are). "Perishable" is a nonsense in physics terms and reads very oddly for a lay audience. Fresh tomatoes are perishable, canned ones less perishable. Itsmejudith (talk) 23:45, 25 January 2009 (UTC)

The above are the ways solar energy is stored on a local scale. On a utility scale the three technologies that are used are 1) pumped hydro-storage 2) compressed air and 3) batteries (usually "flow batteries"). Other technologies that have been proposed are centrifuges and V2G. Pumped hydro is by far the biggest scale form of storage, and is used quite a lot today. Typical pumped hydro facilities can provide upwards of 1,000 Megawatts for up to about 19 hours.

The IEA has a Task 8, very large solar,[1] which is investigating projects such as covering the Sahara, and India has set aside 35,000 km^2 of the Thar Desert, the only place in the world that plans of that scale have been codified, as far as I have been able to determine. 35,000 km^2 is a lot of solar power. Apteva (talk) 04:15, 26 January 2009 (UTC)

We are going around in circles. Nonsense is a very strong word. I don't think it belongs in a civilised discussion. But perishable is a concept straight from physics so is decay. Tomatoes are perishable because they decay over time. That is why they are canned. At a cost. In India and other less affluent societies tomatoes, as also other fruits and vegetables, perish every year by the millions of tonnes because the grower has no means to can / otherwise preserve them and no cold chain to deliver them to a canning facility while at the same time ensuring that the end product would have a customer at a price that makes all this worthwhile. A lot of stuff is actually 'sun dried' in these economies. This is true current, and from time immemorial, use of solar energy and finds no mention any where but 'daylighting' does.

Sure at some point of time in the future solar energy captured, stored and transported to the user will be a saviour. I look forward to that day as much as the next woman. But I am also pragmatic about what is happening right now and I don't want the reader to think that salvation is around the corner or indeed here. For those who need power now, investigating, setting aside and quite a lot have no significance. Where is the beef?

As I said earlier, the fact that storage technologies exist is not in question. So there is no point in harping on the same thing again and again. What is very much at question is the cost and efficiency associated with them at present. This will surely improve as we go along but we are a long way from there. There is no harm in acknowledging that. Ideally one should be able to point to a broad time frame or conditions precedent to such technologies producing power at costs comparable to fossil fuels. —Preceding unsigned comment added by A M Spock (talk • contribs) 15:52, 26 January 2009 (UTC)

Sorry for "nonsense". I'm happy with "intermittent power source" in the lead, and if others aren't we could go to the Physics Wikiproject again for some further opinions. I would also be very happy to see sun-drying of food in (with the washing-line if it is still around), and a mention of sea salt pans might also be appropriate. What this article shouldn't do is to cover the whole debate around renewable energy; we shouldn't hide the fact that there is such a debate, but link to the articles that cover it in the right depth. It seems to me that this an engineering article essentially, which is why it's OK to begin with the basic science and then move on to the technological issues, finishing with the deployment. The temptation to turn it into "solar power: for and against" has bedevilled it for ages, and we need to move on. Itsmejudith (talk) 18:08, 26 January 2009 (UTC)

Setting aside any inflammatory language, does anyone see any edits that should be made to the current article? The main issue that I see is the question above, about moving the article toward feature article status, by using summary style. Also, when one adds something to a talk page, any talk page, please "autosign" your comments by adding four tildes, like this: ~~~~. There is also a button at the top of the edit window you can use, the one with the squiggle in it which is supposed to look like a "signature", just to the right of the red circle saying "no W" (nowiki) and just to the left of the bold dash (horizontal line). And once again, everyone's comments and edits are very welcome. It truly takes a village to build an encyclopedia.

With regard to "point to a broad time frame or conditions precedent to such technologies producing power at costs comparable to fossil fuels", I would look to see if the buzz words "grid parity" exist in the article somewhere. Guess not. There is a good graphic that BP created showing the drop in solar prices and the rise in electricity prices to show this cross over, and there is a link to it in the references of the photovoltaics article - search for "(Graphic)". I would keep the reference to cost rather subtle. Complicated factors have prevented reality from being as smooth as the graphic would indicate, though it shows a band for pricing that is well within reality. The proper place for more detail on PV pricing is in the photovoltaics article. I think that solar hot water projects are highly cost effective, and I have been told that they are universal in Israel (though perhaps not in the Palestinian occupied regions). Apteva (talk) 19:17, 26 January 2009 (UTC)

Thanks. We have come a long way. I agree this is not the place for a for and against debate. But do let us by all means provide very brief references to cost and time frames and links wherever available. As long as it does not look like we have our heads collectively buried in sand on this aspect. I would prefer if someone else had a go at it to ensure that it remains moderate and modest.

Yes the washing lines and salt pans are very much alive. Something like 99% of India, China, Bangladesh and Pakistan's laundry is sun dried. Even Hongkong has laundry lines protruding 20 feet or so from many hi-rise apartment blocks in the less affluent parts. These are countries I know intimately. Most of the salt in these parts comes from salt pans. So is such food preservation as exists - fruits, vegetables, fish, pickles, potato wafers, extruded wheat, rice and gram flour snacks. The fabled Bombay Duck is in fact invariably sun-dried by the road-side.

Yes solar water heating is economically and operationally a viable options in many parts of the world. In these very parts photovoltaic power is a joke, except in locations which are at least five km away from a grid, and in some cases that I have personal knowledge of, a fraud. And battery storage of electricity with lead acid batteries is fraught with all kinds of issues on pollution, while other kinds have cost issues. In the photovoltaics article there is a link to lead acid issues.

p.s. i sign my comments normally with the 4tildes else they get auto signed because I login first before I write anything.. A M Spock 05:36, 27 January 2009 (UTC)

Somehow your four-tilde signature isn't working. Yes, I knew the washing line exists in real life - I wasn't sure if it was still mentioned in the article. Greece is another country with very widespread use of solar water heating. It's great to have a world-wide view in the article, which at one time was rather US-centric. I don't think we will be able to say much about fraud. I'm sure it exists because in the UK there are many companies marketing solar water and/or PV to individuals, the regulation is loose and they are regarded with about as much confidence as double-glazing salesmen (i.e. very little confidence). You seem to be saying that PV is over-sold in parts of Asia, and I can believe that, however, 1) one-off PV items are coming on the market, e.g. lamps, radios - they are likely to improve to the level of the calculator, which everyone accepts as useful 2) eventually grid-connected PV and net metering will come into the cities. In the meantime, are there not quite a lot of locations more than 5 km from the grid? I know that in the mountains of Spain and Portugal households may use PV, perhaps in combination with a wind turbine or a small hydro generator.

Apteva, yes I was thinking of local storage, which will continue to be important. Of course you're right that utility-scale options are coming into use quickly. Can you ensure that the pumped hydro etc. is dealt with adequately using good sources? Thanks. Itsmejudith (talk) 11:14, 27 January 2009 (UTC)

Clotheslines are such a ubiquitous and simple use of solar energy that it would be ok to include in the lead. They are mentioned in the article body. Added a bit about the need for backup, and a sentence about the combined power plant that was tested in Germany about a year ago. I think what happened is someone told Merkel that all electricity could be obtained from renewable sources and then set out to back up the statement - successfully. Amspock: Your new username is A M Spock. Try logging in as that instead. Apteva (talk) 20:13, 27 January 2009 (UTC)

section break

I think we are way past the stage of either debating the credibility of solar energy technologies discussed in the section or quibbling about which specific passive tech uses to mention in the lead. I would like to say in the lead that "Solar energy technologies currently in use or under development have the potential to progressively release us from the tyranny of fossil fuels and the accompanying global warming and pollution consequences as they achieve a. critical quantitative mass, b. improved capture, conversion, storage and transmission efficiency and c. greater commercial viability." A M Spock (talk) 15:19, 31 January 2009 (UTC)

I would call that far too, how do I say this, promotional, for an encyclopedia. Think of what an encyclopedia is. Think of those volumes of seldom used books in every library that people use for a reference. The purpose of the encyclopedia is not telling what could be as much as to show what it is at the moment. Potential gets into trying to be a WP:CRYSTAL BALL. I have no problem with showing the potential, but telling the potential is different. One of the tenets of WP is to show not tell, and to not editorialize. This is not a white paper, but an encyclopedia. Apteva (talk) 21:09, 31 January 2009 (UTC)

The whole thing is so gung ho about solar energy, the first time I read it I thought it was a paid promo for some interested parties. The reason I want to say what I suggested is to point to the fact that while we will get there one day we are far far away from being able to compete with fossil fuels unaided by tax dollars of Tom and Jerry, except in some extreme situations. This is INFORMATION, not editorialising. The funding by the poorest of the poor for the whims and fancies of the richest of the rich finds mention. The fact that much of it is essentially experimental stuff does not. Letting subsidised capital feed the grid at twice the rate of leeching the grid to appease those who would like to see some action that looks green is the dumbest economic policy ever.

When we say that xyz is growing at 100% per annum, and that costs are coming down as volumes grow, surely it will get somewhere to a point where it crosses something for which availability is shrinking and costs rising. That is not crystal ball gazing that is basic stats.

A M Spock 07:27, 1 February 2009 (UTC)

Also to reply to someone who said that there must be users more than five km from the grid, yes there are. basically remote communication and research setups, bot civilian and defence. The common man who is more than f km away is normally one who can't afford the product.A M Spock 07:27, 1 February 2009 (UTC)

Well as you will see above the purpose of this talk page is to discuss the article, not the subject, although there is an inherent cross pollination - the question always being, is the article complete and accurate? So, Cuba and India come to mind as locations with many people more than 5 km away from the grid who are now quickly being supplied with solar power. India in the form of many solar lighting projects, Cuba, because that is the official government policy. I do not see the need to go overboard in mentioning either in the article, but they should also not be avoided. It is particularly important to make the article represent a worldwide view, and not be U.S. centric, for example. As to the article reading like a brochure, that is useful criticism, and needs to be addressed. My own opinion is that the article tended to downplay solar energy. "Far far away from being able to compete with fossil fuels" is inherently an opinion, but can easily be quantified with reliable sources and makes a useful contribution to the article. It is trivial to do a rough calculation of the investment required, and I am sure that there are many RS's that are available. Solar is fundamentally different from a non-renewable resource in that you pay for all you ever get up front and it lasts forever, vs. you pay as you retrieve it until it runs dry, so the economics are very different. For example, were the central bank of a country to lend a bazillion dollars to build solar panels, the result would be that they would be paid back with interest. On the other hand no central bank needs to lend any money for development of oil, because all the oil that will ever be produced is already being produced, and is already providing an income stream, an income stream that is non-existent for solar power today. However we also live in a very dynamically changing world, so the article needs to be updated to reflect whatever is the current status, and provide a history of the development of solar power. By the way, the "common man" in India typically pays in one month the same for Kerosene for lighting that it costs to purchase a solar lamp that then provides lighting for free for the next twenty years. One of the worlds economic principles is to keep people poor so that they will have to keep buying stuff from you. Not a very well thought out principle, though. Apteva (talk) 19:36, 1 February 2009 (UTC)

Fixed links due to change of username. Apteva (talk) 21:57, 2 February 2009 (UTC)

Dynamic or not, we seem to live in different universes. 1. India's current solar output is 5MW and total solar power generation target upto 2012 is 50 MW. http://www.rediff.com/money/2008/jan/03power.htm. At this rate taking 100% growth per annum the all India deficit will get covered by the year 3009. 2. The power deficit in the city of Delhi in summer is 800MW in fall 300 MW http://www.expressindia.com/latest-news/power-shortfall-of-300-mw-delhi-overdraws-despite-warning/368506/ Solar power generation cost for localised consumption (based on quote from a Bangalore maker using Bangalore produced BP Solar panels with capital cost converted to annual costs based on 20 year life for panels, 10 years for inverter and five years for battery + minor maintenance costs) is Rs. 15 per kwh for solar and Rs. 4 for grid. It costs Rs. 60 per month to run a kerosene lamp for one month @ 4 hours per day. Assuming a 15W CFL lamp will do instead, the capital cost currently would be around Rs. 15,000/- for a four hour system. That is 250 months worth of kerosene. and very roughly Rs. 250 or so per month amortised as above assuming a 10% interest rate for capital. And yes I want him to use solar power. But he can get it only if someone else pays for it. Finally any reference to where we are headed is only a nod to the fact that we do live in a dynamic world. A M Spock 05:26, 4 February 2009 (UTC)

ps. this discussion is still about making the article more informative. and many thanks for fixing the name change hasslesA M Spock 05:26, 4 February 2009 (UTC)

Under "my preferences" I think you may have checked the box "Raw Signature". Please note that it warns that "If checked, the contents should be formatted with Wiki markup, including all links". I would suggest unchecking it. Otherwise you should format your signature with links to your user page and user talk page. A couple of quick points about your math. First, as you point out, going from 5 MW to 50 MW in 3 years is close to 100% growth, 115%. However, going from 5 MW to 800 MW at 115% growth rate only takes 6.6 years (but add a couple more because that is 800 MW at 100% duty cycle vs. 800 MW at 20%). Einstein called compound interest the eighth wonder of the world. Also, the solar lamps are LEDs, which use 1/4th the power of CFL - typically 2 watts or so. I think they were selling the lamps (which include a solar panel) for Rs 600, but that is just a wild guess, I would have to check. They were selling them at an unsubsidized price, but also selling at cost I believe, which is about 1/2 to 1/4th typical retail price. Check the Solar power in India article. Nope, needs to be updated. I believe that tens of thousands of lamps have already been delivered. Apteva (talk) 07:19, 4 February 2009 (UTC)

800 mw is the shortfall in Delhi the capital city alone!! India is slightly larger. just as the u.s. is slightly bigger than wash d.c. also, i am aware of the l.e.d option, but have not looked at the costs. i am in the process of getting actual current quotes. will update the figures in a day or so. also just unchecked the offending box. many thanks for your help and guidance on the admin stuff. A M Spock (talk) 17:14, 5 February 2009 (UTC)

Glad to see you have sorted out your username. The data should go into the SP in India article. With compounding, even a 41% annual change doubles every two years. There is Chinese have a saying for change, "we live in interesting times", implying that change is not good. However, the change came a hundred years ago, we are just cleaning up the mess it created. I think that SP in India already indicates there is more than enough potential for solar power. The Solar power in Alameda County article indicates that Berkeley has come up with an innovative way of paying for solar panels - add them to your tax assessment, so they can float a bond to pay for them, and you get them installed for free at no cost to the city. That is what I was referring to above about loaning a bazillion dollars. LEDs are so much more efficient than CFLs that they are a necessity, not an option, considering the cost of the panel would increase by a factor of four for the same amount of light. White LEDs have recently come down a lot in price. Apteva (talk) 18:06, 5 February 2009 (UTC)

May you live in interesting times says it's probably not an actual Chinese saying.

—WWoods (talk) 00:38, 6 February 2009 (UTC)

sorry for the long absence. thanks but yes i do know something about compounding. a post grad degree in maths and stats helps a bit. and yes the earlier target date for india of 3009 still stands. i will put the data in appropriate places but in brief, the cheapest non-toy sold in india is a 4 l.e.d., 12 volt system (equivalent to 25 w incandescent bulb) costs around rs. 9,000 or u.s.d. 180 or so. the cheapest household set to provide three such units with an autonomy of two days costs rs. 36,000 or u.s.d. 720. cheers. A M Spock (talk) 10:50, 11 February 2009 (UTC)

Solar Energy

Solar Energy is used in many different ways....Some people use it for electricity to light and heat their house's.Some People may use Solar Energy to get energy for cars or other things. --173.23.174.119 (talk) 16:18, 27 January 2009 (UTC)

Solar Energy uses....

This Section is about How and what ways solar energy can be used...Solar energy can be used to power house's by giving them electricty and heat...some or most people use put Solar panels on their roof's so they don't have to pay for electricty. I think using solar panels will become a big help some day...If we all use it it would be more money for every one to keep and use for other stuff.--173.23.174.119 (talk) 16:27, 27 January 2009 (UTC)