Solar Power Extracted From Photovoltaic Cells

Most (Si) based Photovoltaic cells can produce roughly a half a volt regardless of its surface area. A larger surface area will produce a larger current but the same amount of volts. To have any practical use several cells would need to be connected in series. Their are some new materials being brought to market in limited quantities such as gallium arsenide that state better results but I have not seen any official data that I would trust just yet.

I think solar power will have a great promising source of energy-question of time.

Legislation may be introduced to install solar power generators for the new large complexes so as to avoid supply of grid power.

That may be so but I feel that the photovoltaic model is just the ground floor for this technology. It is true that the technology has been around a while but much like the slinky, it was cool to play with when you first got it but after a while you got another toy and decided to stick the slinky on the shelf. Well now there is a popular demand for it and new companies are springing up creating what should have happened long ago, competition! Through competition technology companies always want to be the first so resources are poured into R&D and new methods are applied to the old idea. What the next step is going to be is hard to say. But I know that this is just the beginning. New materials are being tried, new design structures, HE Particle simulation and computer models, the list goes on and on. So we are in agreement on some level because these things take time to develop and made to be cost efficient, but in the end the potential you speak of definitely won't come from our current traditional methods. Right now I know Hewlett Packard is working on a stack design to utilize more areas of the spectrum source. This should enable it to produce several times the voltage and a slight increase in current over present methods. As well as conserve space. It has all the promise of the next step but we'll see if the follow through with it or it leads them to somewhere else. If you felt that this comment helped you better understand the subject matter rate it please. If you have other questions please feel free.

I was involved in establishing Solar Photovolataic technology manufacturing facility around 1984. I can give some idea, but not aware of latest.

Even in silicon - you have monocrystaline, ploycrystaline and amorphous technologies. Each has its own + & -. Monocrystaline is preferred/ popular for power generation (jsutification will run into pages etc).

Sunlight itself vaires across the globe depending on lattitude and logitude and season and weatehr conditions(dust, cloud, water avpor, pollution etc). Thus what is specified is output under certain ideal sunlight condition -as for testing solar panels tehy have to use ceratin artificial light with certain spectral distribution. So when you buy such a panel - what volateg nad curernt you will get at the output will depend on so many real life condfitions. So manytimes i have felt that all lab resulsts and field conditions can never be matched and you can never go back to manufacturer and make counter claims.

Then comes construction of panel itself using solar cells. Then the diameter of the cells (if round) or rectangular. if round- then there is loss of space or area or sunlight capturing suraface. If rectangular - sunlight capturing surface goes up, but manufacturing losses go up. So this idaelised sunlight is considered as input power, and output voltage x Current is output pwer. Thus panel efficiency is around 30 % or lower.

Output of silicon monocrystalline cell is 0.7 volts (no current drawn) = Open circuit condition. Then there is short citrcuit condition where cell deliveres only current when output is idaelly shorted with thich wire. But operating point is around 0.5 volts & current depends of area of cell.

Manufacturers sell 12 w, 24 w, 36 w, modules. Voltage & current depends on number of cells in series and parallel. For every simple statement I have made - justification runs into many pages.

Good Relevant Answer Awarded for actually knowing that "power" which was the original question is measured in WATTS. and being first to provide answer of module wattages so OP can do calculations. nicely done.

Power is actually the rate at which Work is preformed or energy is converted over Time. So we can make the following statement (P)average = Delta(W)/Delta(T) or (W)= (P)x(T) in this later equation (E) can also be substituted for (W). To use the value for instantaneous power as (P) to be measured in joules per second where 1(J/s) = 1 watt you need to account for more variables such as current (I) measured in amperes and voltage drop (V) measured in volts where (V) is also known as potential difference across the component. Given this we can make the statement that (Pt)= (It)x(Vt) as functions of time. One can not convert volts to watts directly you need to account for the amps of the system. Amps are how many electrons flow past a certain point per second and Volts describes how much force each electron is under. With that being said and looking back at the original question we can see why giving a response in watts for the Power extracted from "a" (meaning single) photovoltaic "cell"(also singular) is in fact wrong. Increasing the amount of cells will increase both current and volts but this in fact only gives you a greater potential to do work or greater energy. This also complies with the original statement because Solar Power is the generation of electricity from sunlight and electricity for this case is Electrical Potential and this is measured in Volts. I hope the earlier equations help better explain my point and generalize what can turn into, as M S DIVEKAR put it, pages of justification.

France is planning to build a large solar plant in North Africa and from there to transmit a clean power to France.

Thanks for your responses I have extracted and article below from Sde Boker makes solar energy viable: http://www.haaretz.com/hasen/spages/890970.html Has anyone heard of this type of photovoltaic cells? In an ordinary solar panel of the type in use today, the silicon that makes up the cells is very expensive, making it a costly product. According to Feiman, photovoltaic cells carry out two functions: First, they change the light into electricity, their essential task; second, they store the light. "The principle is to focus the light using little material," Feiman says. "We constructed a large, parabola-shaped glass plate. It not only absorbs the light, it also focuses it on one point, a thousand times more than regular sunlight." According to Feiman, "an ordinary photovoltaic cell, which is 10 by 10 centimeters, normally produces one watt of electricity. We managed to extract more than a thousand times more - 1,500 watts. In this way, the cost of a cell is 1,500 less, becoming almost nothing." "No one has ever produced so much electricity from a solar cell at this strength," he says. he Solar Energy Center is now collaborating with an Israeli start-up company, Zenith Solar, to create a home system of solar cells based on this technology within about a year. "What is good for the home is also good for the country," Feiman says. Israeli solar energy technology is already used extensively in power stations throughout the world. At the center at Sde Boker, which belongs to the Jacob Blaustein Institutes for Desert Research of Ben-Gurion University of the Negev, two solar panels are installed, each one about 100 meters long, moving in synch with the sun. An oil pipe is at the center. The panels, built by Sollel, a Beit Shemesh company, are not based on photovoltaic cells, but rather focus the light on the pipe, causing it to heat up. Heat produced by panels of this type turn into steam, which moves turbines. Last month, Sollel signed a contract with the U.S. company PG&E, to build the largest power station in the world, in the Mojave desert in California, which will have about 7,000 such panels and will cover about 14 square kilometers. It is due to go into service in about four years, providing 553 megawatts of electricity. The British-born Feiman has lived at Midreshet Sde Boker since 1976, when he began researching solar energy. A world expert in the field, he says the economic model he has built will allow a significant part of Israel's energy to go solar within the decade. "We're paying about 10 cents per kilowatt/hour. If the government taxes the Electric Corporation one cent per kilowatt/hour, it will amount to about a half billion dollars a year. In a decade, we won't need any outside funding. If we want to solve Israel's energy problems, we should stop building conventional power stations and build a solar power station every year of one gigawatt - equal to two of the type of station Sollel is building in California." The National Infrastructure Ministry said it would "soon be determining electricity rates for home photovoltaic systems. At present, the parties are working on removing obstacles that have to do with land use."

WOW! This is something so obvious that we should have come up with it. Amazing use of energy. We have all probably played with a magnifying glass and burned something with it. Same theory here. They are harnessing the heat element and using that to do work by heating fluid to steam and driving turbines. Pure genius. This is the first time I've heard of this and it makes perfect sense. I've been hashing out some equations and found that the results are right on point with his statements in the article. I must have slapped my forehead a thousand times for not seeing this before. Thanks for the article I'm going to share this with everyone I can't wait to see their reactions. LOL

When i was child i used to use a magnifying glass to focus the sun light to burn a piece of paper.

I had the same idea in my head for long time as possibility to get energy by that way but now it became a reality.

You need to purchase the KrisDel (tm) Sarcasm font.

Ask Del the Cat.

milo

Thanks I'll look into that..... because most of the time it goes unnoticed.

You should see the solar furnace at White Sand Missle Base in New Mexico. They've been burning holes in 1 inche steel plates for 30 yrs.

I'm hoping there is a valid advance here, but it reads like just another cold fusion media crapstorm.
The basic concept is very OLD. Applying concentrators to solar cells has been around for some time also.

http://en.wikipedia.org/wiki/Concentrating_solar_power#Concentrated_photovoltaics

I don't understand how they can get a patent on something that has been in use for decades. The "new" development could be more about an advance in the solar cell itself, but detailed data is limited. If they have an improvement in the cell, that would be a good candidate for a patent. At 1500 suns, any normal solar cell would need substantial COOLING or it would quickly burn up. Maybe their cell can run safely and more efficiently at higher temperatures? Let's see what develops.

I hope it isn't a crapshoot and I have extracted another article from Business Week about the firm who are planning produce these solar cellls: OVERSEAS OPPORTUNITIES Once these projects are operational, Zenith plans to start commercial sales in Israel in 2009 and then to go abroad, says CEO Segev, a 46-year-old entrepreneur who is one of the growing number of Israel's high-tech elite getting involved in renewable energy. The company is already planning a range of products that would be adapted for household, commercial, and industrial users—and even entire neighborhoods or communities. The price tag for a home-size unit is likely to be less than $20,000. If that price tags holds true this would be a godsend that is really cheap. Since I have not seen the company's plans for this product it may be awhile before it is on the market but I surely would be interested in reviewing in it for its adaptability in our climate.

The FUNDAMENTAL problem with all of these system is the cost-payback time. At US$20,000 it is still a factor of 10x too expensive.

My home is 2 story, 1500 sq ft, 100 years old , and uninsulated ! As lossy as it is, electric cost (including electric hot water heater), is $720/year (average about 500 kW-hr per month). At this rate, it would take 28 years for a US$20,000 system to pay for itself. This just isn't even close to practical. Even with a government subsidy for 50%, the 14 year payback is still unacceptable. Add maintenance and replacement costs and none of these systems are acceptable alternatives.

Those with much higher utility costs might benefit, but IMHO the mass market for alternative power won't be interested until cost-payback drops down to the 2 - 4 year range.

I guess I have been lied to all my life,

People have ALWAYS told me that NY state is expensive place to live.

I have 2200ft^2 2-story home, ~40 years old, well insulated, sealed thermal windows, gas utilities for heat and water heater, and my electric bill is ~$110 / month if I am Not running my pool pump. Maybe another $30 if I am.

You're right, what you are paying for electric won't justify photovoltaics.

milo,

For a number of years, now, I intended to use photovoltaic systems and solar heating. I have (due to diligence of Global Specs) contacted some twenty Chinese companies, all manufacturers of photovoltaic cells. I don't mention quality concerns, only price concerns, and Chinese are offering the lowers cost/kW. I also have built a copper tubes and plate system for heating the water in my jacuzzi. I am a fan of using the solar energy. And what you were saying was so attractive.....

What did I want to say? er...r....r.....

Ah, yes! From the Sun, at the ground level, with the rays falling almost vertically, the energy we can have is 1000W/m². Now, the conversion is about 15% efficient (more or less) so, a square meter of Photo Voltaic panel gives you 150W electric, and , of coarse, some heat. Referring to the square decimeter (ten by ten centimeter), the output would be 1.5W electric.

Your friends in Israel would get, from the same dm², an energy 1000 larger. From where? From what I know, the last miracle was, in that area, a bit less than 2000 years ago. To concentrate the solar rays on a smaller surface it is, now, a known fact, Physics4Every1 has verified himself. But 1500W out of a dm² PV cell, don't you think that is a bit....exagerated?

Can anyone tell me just how long you can expect to get power from PV Cells. Are they indestructible or do they need to be refurbished from time to time? Do some last longer than others?

20 year according to this excellent report:

http://css.snre.umich.edu/publication/life-cycle-assessment-33kw-photovoltaic-system-dana-building-university-michigan-thin-fi

Their cells had 20 year warranty.

One issue is lower output when they get obscured by dust debris etc.

An occasional sweeping or cleaning is what my buddy does every month or so in Michigan to remove the grime, bird droppings and drifting walmart bag that snags on along an edge. I imagine in a very dusty or airborne pollutied environment this might need to increase in frequency. I thought that i had read of some systems with impulse air wipers, but can't remember my source...

Vandals and other casualty losses also to be accounted.

milo

A rule-of-thumb for sizing calculations is "around 5% of the energy falling on it".

It seems to me that it would be a good idea to have laws put in place that would require every new house built to have to put a pecentage of its original selling price into renewable engery, such as solar electric, solar water or wind turbines...

If home builders were required to add 5% to the selling price on a $150,000 home this would require $7500 to be put toward a solar panel or other renewable energy producer. So now the house would cost $157,500. The over all house payment would go up very little. Less than $50 per month.

The home owner would probably save at least half of that or more on their electric bill each month.

$7500 would not buy enough solar panels to power an average home with todays technology but this would send a lot of money toward renewable energy that would quickly drive the cost of production down and soon $7500 could possibly be enough to power a house within a couple of decades.

This would also slowly start taking a little load off the power grid.

The 5% does not have to be on sight either. It could be used to buy into a windmill located out in the desert some where. This would be good for people who have houses in areas that are overcast most of the year and don't have favorable wind conditions.

I get confused with so many posts referring to using lenses, solar concentrators etc etc.

The original post says " What is the greatest amount of solar power one can extract from a Photovoltaic cell?"

As an electronic engineer I believe that Silicon as a semiconductor junction cannot operate beyond 200 Deg C. Many transistors etc have max operating junction temp of 150 Deg or lesser. Same applies to solar photovoltaic cells. GIVEN THAT - when someone is referring to magnifying solar energy using concentrators to about 2300 Suns etc - it is not with solar photovoltaic cells, but with solar thermal energy generators- where water or some other medium could be heated to as high as 600 or even 1000 Deg C to run turbines.

So please do not confuse between two different applications of solar energy.

My specific reference is about solar concentrators FOR photovoltaic cells. If you bothered to read the link and took any effort to study the subject, you would understand that solar energy can be focused onto small area cells AND that the electrical power output and efficiency increase under these conditions. Limiting cell temperature IS critical, but this is addressed by proper cooling techniques.

Solar concentrators ARE part of the answer to the OP's question. More light = more power form the cell! Please try to put a little effort into understanding the topics discussed before posting.

Did raed up this link- but also read a few more confusing comments in this thread - where people are referring to temperatures going higher. So my comment was referring to those confusing statements in the same thread..

I agree! Some people see the term Photovoltaic and think that this is some blanket term used to classify all forms of solar conversion. This is not the case as you point out. For anyone else please understand Photovoltaic cells convert sun light directly to electricity by the photovoltaic effect.(Hence the name) The other forms discussed are STE or Solar Thermal Energy converters and are used to heat pools, homes, and businesses as well as operate, as the USA Energy Information Administration classifies, as High-Temp collectors and these heat fluids to drive turbines and have really no relevance to the question asked.

If the energy generated causes a very high temperature and cooling technique is required for the photovoltaic cells ,why thermocouples are to be used instead of photovoltaic cells ?