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Breakthrough Reported on Low-Cost Alternative to Silicon Solar Cells

post #1 of 11
7/8/09 at 10:11pm
Thread Starter 
Quote:
Solar cells could be produced from materials other than silicon under a breakthrough that scientists at the University of California, Los Angeles, say could dramatically reduce the price of solar technologies.

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"With the solution process that we recently developed, we can inherently reach the same [20 percent] efficiency levels and bring the cost of manufacturing down quite significantly," Hou said.

{...}

Yang said the technology could reach commercial scale in three or four years.


Good news.  Obviously the main barrier to widespread solar panel adoption is the high price.  If these researchers can maintain the efficiency while significantly cutting costs, we could start to see solar panels becoming much more commonplace.

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post #2 of 11
7/8/09 at 11:11pm
 Something needed urgently for both solar and wind is a government approved third party testing/rating agency.

At present most parties select test criteria which suit them. There are no standard tests or protocols.

For the layman who does not want to or does not have the time to do many hours of research it is impossible to determine what really works. Even spending the time I get more confused than enlightened all too often.

There is such a thing for solar hot water - the SRCC. I really appreciate the organization.
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post #3 of 11
7/9/09 at 12:10pm

Now, how great would it be if they could bring down the price AND increase the efficiency?    Maybe a pipe dream, I know but there's always gotta be hope.


Agreed, Russ.  SRCC is a great organization.  Having an exisitng body set up to test and set standards is very important.

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post #4 of 11
7/11/09 at 7:10am
The high efficency of solar panel is good news for solar power product. In my experience, the current silicon panel is not fully used in product.For example, the size of 25x25CM silicon should supply 6W power, but some vendor produce the solar PV panel with only 3W or even small power. Cost down and more profit are their target.
 
edited for violation of commercial policy - Russ
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post #5 of 11
7/15/09 at 1:18pm
There are many reasons why silicon is so expensive. The main reason is there are too many people in the middle. Silicon ingots are sold twice before the solar panel company gets the raw material. Then the solar panel is sold to distributors, then to dealers and finally to the end-user. Too many people in the profit bucket. The end user pays over $3.00 a watt for silicon (sand mica) But during the process the low grad silicon or dirty silicon is sold to solar cell companies. They need the dirty type over the chip type of silicon to absorb light. The clean silicon refracts light too much. This is the silicon story. Now for CIG type solar sell. These cells cost a lot less to produce but the companies that produce these type of cells match the prices of silicon solar cells. These are big profit companies. Ribbon Cells or printed on a mylar substrate or glass. These are the cheepest sells availabe. The problem with ribbon cells is size. These are huge, with very little power. There is a way to increase any solar cell's output of watts by using concentrators. The problem is the life of the solar cell is reduced and the performace of a cell drops off a lot due to heat. The only solution is to go back to CIG cells that don't weaken over time. Use concentrators and use a air gap between the solar cell and concentrator. Most solar panels are tilted so that the hot air between the concentrater and the cells on the panel can rise. The biggest problem is the data on the back of a solar cell is tested at the lab end. Not out in the field. You think you have 200 watt solar panels but you can only get 180 watts. This data is not wrong but in the real world it is. There are solar cells that are 41% or 410 watts per meter at 68 degrees F. in full sun. At MIT they have a solar cell that is 57%. But these are lab conditions only, again not the real world. It is like the EPA Milage Sticker on new cars. None of these window car stickers are correct. These are lab results only.
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post #6 of 11
7/18/09 at 10:34am
And part of the power "sticker shock" has to do with power conversion. Running PV DC straight into batteries always leaves you a bit off ideal point on the panel's output curve. Try to get it right using maximum power point tracking devices and you lose a bit in the volts-to-amps switching of the unit.
 
My favorite idea, which I think was once briefly manufactured somewhere, was a concentrator panel with water cooled cells. The efficiency stayed up due to improved cooling, it used less silicon, and the hot water was used for domestic supply. It probably died an early death due to water leakage, complicated manufacturing, or an overly-optimistic warranty.

So when are we going to see Nanosolar.com's paint-on, doubly-efficient, long-lasting PV at $1.00/watt?
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post #7 of 11
7/18/09 at 11:32am
 The solar paint? Probably not too soon. The technology is still out there somewhere.

The water cooled concentrator - there are several out there -   www.arontis.com   - for one and spogy for another. 
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post #8 of 11
7/21/09 at 8:00am
Nanosolar seemed to be doing lots of production in Germany but not in the States. Last year I talked to a physicist who is an advisor to Nanosolar and he told me not to hold my breath, indicating that the physics was sound but the production was having some glitches. he was more proud of one of his students acheiving 42% efficiency for the panels on one of the Mars landers.
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post #9 of 11
7/22/09 at 4:53pm
Russ, On solar photovoltaic there are standards. The efficency of a solar panel is determined by 1,000 watts a square meter. One sun and 68 degrees F. From these conditions they can read the volts and AMPS these two readings; when multiplied are watts. These are the conditons for testing the solar photovoltaic standards. The major problem that I have always complained about is this is not the real world. Silicon solar panels loose their power over time. CIG solar panels are just the other way around. They are rated after a 2-3 month test. For some reason when you first install CIG solar panels they put out about 20% more electric power than what is printed on the back of the solar panel. These test conditions are always the same. Oh by the way the one sun issue; is at sea level. I guess in Colorado it would be 1.5 suns.  
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post #10 of 11
7/22/09 at 10:26pm
 Right Jim.

One problem with the standards and the way they are represented is that some parties try to play up the initial output rather than the degraded (approx 20% as you noted) output. It makes their product look better.

Anytime a company misrepresents their panels in this manner it makes me wonder about their overall honesty, quality control etc.

For the actual insolation of any area quite possibly there is someone around with a weather monitor that has a solar receptor integrated into it. My Davis station does and I log it daily but only started back in May - need a bit more time. For May, June and July, here in Izmir, we see just over 7 kw/m2/day. There are decent maps on the net also for this purpose. NASA provides data for most any plave in the world.

I have done a lot more looking at solar water heating panels than I have at solar PV. At present (all summer) our hot water temp is 90 degrees C with the power turned off to the heater tank electric backup. I expect to turn the back up power on again in November as is required during stormy/cloudy periods.
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post #11 of 11
7/23/09 at 1:51pm
Quote:
Originally Posted by jim386 View Post

These are the conditons for testing the solar photovoltaic standards. The major problem that I have always complained about is this is not the real world. Silicon solar panels loose their power over time. CIG solar panels are just the other way around. They are rated after a 2-3 month test. For some reason when you first install CIG solar panels they put out about 20% more electric power than what is printed on the back of the solar panel.

 

CIG are a type of thin film cell (like amorphous silicon types) and both should be quoted by the manufacturer after their period of initial Staebler-Wronski degradation (a few months).  After that they degrade at the same rate as standard silicon wafer cells (down another 20% in 20-25 years).

I have Sharp polycrystalline panels and these do put out their rated power of at least 170W in daily maxima bright sunshine in SE UK (so at about 52 degrees North).  I have them mounted on angled frames on a flat roof so they get lots of cooling air that helps.  Panels that are mounted on a pitched roof get hotter due to poor ventilation of the rear face and heat soak into the roof tiles so they output less.  In partially cloudy weather they can output up to 118% of their name plate power (I saw this today) due to concentration of rays diffracted by the cloud boundary that makes the light temporarily stronger than normal.  Typically, I see at least 100% to 105% of the name plate power on a clear blue-sky day (no haze).

This is real Amps measured into the 24V battery bank after going through a Morningstar MPPT charge controller.  The panels operate at 46.4V (two in series) and the MPPT controller DC-DC converts this to the battery voltage (24-29V).  So, much less power is wasted in the solar DC cables and the panels operate at their ideal maximum power point.  The real power of the panels is about 3% more than that as some energy is lost in the DC-DC converter (it gets warm when running at 14A output but is a fanless design so doesn't waste much).

I've discovered that it does pay to buy quality panels.  I started out buying cheap Chinese amorphous panels and they lied about the rated power, claiming they were 12Wp and 15Wp.  Both types after about 6 months use degraded to about 64% of their name plate power in the same location and lighting conditions as the Sharp panels. The amorphous ones are on a second controller because they operate at 35V in pairs.

Rather than buy more new panels, I now buy second hand good brand ones (Sharp, Kyocera, BP) from eBay and they are cheaper than the new unbranded cheap Chinese mono ones but they perform at very close to or above rated power, all have 20-25 year power warranties, are rated at +-5% or +10%-5% tolerance, and have superior build quality that looks like it will actually stand being outdoors for 25 years.

My best bargains have been a pair of Sharp 80Wp panels for £455 (£2.84/Wp or $4.55/Wp) and an unused BP 160Wp 24V panel at £375 (£2.34/Wp or $3.75/Wp). The BP one was bought by someone who then left it in a storeroom and forgot about it until he found it when moving house! 

The absolute cheapest panel I've bought was a used poor quality unbranded (cheap Chinese) 40W-ish monocrystalline panel. I've never seen it put out more than 34W but it looks identical to panels that are rated at 40-43W.  That only cost me £67 (£1.97/Wp or $3.15/Wp) but it only does light duty as a spare 12V battery charger because I need 24V PV strings and this one is an odd-one that I picked up. Its frame is a bit weak (thin aluminium) and it doesn't look like it would be waterproof for very long (the cells are spot glued on some kind of board with a glass plate overlaid - not permanent skin encapsulation (like the quality brands I bought). Its voltage is a bit on the low side too so it would be hard to find a partner that didn't suffer mis-match losses... It might have enough power to run a tracker for the 340Wp Sharp array though... :)

As for my poor amorphous panels... they are being phased out and sold off.  They take up too much space for too little power output.
 
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