|
Renesola - Chinese Solar Panel/Silicon Recycling
mbadfvn05 - Wed, 27 Dec 06 :
superrod & randsys
Re: your posts on 23rd Dec/ No.s 18133 & 18134
and this link posted by superrod:
BEWARE OF SPIN - all is not as it seems with the Boeing's claim of 40.7% energy conversion ratio
The article in the above link is basically Hype and spin to justify the millions of dollars of subsidies/grants the US Government gives Boeing to research PV solar energy.
So it leaves out one essential fact namely: that to achieve the 40.7 efficiency ratio claimed in a lab, the light source used was over 240 times as strong as sunlight
This article in earthtimes.org reveals the essential fact not included in the above article
Photovoltaic cells turn regular sunlight into electricity using a chemical reaction. Concentrator PV cells convert stronger light; the models now on the market concentrate the light either with external, curved mirrors, or with special magnifying glass overlays called Frisell panels.
However, for testing purposes, Boeing uses special strong lights that have a concentration equal to 244 suns. This way, results can be easily replicated, Dave Garlick, a Boeing spokesman, told UPI.
Conventional solar cells, whose main ingredient is multicrystalline silicon, have one layer of photovoltaic material, but the solar cell in question is a multijunction cell -- it has three layers of photovoltaic material, one on top of the other, Jeffrey A. Mazer, a photovoltaics engineer at the U.S. Department of Energy, told UPI.
See link :
Basically concentrator systems are a bit like using a magnifying glass to concentrate sunlight into a small spot – most of us did this when we were kids!
Think about it – light 240 times that of the sun is very, very hot. Boeing solar cell needs this incredible amount of light and heat, because it is so inefficient!
A conventional polysilicon cell has only one layer of polysilicon (the semi-conductor material) with electrical contacts on the front and back. The Boeing system uses three layers of electrical contacts sandwiched between several layers of a new type of semiconductor, thought to be, zinc-manganese-tellurium, combined with a few atoms of oxygen (but other materials such as germanium have also been used in multi layer systems).
The claim that this is more efficient than conventional polysilicon solar cells is based on the claim that Boeing’s multi- layer PV cell converts a wider spectrum of the sunlight into electricity i.e. also heat. However, in ordinary sunlight the Boeing cell produces virtually no electricity. To harvest solar energy the Boeing PV cell sunlight has to be boosted using reflectors or magnifying glass such as Frizzel panels.
In fact Boeing’s hyped up claim is not new technology. They and others have been working on this multi-layer PV cell system for more than 25 years, and are still a long way from bringing it into commercial production.
From the above same earthtimes article
“However, Mazer said, passing the 40 percent mark isn't such big news. Efficiency has been steadily increasing ... 40 percent efficiency is not a gigantic change qualitatively or quantitatively, he said. Cells boasting 43 percent or 44 percent efficiency were always on the way, he said.
He said that this kind of cell was first developed by the NREL in the late 1980s and early 1990s, and that the laboratory still holds the original patents for this type of cell, which is known as a multijunction III-V monolithic stack.But even if breaking the threshold isn't an earth-shattering development, it puts the holy grail of solar energy -- cost effectiveness -- in reach, the Department of Energy's team leader for photovoltaic research and development, Richard J. King, told UPI.”
In practical terms and commercial applications the crucial metric is the area and cost of the entire system including the reflector/magnifying concentrators compared to conventional and thin filmed systems.
Both concentrator and thin filmed systems compare very badly with conventional polysilicon systems because for any given W rating, concentrator and thin filmed systems need a much larger area (2 to 4 times as much in the case of thin filmed and even more in concentrator systems) than conventional polysilicon wafer PV systems.
This difference is absolutely crucial in practice, because in urban installations on or around domestic, office and commercial buildings thin filmed and concentrator systems produce far less electricity for any given area compared to conventional polysilicon wafer based systems. Because of this crucial difference thin filmed systems (and the same probably applies to most if not all concentrator systems) cannot even produce enough electricity to meets the needs of the building!
I have previously posted about the comparison between thin filmed and conventional PV systems which vernit has archived on his excellent thread – see post No. 80
Conventional polysilicon wafer PV systems presently have over 90% of the PV solar market – with the remaining less than 10% split amongst various thin filmed and concentrator systems.
In the above post I conclude/predict that for the foreseeable future conventional polysilcon wafer systems will capture most of the urban market on or around domestic, commercial and office buildings while thin filmed and concentrator systems will be located in large out of town solar power plants.
Superrod’s article also makes a mistake saying that conventional polysilicon based PV systems only achieve 12% to 18% efficiency.
In fact PV cells based on Multicrysteline wafers reach up to around 15% and systems based on Monocrystaline wafers have reached 22%.
The highest efficiency commercially available PV cells is based on Monocrystaline wafers by Sunpower (not one of SOLA’s customers – yet…LOL) Their latest Gen 2 solar cells achieve 22% efficiency. See link:
The next most efficient PV cells I know of are by Suntech with 18% also based on Mono wafers (they are a SOLA customer). They have plans to reach 20% and perhaps more with the help of the University of NSW.
The other crucial thing one has to look at is the overall cost of a PV system, not just the cost of the cells themselves i.e. the cost of assembling panels, making modules, transporting and installing them. Makers of thin film and concentrator systems tend to skip over this and do not give details which allows a proper comparison.
Thin filmed systems makers usually just highlight the low cost of making the actual cells but leave out the other costs. With efficiencies of 5% to 9% (and Nonotechnology claiming 12% in lab tests) they require 2 to 4 times the areas required for a similar power rating and therefore 2 to 4 times larger panels, modules and larger installations etc.
Concentrator systems, tend to highlight the higher efficiency they may achieve. But this often just in lab conditions (like Boeing’s claims) but do not include the costs of the large and expensive reflectors and magnifiers they need and much larger system areas and installation costs.
Just how important total cost efficiency per area and output is highlighted by market performance arising from differences within conventional wafer PV systems in California where comparisons can be made. Sunpower, with its earlier generation 20% conversion efficiency PV cell systems, has taken massive market share from its competitors, who have conversion efficiencies of around 15%. This is from Sunpower’s Q3 ’06 results:
“Increased market share: Over the past four quarters SunPower increased by a factor of seven its share of the California residential solar retrofit market as measured by kilowatts installed. During the third quarter, as reported by the California Energy Commission, SunPower captured a 14% share of this market.“
See link:
There are other crucial advantages which conventional polysilicon wafer PV systems enjoy. This is tried, tested and reliable technology with installation history going back some 40 years, with little or no decline rates from initial conversion efficiencies.
Thin filmed and concentrators systems are mostly experimental, lab tested ones with almost no track record of reliability. There are large hurdles to transform lab based systems to commercially produced and installed systems and this process normally take many years.
Additionally, many if not most, perhaps all, thin filmed and contractor systems show efficiency decline rates from the initial rating. How fast and by how much such efficiencies will decline over a period of 20, 30 or 40 years is unknown.
So even the most promising thin filmed and concentrator systems entail huge commercial risks, not just for the backers financing the companies producing them, but also for their customers, if they can be persuaded to spend billions setting up a large out of town PV plant (or solar farm as they are often called). The customers then have to cross their fingers and wait years to see if these systems prove to be reliable!
Meanwhile conventional PV cells, based on polysilicon wafers, are not standing still. Costs per W were steadily decreasing until the shortage of polysilicon raised costs for the raw material. The PV polysilicon industry is following Moore’s law in the semi-conductor industry – but at a slower pace.
Sunpower have a road map to reach the Holy Grail of grid cost parity by 2012. However, this target may be postponed for while because the shortage of polysilicon is now generally recognised not to end in 2008 but persist to 2010 or longer. See my earlier post:
Sunpower are the technology leaders with propriety patents safeguarding their lead in PV cell polysilicon wafer based systems and will continue to expand their market share because of this. However other PV cell polysilicon wafer companies are following them down the path towards grid cost parity.
As the Holy Grail of grid cost parity is reached the PV market expansion will accelerate, opening up the entire $1,000 billion market a year generating business to the PV solar industry!
I have carried out quite a bit of research into the entire PV solar market. I will continue to do so and I welcome any contributions from other posters. I have so far found nothing which alters my firm conviction:
* that polysilicon wafer based PV cells will remain the dominant technology for some time;
* that SOLA are in the sweet spot with accelerating demand for their products from a rapidly expanding PV cell polysilicon industry
* that there will probably continue to be a shortage of polysilicon to 2010 and probably beyond
Renesola Stock Charts : |
| Renesola Historic Stock Chart | Renesola Intraday Stock Chart |
 |  |
|
|
|
|
Renesola stock quotes
Renesola stock charts
Follow this thread
