Focus, focus: Sunrgi’s concentrated photovoltaic module consists of lenses that focus sunlight on a high-efficiency solar cell, and a special heat sink designed to dissipate the extreme heat produced by such an intense concentration of the sun’s rays.
Sunrgi
Sunrgi claims that its concentrated photovoltaic system outshines the competition.
A Hollywood-based solar startup says that it will soon be able to produce electricity from the sun at costs that are competitive with fossil-fuel generation. The key is the company's dramatic improvement in the performance of concentrated photovoltaic technology.
Sunrgi, which emerged out of stealth mode last week, has created a concentrated photovoltaic system that uses a lens to focus sunlight up to 2,000 times onto tiny solar cells that can convert 37.5 percent of the sun's energy into electricity. Stronger concentrations of sunlight allow engineers to use much smaller solar cells, making it more economical to use higher-efficiency--but higher-cost--cells. Sunrgi, for example, will use cells based on gallium arsenside and germanium substrates.
Paul Sidlo, one of seven founding partners of Sunrgi, says that the system uses four times less photovoltaic material than other approaches, which typically aim for 500 times sun concentration. This includes systems being developed by California rivals SolFocus and Soliant Energy.
"We've miniaturized everything," Sidlo says. "What this leads to is reduced cost, and the big breakthrough here is all about lower cost." The company has also designed its system to be produced on slightly modified computer assembly lines, enabling further savings through high-volume production. The higher efficiency also means that a solar park built with Sunrgi's modules could use one-sixteenth of the space needed with conventional thin-film solar cells, adds Sidlo. The result is lower real-estate costs for developers.
Sunrgi estimates that its system will be capable of producing electricity at a wholesale cost of five cents per kilowatt-hour. Prototypes have been built and tested both in the laboratory and in the field, and the company expects to start commercial production in 12 to 15 months. "It's quite an aggressive claim," says Daniel Friedman, a solar-energy researcher at the U.S. National Renewable Energy Laboratory (NREL). He says that most others in the space are still working toward seven or eight cents per kilowatt-hour. "I can't say Sunrgi won't achieve what it's claiming, but right now, it's just on paper, and costs like that are only going to be a reality at the large manufacturing level," he says. "Even then, the five-cent figure sounds really optimistic."
Arguably the biggest breakthrough for Sunrgi is in the area of heat management, which is essential to any concentrated photovoltaic system. The intense heat created by concentrating the sun so much can reduce both the efficiency and the life of the solar cell. At 2,000 times sun concentration, temperatures can exceed 1800 °C--similar to the heat from an acetylene torch, and hot enough to melt the solar cell.
Cells in such systems are usually cooled through a combination of heat conduction, air or liquid convection, and radiation; the goal is to remove as much of the heat as quickly as possible, says Sunrgi partner KRS Murthy, who has been labeled the "thermal wizard" by his colleagues. "At each stage of conduction, convection, and radiation, we've made an improvement over what others have done," he says.
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"The higher efficiency also means that a solar park built with Sunrgi's modules could use one-sixteenth of the space needed with conventional thin-film solar cells, adds Sidlo. The result is lower real-estate costs for developers."
How does this work? They still need to initially collect the sunlight from the same area that the thin-films do, even though they're concentrating it on a smaller photovoltaic area. So how does this save land area?
Since the efficiency is higher, the cells only have to capture some fraction of the light that a typical cell would. Even if they are 2x more efficient, this is still a substantial reduction in surface area.
The article makes only limited sense.
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It is unlikely that concentrating the sunlight would increase the efficiency of the solar cells, i.e., the percentage of the light that would be converted to electricity. Thus, light concentration WOULD NOT reduce the amount of land necessary to generate a given amount of power. Assuming that the optical system were 100% efficient, the land area required would be exactly the same as if there were no concentration whatever. If concentration actually did boost conversion efficiency, the land area required would be reduced only by the amount that the efficiency is increased. Reducing the land area required by the stated amount would probably require solar cells with an efficiency exceeding 100%. It may be that the author is unaware that efficiency cannot exceed 100%.
<P>
Light concentration could conceivably reduce costs by reducing the mass of solar cells required, but the article does not cover that possibly. It is only a possibility, since any savings in the cost of the solar cells could be offset (or more than offset) by the required optical system and cooling system.
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It appears to me that the author of the article has only limited technical competence. I suggest that it be made impossible to get a degree in journalism without having studied physics at the college level for at least one year.
Nope, wrong.
The efficiency (percentage usable power out/power in) of a solar cell increases when the light intensity increases.
ie if you had a 1 square metre ordinary flat panel, you would get about 150 watts (15% efficiency).
If you had a 1 square metre concentrating array (at 40% effiecient), you would get
1) 400 watts out (for the same power in)
2) at the same time, you would use a smaller amount of silicon
So if you concentrate 500x, you would use 1/500 of the silicon cf normal flat panel, AND you would get much higher output for the same solar input, AND you could use the waste heat in a heat engine to generate even more power.
Interesting. I'd have thought that that sort of concentration would simply lead to a greater proportion of waste heat. But then I'm not an engineering person...
Sure, but the 16x less land claim is still rubbish. Even if the efficiency of the thinfilm is just 5% and the concentrator 50% (impossible with state of the art technology, even if the concentrator optics are 100% efficient, which is also quite impossible) then it's just 10x less land. In reality, it's not that good, because a dual axis tracker needs more land due to greater spacing between the modules to avoid shading (compared to flat plate ie the thinfilm counterpart).
No....It's 10x10x less land (Area of a square remember is base TIMES height)
We're talking 2 dimensions, not one.
And the comparison was to thin film, i believe. Most thin film solutions marketed today have a little under 10% efficiency. This product is claiming 37.5% efficiency. 9% x 4 = 36%....therefore, a claim of 4x efficiency is justified, with the area being, wait for it, 4^2 = 16 times less land for the same energy produced.
'sokay, i'm here for ya when you need a girl to do your math.
I'm intrigued by the amount of concentrated heat that this system can create and would like to see ways this technology can be harnessed to create solar driven heat pump. A few smaller units sitting on a rooftop could use part of the electricity generated to pump the heat from the solar collector into the house. While having cheaper electricity would be a plus, being able to not spend thousands on home heating oil (currently at $4.00 per gallon in New England) would be amazing and much cleaner.
Well, this is the future of solar (steam turbines, with steam created from concentrated solar heat), I'm quite sure. One thing that hasn't been mentioned cost-wise is the cost of disposing of stuff like galium compounds, which are highly toxic, compared to the steam turbines which are not toxic. There are some pretty big installations of this sort (http://en.wikipedia.org/wiki/Solar_Energy_Generating_Systems). Here in South Africa, we could easily produce our entire electricty supply from CSP! I'm sure that this is the renewable energy that will ultimately be rolled out on the largest scale! And I'm sure that if everyone in the world used solar geysers, it would make a huge difference.
"Sidlo says that Sunrgi will initially be targeting utility-scale developments and is in talks with strategic partners, including manufacturers." Are utility-scale developments needed just because of regulated price controls to the end-customer?
Sunrgi solar technology on many roofs seems to be the logical case for distributed solar generation that statistically would have a high net input into a smart grid that transport electricity in both ways. Do non utility-scale developments need the elimination of price controls to the end-customer to be viable? Most energy will be produced where needed without transportation losses.
The price controls debate seems to be overdue.
Assume the price control debate ends enabling customer's choice. Sunrgi might later on be targeting off-the grid developments. To understand the opportunities beyond Off-the-Grid Housing, please take a look at what I wrote under Everyone for Himself Solution: ------ Off-the-grid housing is an everyone for himself extreme alternative solution, that is fed with uncertain generation, with on-the-grid housing being the other extreme. ------ The optimal energy policy is one that separates the grid from the commercial business transaction. The grid is develop as a controlled market to service the whole at least costs and to enable a vibrant open market. ------ Today's utilities monopoly retail business model of winning rate cases to the regulator shift to innovative business models that are open to competiton, in order to coordinate customers and generators investments and operation costs, resulting in large saving that result in maximum social welfare. ------ For details, please hit the javs hyperlink above to read about the EWPC market architecture and paradigm that makes the grid a two way street. ------ Please see also mikeforsyth comment under Re: Everyone for Himself Solution and my response to him.
Just another story that will fall off the map
Every few weeks or so we hear about some new company that has come out of the closet with a new technology that will allow us to capture the suns energy more efficiently what makes this one any different. frankly im tired of hearing about all this and not seeing results i understand it takes time but honestly wtf?
Re: Just another story that will fall off the map
It takes many years to take a functioning R&D project to mass production. The bulk of the major new solar energy announcements happened in the last 3 years. Give it time -- it will come. Until then, do your best to vote for political candidates that are passionate about renewable energy and will kill the Oil and Coal company subsidies and invest in Solar, Wind, Hydro, Tide, etc
The second graphic looks a bit deceiving.
2,000 Suns obviously takes 2 axis tracking.
Rather than the simpler single axis elevation tracking that "trough" systems use.
Those entire linear banks rotating to track the East to West movement of the Sun?
You could imagine a second mechanism that translates the target solar cells laterally along the axis of the panel array. You would have to live with abberation and hence reduced efficiency off-axis. Or each cell could individually rotate in a louver arrangement.
There's no way that can be done with sufficient accuracy under 2000x concentration.
A lot of red flags on these claims. The company appears rather incompetent when judged by their website and their claims, many of which are simply impossible by physics. If I were an investor, I'd hold on to my wallet, for now at least.
It's possible to tilt a unit from behind and also from the side. The degree of tilt would be less from the side, but it would still help to track the Sun over a portion of the day.
As far as the 1/16 land use claim, the factors that contribute to it would include:
1. Tracking versus non-tracking
2. 37.5% eff versus about 20%
3. Concentration of sunlight versus none
4. Heat removal versus none
5. Additional layers in multijunction cells that permit more light into the cell and keep it there longer
It's not as simple as saying that the same area has the same sunlight.
This just shows how far solar has to go economically. If this Rube Goldberg device can be cost-competitive, then there's serious room for entrepreneurs to make a killing. Solar energy is so diffuse that in order to break even with fossil the equipment needs to be really really low cost - like football fields of area for a few thousand dollars. At best this is a stepping stone soon to be leapfrogged by one of the many "print PV like newsprint" schemes. At worst someone has missed a decimal point or two in their calculations. The opportunity, however, is that the global energy biz is a $4,000 Billion industry. That's a $4 with a capital T. Every year, year after year.
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Gaetano Marano
246 Comments
>>> "competitive with fossil-fuel generation" yes, but, at WHICH oil price? >>>
.
"competitive with fossil-fuel generation"
yes, but, at WHICH oil price?
- past $20-30 per barrel?
- today's $120 per barrel?
- tomorrow's $200+ per barrel?
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ghostNASA.com
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Guest (cgs)
Re: >>> "competitive with fossil-fuel generation" yes, but, at WHICH oil price? >>>
Mmmm... I suspect there are some hidden costs.
Fresnel lenses.
Special dissipation fluid.
And some energy wasted in the fluid circulation.
Let's wait and see...
Reply
asdar
73 Comments
Re: >>> "competitive with fossil-fuel generation" yes, but, at WHICH oil price? >>>
They're competing with Coal, the cost of coal is about 5 cents.
Reply
doug_houseman
1 Comment
Re: >>> "competitive with fossil-fuel generation" yes, but, at WHICH oil price? >>>
The price of oil does not matter in the world of electricity, coal and natural gas rule.
More important, if they are really getting 1800 degrees C as waste heat, they have a perfect opportunity to use salt as a heat storage mechanism and provide thermal generation of electricity at night.
This would further lower the average cost per KWh, if they can build it for a reasonable price.
As the article states and I agree, it is all on paper. NanoSolar has claimed that they will over installed thin film for a dollar a watt, again on paper. That would mean that with each installed watt producing 1KW per year (non-optimal location average - in the desert it would be closer to 2.5KWH per year) and a 20 year life that they would be in a similar range for power.
Lets see if either company is willing to sign a 20 year deal at that price for solar power. If they are, I am willing to sign up.
What say - a locked in price for 20 years at 5 cents a KWH (not including transmission and distribution, taxes, license, fees, etc).
Sounds good to me.
Doug
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