Further reflection: This new solar cell is extremely efficient but can be made cheaply, thanks to a new technique for affixing mirrors to silicon.
Suniva
New materials for high-performance cells could make solar power affordable.
A cheap new way to attach mirrors to silicon yields very efficient solar cells that don't cost much to manufacture. The technique could lead to solar panels that produce electricity for the average price of electricity in the United States.
Suniva, a startup based in Atlanta, has made solar cells that convert about 20 percent of the energy in the sunlight that falls on them into electricity. That's up from 17 percent for its previous solar cells and close to the efficiency of the best solar cells on the market. But unlike other high-efficiency silicon solar cells, says Ajeet Rohatgi, the company's founder and chief technology officer, Suniva's are made using low-cost methods. One such method is screen printing, a relatively cheap process much like the silk-screen process used to print T-shirts.
So far, the high cost of solar cells has limited them to a marginal role in power production, accounting for less than 1 percent of electricity worldwide. Rohatgi calculates that the company's low-cost manufacturing techniques will make solar power competitive with conventional sources, producing electricity for about 8 to 10 cents per kilowatt-hour--the average cost of electricity in the United States and far less than prices in many markets.
Suniva's cells are efficient largely because they can trap light, keeping photons inside the active material of the solar cell until their energy can be used to free electrons and generate an electrical current. The basic concept of trapping light is not new. It relies on texturing the front surface of the layer of silicon that forms the active material of the solar cell. The texturing creates facets that redirect incoming light, refracting it so that, instead of passing directly through the silicon, it travels along the length of the silicon layer. The photons thus stay in the material longer and have a better chance of being absorbed by atoms in the material. When that happens, the energy in the photons can free electrons that are used to generate current.
Light trapping can be enhanced by pairing the textured surface with a reflective layer at the back of the silicon layer. The mirror keeps the light in the solar cell still longer, further increasing the number of freed electrons. As a consequence, the silicon can be half its ordinary thickness while absorbing the same amount of light. Using less of an expensive material reduces costs directly. But it also allows solar-cell makers to make do with cheaper, less pure forms of silicon. In a conventional solar cell, which can have a silicon layer 200 micrometers thick, impurities within the material can easily trap electrons before they reach the surface and escape to generate a current. In a layer of silicon just 100 micrometers thick, however, the electrons have a shorter distance to travel, so they're less likely to encounter an impurity before they escape. Lower-grade silicon is much cheaper and easier to make than the highly refined silicon ordinarily used in solar cells.
Thin but efficient solar cells use one-tenth the silicon of conventional cells.
The silicon shortage that has kept solar electricity expensive is ending.
Gaetano,
I would really like to know where you are getting those numbers. The last study I have seen said that it would cost 500billion (not trillion) to supply the USA with energy through solar. even if you are being conservative and say that america ONLY consumes 10% of the worlds energy then the cost for the global energy demand would be in the 5 trillion and not 15.(The true meassure of us consumption lies probably closer to 20 - 30%)
Furthermore, if you get all your energy from these hideous wind farms that would have consequences as well. according to studies done by NOAA if all energy were to be gathered by wind turbines we would slow down the earths atmospheric currents (ie jet stream, trade winds, etcetera) This slowing down of the global wind currents would result in a heating of the tropics and a cooling of the temperate zones.
Also, solar has almost no moving parts and hence the cost is pretty much only upfront. Wind turbines are complex machines that need constant upkeep i.e money
I've based my calculations on today's world electric energy needs and today's solar panels prices
in this table... https://www.cia.gov/library/publications/the-world-factbook/rankorder/2038rank.html ...you can find the 2005's electric energy production figures, that are:
2005 World: 18,580,000,000,000 kWh
2005 USA: 4,062,000,000,000 kWh
my $15 trillions evaluation is to produce (about) twice today's electric energy (in future) with more efficient and less costly solar panels
if the USA electric energy share will remain the same, only $3 trillions would be needed to power it with earth-based solar cells ...or $650-1600 trillions with space-based solar power plants.
Of course, at that scale, the production costs alone would drop significantly. Then factor in that, with such a market, the R&D into solar would multiply vastly, resulting in a sharp gain in the rate of efficiency increase.
Solar power, in contrast to wind generation, is a non-intrusive, clean, silent form of energy generation that requires virtually no maintenance.
The solar energy at the Earth's surface has an average power of 89,000 Terawatt (1 TW = 1012 Watt). In comparison: the total average energy flux of all the wind available on the planet is 370 TW and the average global power consumption 15 TW.
In addition to being abundant, solar energy is reliable and has an outstanding energy payback.
With today's technology, a silicon photovoltaic cell produces 20 times the energy it takes to make the module. [1]
[1] 1366 Technologies
.
the main problem of solar arrays is not its efficiency but its PRICE
if and when its price will be (really) competitive, they'll be (surely) used for large scale power plants
.
Is this a Disrupive Technology?
Mr. Kevin Bulls,
There are many locations in the world at the very large market of the Bottom of the Pyramid (BoP), in which electricity prices are above 20USc/kWh. Rotating blackouts are a key feature at the BoP, because of the price controls business model rations electricity at the circuit level. Consider the EWPC article Electricity for the Digital Era, Part 2, whose summary states “It is very clear that we need electricity for the digital era, where retail competition is about business model innovations that will develop the resources of the demand side and enable demand elasticity. To transform local utilities from regulation or deregulation to EWPC we need to enable as soon as possible a transition to a complete and fully functional market on the digital era, under an EWPC Energy Policy Act,” can efficient, cheap solar cells be classified as a text book example of a disruptive technology once demand side price controls are eliminated in those unserved BoP markets.
Regards,
José Antonio
Global warming? Global cooling? Global climate difference?
I'm usually a numbers guy, but I admit I don't have a clue about the numbers here. I'm way out of my area of expertise, so this must be treated as non-quantitative speculation.
What are the prospects for global climate change if we adopt large-scale solar electric power? (Or, for that matter, wind power as has been suggested in this discussion.)
Consider: One fossil-fueled power plant would not make a measurable change in the climate. Nor would ten. But thousands do, especially if you add in our transport systems as well as electric power. Enough fossil fuel for the world's energy needs makes a very discernable impact.
So what about solar? Reading between the lines of the article, a 25% efficient solar cell would be competitive with other forms of generation. Let's use that number. At 25% efficiency, how much of the southwest desert would have to be coated with solar cells to supply the country's electric (and transportation, assuming a transition to hybrid/electric vehicles) needs? I'm assuming the southwest desert and electric transmission elsewhere, because that seems to be the highest-yield strategy for the continental US.
IF 0.1%, then I won't worry.
IF 50%, then I have to ask, "What does it do to the climate -- local and global -- if 1/8 of the sunlight on the desert (25% efficiency times 50% coverage) is neither reflected nor absorbed there and turned into heat? If, rather, it is transported elsewhere on the planet and converted to heat, light, or motion at the point of consumption?"
The same could be asked about wind farms, if there were enough of them to supply all our power.
Does anybody have the numbers on coverage? I'm sure nobody has the answers [yet] on climate effects, though I sure hope the question is asked before we actually get there.
DaveT
Re: Global warming? Global cooling? Global climate difference?
I don't think your heat-transfer concerns would be a big issue. Using any other form of energy is already releasing heat into areas where it wouldn't be otherwise, so the real issue would be a sudden cooling of the area it's being absorbed from.
It's possible that the reflection of light from the desert is already cooling the area to the same degree that absorbing it into photovoltaics would be.
And of course any resultant heating would be way less than the green-house effect from burning fossil fuels.
Re: Global warming? Global cooling? Global climate difference?
While I remember there was a Scientific American article about 6 months ago with the U.S. specific math, I've read that approximately 2% of the Sahara desert (9 million+ square km) would provide more than enough energy to supply the entire world. Now obviously that wouldn't work from a logistics point of view, but in terms of round numbers, that's what you're looking at.
Who knows, solar farms might even provide beneficial microclimates, creating shade and enabling new ecosystems to thrive in the desert.
Re: Global warming? Global cooling? Global climate difference?
DaveT - these are great questions. Luckily, a lot of people have considered them. One potential, very rough estimate, is covered in my blog post here, extrapolating based on the 550MW Topaz solar farm planned by PG&E in California. My conclusion was that we would need about 800 Topaz-sized plants, total cost about $1 trillion, to meet the U.S. electricity demand. And it would require about 8,000 square miles of sunny land.
My goal with this estimate was to get something simple and easy to understand - there are many much more detailed analyses out there.
Hope this helps.
Nils
Re: Global warming? Global cooling? Global climate difference?
I'd like to make a disclaimer and state that this comment is based on all assumption. corrections are welcome and encouraged
assumptions:
1. 90% of solar light is absorbed by solar cell 10 % reflected back into space
2. of that 90%, with these cells 20% is converted into electricity the remaining 80% becomes heat in the solar cell.
3. 90% of the electricity ends up as heat. with a remaining 10% as electronic emissions or street light that makes it out to space
4. desert sand may have a much higher reflectivity, could it be about 70%
if the assumptions are anywhere close, maybe 88% of light that hits a solar cell heats the earth in one form or another. Where as if light falls on a desert floor may absorb 30% of it absorbed and radiated as heat.
It might be worth considering areas that have lower reflectivity to start with before transforming area's with solar cells.
It is also noteworthy to mention heating the earth is not the same as keeping heat in.
I'm no scientist, nor much of a business man. But I wonder why everyone seems to think only of large scale solar production. Is the model of central distribution so ingrained in us that the idea of individual energy self reliance has been washed out of our brains? Is the idea to keep energy in the hands of the greedy corporate world?
To me it seems the promise of such technologies are feasible on a much more personal scale and could get many people off the "grid". Especially in times when that grid seems so vulnerable to natural and man made disasters. Or don't we have the right cut that hallowed cord? Or build new communities without expensive power lines? Empower the people!
Re: Small scale individual solar
Great question. I think the reality is that there will be a combination of utility-level and distributed energy, and of different types - solar PV, solar thermal (heat your own hot water for showers), wind, etc.
There's a very interesting set of Department Of Energy reports, including one (PDF) on the market opportunities for grid-tied distributed solar PV. It figures out, state by state, how much roof surface is available, how attractive the incentives and infrastructure are (e.g., is there net metering?) and uses some simple algorithms to come up with an expected market penetration for solar PV on commercial and residential roofs. The resulting amount of electricity generated in this distributed fashion is amazingly high.
The report uses very conservative numbers for solar PV cost improvements - a breakthough like the one mentioned in this article would make the market penetration even higher.
I was shocked (and pleased) to find out that our government has done this kind of research - I hope "W" doesn't find out or he'll cut off their funds!
I just discovered this report myself, and will be blogging about it this week, but I thought I'd pass it on since you asked...
Nils
Re: Small scale individual solar
You posted while I was writing. I agree about the importance of the great question, because it helps to lead. The issue remaining is how the retail market gets widely open to business model innovations competition to replace the obsolete price controls business model. An EWPC EPAct is highly recommended to enable such business model competition.
I suggest reading the EWPC article, Let’s Avoid Many Expensive Fiascos, whose summary states “There is no need to cite any [analytical] evidence ‘to enable a highly competitive, pro-consumer, complete and fully functional market architecture and design paradigm shift.’ What is needed is to have ‘the global power industry … get out of the wrong jungle to produce a EWPC based EPAct as soon as possible.’”
Re: Small scale individual solar
Not everyone thinks of large scale solar production. My post above Is this a Disrupive Technology?, is precisely about how to integrate small scale distributed solar production for the benefit of people even the poor at the BoP.
A selection of my posts on this website Who is Afraid?, Demand Side Barrier, Small is Beautiful, A Barrier to this Potential Breakthrough, Off-the Grid Developments are representative of all posts on the Electricity Without Price Controls (EWPC) market architecture and design paradigm, which is the emergent paradigm that makes “such technologies feasible,” but not off the “grid,” to actually fulfill the late Fred C. Schweppe vision, as post on Comment on November 2004 Issue - Write and Wrong.
An excerpt of the post says: “Contrary to the belief that IEEE Spectrum was wrong, Professor Fred C. Schweppe, of MIT, brilliantly predicted a mayor tech breakthrough in electric power, when he said that ""There is a good chance that by the year 2000 the term blackout (societal definition) will be considered to be a term out of the Dark Ages." The chance has been there all along, except that a powerful lobby has prevented it, by keeping the natural monopoly of distribution related or integrated with non monopoly retail marketing.”
What you are suggesting is commented on the post Everyone for Himself Solution, which I will repeat in full with a minor upgrade by adding a link to “javs”:
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 competition, 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 to read about the EWPC market architecture and paradigm that makes the grid a two way street.
Re: Small scale individual solar
The point is 100% true, electricity has been developed in a central, concentrated,controled net, as so many other things it is becoming personal size.
Information, education, transportation,etc are becoming more and more "personal" and energy production will be too.
There is no coincidence that there are only 2 major suppliers of purified silicon ( another 5 will come into the market soon).
A day will arrive where you will be able to build your home away from electricity grids and have all what is needed from yourself.... without central companies charging you and this is something you will see starting in a few years
I guess my problem with this article is that it seems like just another in a long list of similar articles over the past year or so. Each one has some "hook" to it concerning solar cell, cheaper, more efficient, etc., etc. and each one seems to "disapear" into oblivion, never to be followed up on, or come to the light of day.
If I did not know better (and I may not), it seems that this sort of discussion comes up with various technologies, right at a moment when "someone" wants your money, wants people to invest. Give people some "hope", give them a reason to want to and they will... it is human nature.
Then... take the money and run. Nothing has to ever come out of it all, since our collective memory will forget it and move on 5 minutes from now.
Seriously though... In the last several years, I swear I have read a dozen (or more) different articles on a dozen different "advancements" for solar cells that never seem to come about.
I had a similar immediate reaction to the article. I've seen so many articles like this in recent years, It's hard not to roll my eyes when I see a new one.
I don't necessarily think that they're just doing it for the money. A lot of these stories do seem based in real advances in technology. I think the problem stems from the fact that many of these articles are based on laboratory or experimental results. It's one thing to demonstrate something in a lab. It's another thing to raise the capital, mass produce it, bring it to market, and rapidly grow your market share to profitable levels.
I can see at least a few key stumbling blocks in that sequence. For instance, it's one thing to ask people to pay 8-10 cents/kwh on a monthly basis, it's another thing to ask for the next 15 years worth of electricity bills all up front. At the least, most people are going to need to finance such a decision, which adds interest charges, which means that it's not just good enough for solar cells to match the cost of other forms of energy, they have to beat it.
Another problem is installation. Building a factory capable of churning out state of the art cells en mass is easy compared to training the work force to install them if you're going to sell any kind of volume.
I think solar cells are on a bit of a teetering point. They look good on paper compared to other alternatives, but there are practical challenges that they face that make them lose out in most cases.
On my post Is this a Disrupive Technology? and my two posts under Small scale individual solar , under this article, there is an underlying message that I posted today elsewhere as A Barrier to Capabilities on the Grid.
The question is: What effect has a flawed restructuring of the power industry (i.e., keeping the retail market closed with an obsolete monopoly business model insteado of business model innovations that will help integrate distributed solar, wind, etc., generation and storage) on resuts?
In addition, the post Re: I hope its a breakthrough also applies and says:
I also hope it's a breakthrough. Researchers are like baseball players they make homeruns, but also strike out. What's needed is that they keep taking turns at bat. At some point the solar home run is bound to come.
To increase the incentives for researchers to take turns at bat, I have suggested to take down the barriers on the development of the resources of the demand side, as follows:
The electric power industry regulations have a strong barrier to the development of the resources of the demand side. For any solar power breakthrough to be integrated to power system planning, operation and control a new market architecture and design is required to eliminate said barrier.
The article is a good contribution to TR readers about one of the most important kinds of uncertain generation.
Skeptic, I concur 100%. The worst technologies for this type of 'vaporware' are cheaper, more efficient solar cells! and cheaper, more efficient LED light bulbs! I was reading one just tonight about the technology available now - printing solar panels on plastic sheets with an inkjet or silkscreen printer. With the caveat '"Someday" consumers will be able to print their own solar cells, slap them on the roof, yadayadayada...'
Didn't we just read a few weeks ago that some clever fellows at MIT had come up with a better way of slicing silicon off of the ingot by using wire EDM had been accomplished. If so it should be possible to slice the 100µm thick substrates. Lets get these guys together and start producing these things. Great work guys.
Just a thought why not build the backside of the mirror into parabolic troughs that can focus the incoming light onto narrow strips of the active silicon nmaterial and get a much bigger gain out of the expensive stuff.
Re: thinner silicon substrates
I had the same initial reaction, for the same reasons. "What, again?"
After thinking about it a bit, I realized that most of the innovations in solar I've been reading here happened in the past few years, and some were really just proof-of-concept.
Also, you have to take each improvement individually; obviously you can't take the 2% increase from on article, add the 3% from another and the 20% and 30% cost reductions from two more and get +5% at half the cost. Some of these are very similar improvements to the same aspect of solar power, and the deluge of them creates an illusion of enormous growth that never comes to fruition. But, while it's not improving as fast as this makes one want to think, efficiency <i>does</i> keep increasing.
A number of years ago the Northern Alberta Solar Energy Society, along with the University of Alberta, sponsored a summer clinic where Wang Lee, an engineer/architect from Calgary, who had worked on some solar powered projects in his community, came and divided us into groups of six in order to show us how to construct a cheap and very efficient solar powered water heater similar to the one which he had installed on his own home. This was a simple system of copper tubes soldered together which were painted black and held in place with some angle iron, had a few feeder valves, etc. and was faced with some even simpler acrylic sheeting to intensify the effect of the incoming solar rays. The model that was eventually installed on one of the heritage buildings on the University grounds, worked like a charm the very first time it was connected and was capable of providing enough relaible hot water for a family of five. And if I remember correctly, the total cost of materials was about $120.
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protn7
72 Comments
Other risks
The capitalists took a risk on their product; silk screened solar cells. Vulvox offers similar risks and similar promises. If you asked an investor its' well worth taking. That technology was shown to work in the lab many times. A knowledgeable investor would understand the risk was worth taking since there were already signs it would work. http://vulvox.tripod.com
Reply
lasertekk
146 Comments
Re: Other risks
This are not the time to be using words like 'capitalist, risk or investor' on a science and technology site, with the second storming of the Bastille being contemplated by middle America. There's a reason some of us took the science major route and stayed away from the filth and greed that was business.
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Monsterboy
92 Comments
Re: Other risks
Like it or not, the science will go nowhere without investors to pay for it. Technology is the offspring of science and money.
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