$1/watt solar panel - $2/watt solar system

http://www.nytimes.com/2007/12/18/t...1b06819623f9d0&ei=5088&partner=rssnyt&emc=rss

To good to be true?

 

Australia has been slack in making any headway with renewable energy but there is a change of direction now.

Solar works well in distributed systems and I believe it is an economic energy source now for household use in Australia - we have bright sunlight most of the time during daylight hours. I don't think there is anything in solar panels that will make them increase in cost as they build volume. Current observations are that costs are comming down and performance is going up.

I have the opinion that energy storage will become a constraint because there is simply not enough lead to start cars and store energy for overnight use. Lead has increased in price dramatically in the past 5 years. I bet the growing number of electric bikes in China is one reason.

Solar energy is practical now for many uses and I expect to see strong growth. A new president in the US might increase the momentum for renewable energy rather trhan simply trying to protect oil supply.

Rick W.

 

As I recall, the Nanosolar claim is based on a radically new manufacturing technology that allows them to "print" the photovoltaic cells in a much simpler way than the customary silicon wafer cutting...

As those prices, it would indeed be a revolution for solar power, at least here in the U.S.

 

This is utter nonsense.
A photovoltaic panel must be able to withstand 12 Bf wind, hailstorms, rain and extreme temperatures for at least a decade, so it needs tempered glass and a stable, corrosion-free mechanical structure.
To generate 100 Watts with state of the art crystalline silicon cells and area of nearly 1 sq.m. or 9 sq.ft. is needed. Assuming that the low cost printing technology is just as efficient (it probably does not even come close), such a panel should cost less than $100. Just the tempered glass, anodized aluminium, junction box and UV resistant polymer sealant costs more than that.

A more basic approach would involve plastic film over the photovoltaic aluminium substrate and a reinforced plastic frame, but I doubt it will last 10 years outdoors. Similarly constructed low cost panels presently on the market all suffer from capillary action causing galvanic corrosion. That may be acceptable for recreational use, but not for a serious power plant.

 

"Utter nonsense" is a bit harsh, don't you think? Here's a quote from Popular Science's award of Innovation of the Year for 2007. Be your own judge.

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"The company produces its PowerSheet solar cells with printing-press-style machines that set down a layer of solar-absorbing nano-ink onto metal sheets as thin as aluminum foil, so the panels can be made for about a tenth of what current panels cost and at a rate of several hundred feet per minute. With backing from Google’s founders and $20 million from the U.S. Department of Energy, Nanosolar’s first commercial cells rolled off the presses this year.

Cost has always been one of solar’s biggest problems. Traditional solar cells require silicon, and silicon is an expensive commodity (exacerbated currently by a global silicon shortage). What’s more, says Peter Harrop, chairman of electronics consulting firm IDTechEx, “it has to be put on glass, so it’s heavy, dangerous, expensive to ship and expensive to install because it has to be mounted.” And up to 70 percent of the silicon gets wasted in the manufacturing process. That means even the cheapest solar panels cost about $3 per watt of energy they go on to produce. To compete with coal, that figure has to shrink to just $1 per watt.

Nanosolar’s cells use no silicon, and the company’s manufacturing process allows it to create cells that are as efficient as most commercial cells for as little as 30 cents a watt. “You’re talking about printing rolls of the stuff—printing it on the roofs of 18-wheeler trailers, printing it on garages, printing it wherever you want it,” says Dan Kammen, founding director of the Renewable and Appropriate Energy Laboratory at the University of California at Berkeley. “It really is quite a big deal in terms of altering the way we think about solar and in inherently altering the economics of solar.”
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No, utter nonsense is exactly what I meant to say.
Not to the manufacturer of these thin film panels, but to the journalism around it. If you can't do the math, don't write about such topics.

This Popular Science quote also falls in that category:
- "Traditional solar cells require silicon"
What you you think Nanosolar uses?

-"exacerbated currently by a global silicon shortage"
Are the beaches of this world gone? They are made of silicon oxide!
In fact it is available in unlimited quantities, it is the cleaning process that makes it expensive.

What Peter Harrop meant to say is that the energy needed for production of silicon cells is currently $3 per watt and has to go down to $1 to be competitive with coal. Because thin film semiconductors use less raw material they are cheaper.

To compare solar energy with other sources you should calculate the cost of the generated power during the life expectancy, including installation, weatherproofing, converting it to a transportable format like 115/230 VAC and storing it until it is needed.

 

Wow, you're just a little too angry to read well, I guess.

You said, "What you you think Nanosolar uses?"

"Nanosolar’s cells use no silicon, and the company’s manufacturing process allows it to create cells that are as efficient as most commercial cells for as little as 30 cents a watt. "

What part of "use no silicon" don't you get?

 

Grumpy perhaps, not angry.

But I stand corrected: Nanosolar doesn't use the abundantly available silicon, they prefer gallium-indium-arsenide. A semiconductor material for LED's and solid state lasers, not exactly cheap because these metals are quite exotic, but easier to purify than silicon because they are very soft. It is also less stable than silicon.

A quick Google search with "Nanosolar efficiency" as keywords shows 32.200 results, from which the first 5 figures are:

-"With 19.5% efficiency under standard test conditions, the best CIGS cell is about ..."

-I heard that the technology was invented by Chris Eberspacher (current VP of Nanosolar). Efficiency of its module is around 7%. Any comments? ...

-Nanosolar says their efficiency is 9-11%, and their cost of manufacturing is about 1/10th the cost of traditional polysilicon cells. ...

-Nanosolar is on track to begin producing nano-PV building modules by 2006. ... the standard 12–18% efficiency rate at which today’s conventional solar ...

-you have to see what the efficiency of the nanosolar product is to guage its cost effectiveness. I doubt their efficiency is anything north of 8% ...

This confirms what I wrote about journalism. It probably already starts with a PR guy who doesn't really know what he is talking about and forgot what he said yesterday and a reporter who cannot read his own handwriting.

So what is truth and what is fiction?

Printing thick film is no big deal, the process is used in hybrid circuits for over 40 years. Making thin film that way, instead of vacuum depositing, is quite an achievement. For the sake of the argument, let's assume the purity, layer thickness etc. are just as good.

Around my house are 6 crystalline Siemens solar panels, 3 thin film panels and a polycrystalline flexible panel. There have been more when I started experimenting 13 years ago, this is what it left. One Siemens panel was torn away during a storm, hit a rock and shattered, 3 thin film panels degenerated and several polycrystalline units were not properly sealed so the saline sea air destroyed them.
Only the Siemens panels still perform as they did from day one: 1 sq. m. generates 100 Watts in direct sunlight (1 KW/m2). You can argue about the efficiency being 10% or 12%. If you count only the active silicon surface it is 12% but including the mechanical parts and gap between panels, the efficiency is roughly 10%.
The thin film panels are very expensive glass roofs as used by Audi for their A6/A8, now 5 years old. When new, the efficiency was around 7%, now it approaches 5%. The appearance has not changed. Under less than full sunlight conditions the efficiency drops even further because the output is far from linear.
The polycrystal was 8% and now -after 5 years- is below 5% because the plastic in which the cells are embedded gets dull and yellow.

In my humble opinion, only a solar panel that has the life expectancy and performance of crystalline silicon, with a thin film price tag, would be a breakthrough. And even then, 1 watt electrical energy from 10 watts of solar radiation is only acceptable because governments have not yet invented solar tax.

 

Well, the panels are in production now, the first have been delivered. Let's see what they deliver in the real world.

 

Here’s my $.02 - I’ve seen claims before – many times since the 70s when I was in college studying electrical engineering. Companies make incredible claims, which they back up on paper with some information written by the marketing guys – usually guys with little knowledge of the chemistry or production process. The press gets the story and reports the optimistic side of the marketing guys information. This may be a tactic to get grant and investor money – that’s my guess anyhow.

CDK makes a good point about the longevity of the cells – anything that is polymer (plastic) will deteriorate in sunlight, and I’ve seen panels that drop to almost no output because the polymers used in their manufacture turn yellow or opaque.

It would be nice if solar cells can be printed in a simple manufacturing process. People have been working on this since at least the 70s that I know of. Maybe someone will get it right. Maybe Nanosolar will have a breakthrough. I’m not holding my breath waiting though. I am the head engineer for an electric cooperative and we are getting ready to spend $1 on photovoltaics. I don’t think we will be spending our money on anything that is likely to degrade into uslessness in 5 years, unless it is 30 cents a watt.

 

that should say $1,000,000

 

So what if the solar cells are cheap or even free. Its not the solar panal where the problem lies with solar its the Battery.

The initial cost of the battery and the inverter to convert from 12v dc to anything AC is enormouse. Then the expected life of the batt's and the inverter is 5 years. I did the math once. It was cheaper to buy a generator and the diesel, every year. then to put solay/batt/inverter in. I mean you can buy a 2.5 KW Gen. USe it for a year, throw it away, get another, and do it again. Untill these costs come down, or the life of these systems gets longer solar is a dead issue.

My $0.02

 

$100+ for 1 m2 of tempered glass, 4m of extruded aluminium, a junction box and some silastic? You should get your wife to shop for you.

 

My wife does in fact most of the shopping and I am quite satisfied most of the time. She says that you need 6 m aluminium an make two panels with 3 mm Corning glass to meet the storm/hail requirements.
And she asks if any attention must be paid to heat sinking. I think she makes a point there.

 

issues

Did the costs not just come down?

Durability, nanosolars claims 25 years, hard to believe with a printed coating.

Solar is a dead issue as long as the sun will keep fading away the next decades while the oceans fill up with crude.