Transparent plastic solar cells fitted into windows

Solar company Konarka has developed a transparent solar cell that it hopes will be built onto electricity-generating windows.

The Lowell, Mass.-based company on Tuesday said it has reached an agreement with Arch Aluminum & Glass to use Konarka's plastic solar cells in building materials, including windows.

A transparent solar cell Konarka hopes will be fitted into power-generating windows.

(Credit: Konarka)

Under its Arch Active Solar Glass development, the company has built prototypes of windows with the solar cells between two panes of glass. The photovoltaic cells can be tinted different colors.

"It is energy-efficient and transparent with superior vertical performance and a subtle red, blue or green aesthetic. With these features, BIPV (building-integrated photovoltaics) will no longer need to be confined to spandrel or overhead applications," Arch CEO Leon Silverstein said in a statement.

Konarka makes organic solar cells made from flexible plastic. Last fall, it opened a factory in Massachusetts to manufacture the cells which come off assembly lines as spools fitted with wires to carry electricity.

The advantage of these flexible cells is that they can be used for a wide range of applications, such as power-generating military tents, portable chargers for electronics, and sensors.

Photos: Building on flexible solar cells

But these organic photovoltaics aren't very efficient at converting sunlight to electricity and won't last as long as a rooftop solar panel, which is typically under warranty for 25 years. Konarka said late last year that it achieved 6 percent efficiency in its labs but that's not yet available in its products. A high-efficiency silicon solar cell, the most common cell material, can be over 20 percent.

Konarka's factory is turning out red solar cells but has started making the transparent cells in limited runs for prototypes and development, according to a representative.

Although Konarka has raised over $100 million and has signed a number of partnerships, there are many people who are skeptical that the company can be profitable.

"The real key will be to see if they can make building-integrated products that can stand the weather for 20-plus years," clean-tech venture capitalist Rob Day from @Ventures told Greentech Media in December last year.

Konarka also faces growing competition in the building-integrated photovoltaics field. Thin-film solar manufacturers, including Heliovot, also make flexible cells that can be fitted onto glass or building structures such as awnings but are more efficient. Nanosolar's cells made from CIGS (copper indium gallium selenide), for example, are in the 9 percent to 10 percent range.

[professionaladventurer]

All this photovoltaic technology is great. I wonder when all this stuff will become available to consumers. I have an off grid place in Hawaii (www.paliuli.com) and I am still stuck using 130watt 2x4 ridged PV panels and golf cart batteries because I can't find an outlet that sells all the great new tech (at a cost effective price) to consumers.

[Vegaman_Dan]

The return rate of investment isn't quite there, but it's a start. I like the idea, and hope eventually the amount of research that results in Moore's law in computers will take effect in our energy production methods, especially in solar and wind sources.

[Warhaven]

That's nifty. 10% solar conversion on every window in your house. if you have efficient windows to begin with, this would nicely offset any temperature differential those windows allowed -- heating & cooling. And 25 years isn't too shabby, either. So, twice during the life of your home, you're going to replace the solar cells in your windows. I wonder how much they cost...

[Sam Papelbon]

the 25-year figure is referring to traditional solar panels, not the translucent ones.

judging from the pictures, it looks like they are still pretty dark, and hopefully they don't have to be arranged in that stripe pattern and can be made into a solid panel. otherwise, another application might be to use them as blinds. it would make sense as you would likely put them up if the sun is shining in, and take them down when it isn't. not sure if this would increase the lifespan or not.

[iptofar]

Moore's law has nothing to do with PV. They've been working on them for over 30 years and have only marginal increases in efficiency and decrease in costs.

If ROI is negative on regular panels, ROI on transparent panels is the equivalent of setting money on fire and watching it burn. Sorry for the flame.

[RompStar_420]

I think the ROI (return-on-investment) will eventually work, once the cost of these technologies comes down. I can't imagine the process of making them be so expensive, just to loosen up the control over these inventions so that it can benefit the planet and everyone, not just human monkeys.

[NocturnalCT]

I'm not sure these would be so useful for home owners. We typically have limited amounts of window glass and we like to look outside. I think home owners would benefit more from cheaper roof mounted panels. The roof is 'useless' right now so mounting panels on them doesn't really interfere with the rest of the home. Integrating panels into the roof itself would be even nicer of course but retrofit (mounting on existing roofs) is where immediate growth would be.

Now tall office buildings have a problem that their roof area is too small to make use of traditional PV panels to generate more than a tiny fraction of their electricity needs. I think it was in that Discovery Science show where they looked at technologies for mega cities in the future where they proposed putting solar panels (concentrators or otherwise) on roof tops. Absurd, even if 100% efficiency could be reached. So covering the East, South and West sides of tall buildings with these semi transparent solar panels might actually work. Stop your worker bees from looking out the window and generate some electricity at the same time :)

Maybe someone will turn these flexible solar panels into curtains that you can use to block the sun (from the outside) while generating power. That seems more usable than blocking a window permanently, at least for home uses.

[RompStar_420]

There is this cool thing I once saw from an undergraduate student form some technical school (I don't remember which school anymore), but she, yes a "she", not a "he", created these floor tiles, it wasn't that complicated, it used Piezotronics components, when these things bend, they make electricity.

So, when people walk down a busy (area) whatever that is, they made electricity, it worked quite well.

Imagine doing something like that on a busy street in New York or Japan, or anywhere lots of people walk.

[NocturnalCT]

There is no free energy. If you succeed in harvesting energy from pedestrians then it's either a) an insignificant amount or b) they'll notice because walking becomes more tiresome and wont want to walk on that street anymore.

Not to mention that the cost of these tiles and wiring plus conditioning electronics must be considered in any cost/benefit analysis.

This idea is just as silly as that project on TV a while back where they attached a generator to the revolving door of an office building. Either you make people push hard and generate real power (and make 'em mad) or you make it so they don't notice and then it generates no power.

Here's the 'pink glasses that's so cool' link:

http://www.groovygreen.com/groove/?p=2633

and a bit more realistic:

http://www.halfbakery.com/idea/Revolving_20Door_20Power_20Generator

It's funny that well meaning people that want to save energy actually waste tons of it on such ideas when a 5 minute back of the envelope viability check is enough to see this won't go anywhere.

Sorry to be cynical today.

[Sam Papelbon]

well, the input for a piezoelectrical tile doesn't have to be added, it's already being used by everyone who walks down sidewalks already, it's just being used for nothing more than pushing down on some concrete. the only way your 'heavy revolving door' analogy works is if a law was instituted saying that people walking down a path covered with these tiles had to stomp and/or jump.

piezoelectronics doesn't produce very much electricity, though. it's been used in things like watches and lighter/grill ignition.

[sew03]

even if the return was small, so what? we need all the power we can get

[narfzorkpinky]

http://www.innowattech.co.il/

It is already happening... in Israel and the UK! Costly, but happening.
They get high power from it, too.

[chuchucuhi]

If you mixed that with windows that have a variable tint that is controlled through electricity you could really save some energy running the new windows and keep the heat out in the summer.

[BtmnHatesRbn]

Now, let's do solar-celled spanish roof tiles, solar-celled paint, waste burning turbines with paper pollution scubbers, etc. so get people off of the power grid and save the oil for cars and boats and planes.

Yeah, I'm actually a Far Right Constitutionalists, and I also know how to make people so-called "green" and Americanlly independent from the slaving by utility companies.

[cocobolo-sungod]

It's always interesting to read comments related to solar energy. Lots of people seem to be experts. I wonder out loud how many of the above posters are actually living either completely or partially on solar power.
I live off-grid, and have been using solar electricity (PV) for nearly 12 years. Even with that, we still require additional assistance with our power needs. Therefore, a generator is part of our arsenal. It is used as little as possible - and essentially not at all during the summer months.
I am a little disappointed by all the percentage conversion ratios commonly touted for solar panels, so here's the straight goods.
An amorphous panel will convert about 6% of the energy striking it into usable electricity.
A polycrystalline panel about 10% and a monocrystalline panel about 12%.
Yes, I know that every manufacturer will make higher claims, but these are real world figures.
Their claims are actually quite factual, but that is in their laboratories under strictly controlled conditions.
Expect the cost of solar electricity to drop drastically as soon as the new type panels, which will not be using silicon, hit the market.
Google put some seed money into a company in California, Nano-Solar. They are producing working panels which cost about $1 per watt. Unfortunately, you and I cannot buy them yet. It is my understanding the full production run is headed over to Europe. They have another plant in Germany (I think) which is already in production. And in fact have even paid their first stock dividend!! That is truly remarkable!
There is at least one other company in the US producing a very similar panel, but again, they are only letting out fairly large volumes of the panels at a time. The intent is to provide power generation to a wider audience. It is only a matter of time before more companies begin to get on this technology and the panels hit the main stream.
At that time, with these panels selling at $1 a watt, (+ or -) the power generated in that fashion will be more than competitive with coal fired generating stations. The other benefits will be so completely overwhelming that coal fired electricity should then be phased out as rapidly as possible.
It is simply a matter of getting the production capacity of these panel manufacturing plants to massively higher levels than they currently are. It will take time, but it will happen.
In the mean time, the best thing that all of us can do is to conserve electricity.
How many of you leave your TV, DVD players, computers, water heaters etc turned on all night long? Just asking. Think about it.

[bob1xxxx]

Hmmm interesting Idea but a real world product sound about 5 to 10 years off.

[jwjaso]

It seems like ROI is a long ways off for consumers on these which is the biggest hurdle for solar to become standard in homes. Technological advances are great but if the cost is too high, few will benefit and we continue the conundrum for solar to take off in US.

[Dr_Zinj]

I fully expect my home to last longer than 50 years.

[Heebee Jeebies]

Are they just stupid. 6% efficiency, I can get that flapping my arms with wool socks on. Inside the glass of your windows instead of on it? What they expect you to spend $20,000 or more every couple of years to replace your windows because their poor solar cells took a dump? Are they just stupid?

Robert

[Altotus]

Organic 3rd generation should be cheap and easy to apply however not like paint out of a bucket. I think the efficiency will not improve greatly for this particular product (transparent coating). However it should have a lower cost once in full production perhaps $25-$150/m2 don't put much weight on the estimate thats just a guess I pulled out of the air but definitely their shooting for that $1 a watt or less however time will tell but the organics offer a possibility of a low cost product and as development goes on higher efficiency and product life. The cool thing is have your light and get power too I suspect the cells work in the infrared so it may cut cooling cost a small amount. I see the company is a small venture capital company so its not public.

[kenstech_com]

I think trying to monetize any solar technology on a 20 year plan, or even a 10 year plan is madness. The technology is and will be changing so rapidly that if you can't make yourself profitable quickly, you wont be at all. Someone else said that PV doesn't follow Moore's Law. Strictly speaking that may be true, but they are subject to what Kurzweil calls the "Law of Accelerating Returns" The prior 30 years were essentially the flat part of the curve. Now with higher demand for energy resouces, you can expect that curve to start to show up. The reason PV technology as remained static for so long has a lot to do with the abundance of cheap fossil fuels. Now that energy demand is skyrocketing I expect to see a lot of the prior investment in research to begin to pay dividends. These transparent solar panels are just the beginning.

Ken
http://www.kenStech.com

[gobotnik]

We've got to get over the idea that a quick Return On Investment is necessary for solar. It is not about free energy, it is about clean energy.

[JohnWolfendale]

This just seems to be a dream come true. if all the windows were generating electricty we'd significnatly reduce our carbon emmissions.