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New Solar Cell Sets World Efficiency Record
asoduk writes to tell us that a new world record has been set for the most efficient photovoltaic device. Topping the scale at 40.8% efficiency, the new solar cell differs significantly from the previous record holder. "Instead of using a germanium wafer as the bottom junction of the device, the new design uses compositions of gallium indium phosphide and gallium indium arsenide to split the solar spectrum into three equal parts that are absorbed by each of the cell's three junctions for higher potential efficiencies. This is accomplished by growing the solar cell on a gallium arsenide wafer, flipping it over, then removing the wafer. The resulting device is extremely thin and light and represents a new class of solar cells with advantages in performance, design, operation and cost."
A new efficiency record is nice and all, but most people have more than enough room on their roofs to power their homes with current efficiencies. What's really needed for solar PV is to be much less expensive. When I can get a complete system installed for $1/Watt, I'd gladly switch to solar. And before someone mentions Nanosolar, they hope to eventually get down to $1/Watt, and they have limited production, which is already sold to Germany. End-users cannot get anything from them.
Indium is a very rare material, one which we're slated to deplete in less than 10 years or so at current rates of consumption, due in part to its use in display screens.
I highly doubt that widespread use in solar cells would be feasible.
Nice efficiency, though.
Kythe
Shhhhh! don't give them any ideas or the next thing you'll know the goverment will be selling the rights to collect sun. Don't laugh, do you know it is unlawful to use rain barrels in Colorado? "Because rights to water are legally allocated in this state, an individual may not capture and use water to which he/she does not have a right." Next sunbeams?
Si vis pacem, para bellum! For evil to succeed good men need only do nothing!
While I agree that these types of announcements are overblown (they are talking about high-concentration PV here, which is not a good idea to put on roofs at all for structural reasons, and it only responds to about 80% of the available irradiance anyway due to being limited to beam radiation), the ROI is highly dependent on the economic conditions of the owner. Solar can payback fast if you are a large electricity user in the upper tiers of pricing even without incentives, and with incentives the banks are loving it today in many locations. If you are off-grid in a sensitive environment, you may have little alternative... what is the ROI on that? If you are living in a tiny home in a mild climate with no air conditioning, your ROI could indeed be prohibitive... but blanket statements about ROI are NOT "insightful", moderators.
How much do they cost and when can I get some?
If the goal here is to move away fom the consumption of materials in short supply, solar cells based on gallium and indium aren't going to help. We had a world-wide gallium shortage at the turn of the millenium, and that only receeded because demand slacked off some. There is currently a shortage of indium that started in 2007.
Both of these elements are hard to come by because they are not just rare, but sparsely distributed. Indium is produced from lead, zinc, and tin production waste, and I think gallium mostly from aluminum production waste. I'm sure supply will increase over time, but we can't quickly ramp up production of either element by "mining more".
Niether of these elements would remain economical if there were a sharp spike in demand.
Socialism: a lie told by totalitarians and believed by fools.
Why does everyone think these would be used to produce electric power for domestic use? Something like this is much better suited for use on spacecraft.
When you are covering your roof you care about the power/cost ratio. On spacecraft you care a lot about power/weight ratio. This new type of cell address power/area which translates directly to power/weight
Please choose a doctor:
A. Doctor McCoy, who's going to make you take some magical pills and ask you to get a good night sleep.
B. Doctor Crusher, who'll treat you and then send you to counselor Troy to deal with any emotional damage.
C. Doctor Bashir, who'll invent a whole new treatment because he can't be bothered by "ancient techniques" created by normal humans.
D. The Doctor, who'll simply laugh at you while mentioning something along the lines of "hologram can't be harmed by such trivial things".
E. Doctor Phlox, who probably has some kind of alien leeches he can put on you to drain out the toxins.
F. The Doctor. He's not a real doctor, but I guess he could send you back in time to warn yourself not to do that in the first place.
Your math reads, to me: 400W * 4 * 8 hours * 365 days = 4,672kWh/yr
Unfortunately, both the 8 hours per day and the average usage per year are incorrect.
Average electricity use in 2001 was 11,965kWh/yr [ US EPA ]. Average solar power insolation in the US is around 4.8kWh/day [ Solar Insolation for U.S. Major Cities ] (caveat: I took the average of the listed cities averages, so it'll be skewed towards more populous regions in the US)
Therefore, 11965/(365*4.8*400 = 17m^2 of this material, just to generate enough energy over the course of the year to net zero over the power company's input. If you want to be grid free, you need to size for the worst case (winter), which is 3.75kWh/day, or 22m^2. That does sound like a lot, but then again, 22m^2, is only about 5m by 5m (15ft x 15ft). Even a single story 1000 square foot home has at least twice that on each side of its roof.
I'll note, though, that this average probably includes air conditioning and electric heat, which are huge energy sinks. But then again, if they're what people want, then they'll need to be able to support them in their system.
hey... Thats my argument!
If we built 10 thousand square miles of solar thermal power plants in the US southwest and a few hundred feeder-breeder reactors elsewhere, we could completely replace the low efficiency and high pollution electrical production of the US while expanding our capacity to be 2 or more times its current amount.
This would allow us to also switch over to grid powered electric rail lines and widespread use of economical electric cars. Even without dramatically improved battery technology, long distance private vehicles could become viable if a charging rail system was installed along interstates and major highways to allow short range EV to charge on the move.
The cost of the initial investment would be high (a few trillion) but over the course of a few decades it would easily pay for itself (assuming electrical rates similar to today).
Wow.. I thought you had to be making some weird joke or obscure reference that I didn't get...
But no, a quick bit of googling reveals that this is indeed true - and on top of this, apparently in Colorado tap water is to be used once and once only - any secondary ('gray water') usage is also unlawful.