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New Record For Solar Cell Power Efficiency
Posted by
kdawson
on Wed Aug 01, 2007 05:14 AM
from the onward-to-50% dept.
from the onward-to-50% dept.
mdsolar writes "Renewable Energy Access is reporting that a consortium led by researchers at the University of Delaware has achieved 42.8% efficiency with a silicon solar cell. The method uses lower concentration (factor of 20 magnification) than the previous record holder (40.7% efficiency) so that it may have a broader range of applications, since tolerances for pointing the device will be larger. They are now partnering with DuPont to build engineering and manufacturing prototypes. They expect to be in production in 2010. On a roof, such cells would require less than half the surface area to produce the same amount of power as today's standard solar panels, which have an efficiency of about 17%."
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Solar Cell Achieves 40% Efficiency 632 comments
Fysiks Wurks found on the U.S. Department of Energy website news of a breakthrough in solar energy efficiency. From the article: "...with DOE funding, a concentrator solar cell produced by Boeing-Spectrolab has recently achieved a world-record conversion efficiency of 40.7 percent, establishing a new milestone in sunlight-to-electricity performance." A page linked from Wikipedia's article on solar energy calculates the land area that would need to be covered by solar collectors at 8% efficiency to meet the world's energy needs (using 2003 figures). At 40% efficiency, it looks like a square 265 miles on a side in the American southwest would do it.
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Science: Solar Power Headed For 45% Annual Growth 402 comments
mdsolar writes "USA Today is running a pretty good article on solar power that gives an overview of the current state of the industry. Highlight include production costs of $1.19/Watt for First Solar, 40% annual cost reductions over the
last five years, revenues expected to triple in three years, and a prediction for 2014 as the year when solar photovoltaic power plants become cheaper than other forms of generation. From the piece: 'Like wind power, solar energy is spotty, working at full capacity an average 20% to 30% of the time. Solar's big advantage is that it supplies the most electricity midday, when demand peaks. And it can be located at homes and businesses, reducing the need to build pollution-belching power plants and unsightly transmission lines. In states such as California, with high electricity prices and government incentives, solar is already a bargain for some customers. Wal-Mart recently said it's putting solar panels on more than 20 of its stores in California and Hawaii. Google is blanketing its Mountain View, Calif., headquarters with 9,212 solar panels, enough to light 1,000 homes.'"
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Smog (Score:5, Funny)
Waiting (Score:5, Funny)
hmmm. (Score:5, Informative)
The main problem is the general public. Everybody wants wind power (but not in their back yard) you have to actually change the law and rubbish collection to get them to recycle, and everybody needs to buy the latest and most powerful gadget on the market.
Making a more efficient solar cell is an excellent step, but I'd be more interested in a more *cheap* one so they can be taken up on a mass scale.
Spot on. (Score:4, Informative)
I recently had a new lady move in with me... and she insisted on actually unplugging things like my stereo when we were not using it. I was skeptical about the benefits of this tactic to save electricity, but being a curious person I was willing to humor her.
By unplugging all of my electronic devices (there are many of them) when not in use we saved around $30 U.S. a month. Where was all that energy going? Not sure.
If you are the type of person that has electronics in every room give it a try for yourself. Even if you don't care about being 'green' you will likely see a difference in your energy bill. Either way you win.
Regards.
Parent
Re:Spot on. (Score:5, Informative)
Some equipment behaves nicely on standby. Use a Wattmeter to check how much your stuff actually consumes in standby mode; you'd be surprised how little some things consume when idle, and there is little use in unplugging these completely. You might also be surprised at the large amount of power drawn by plug in transformers (The "wall warts"). Removing these when you are not using them saves a lot.
Another good way to save without sacrificing convenience, is to use a "master-slave" power block with your computer. I have a lot of inefficient transformer power supplies next to the computer, for printers, routers, LCDs, speakers, etc. I installed a "master-slave" system, that will automatically switch off all this rubbish when the computer is switched off. The power draw of this system when idle is minimal compared to those transformers, and you don't have to switch off every individual piece of equipment either,
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Re:hmmm. (Score:4, Interesting)
Unfortunately, a lot of devices are always on, like DVRs, game stations with online access, and more. They do a lot of work at night updating databases, downloading new content, etc, and simply have to remain on. The fact that an XBox 360 doesn't spin down the graphic system power and down clock it's CPUs is a design issue we can change. An Apple TV box uses less than 20 watts when "asleep" and that included downloading content over wireless. Why can't the XBox and PS3 do that? They could even drop into an even lower power state when idle, spin down the HDD, and only "wake up" every 90 minutes or so to check for content without spinning the drive up again unless it needs to.
Unfortunately, there are even more devices we can't really do anything about that are the real sappers in the house. The cable modem, wireless router/firewall, VoIP modem, second access point to cover downstairs, possibly an extra switch to add more than 4 wired devices (I have 7), and base station and answering machine for wireless phones. That's just the network. Now add the garage door opener, automatic sprinkler system, home alarm and smoke detectors (most run on house power and rechargeable batteries now), safety lights in your halls and bathrooms (night lights), and several clocks.
I work for a computer systems manufacturer. We've got a meter (magnetic ring type thing) at the office that encircles a power line and displays the power being used by the device. We have it so we can document in our white papers the power consumption of our devices. I brought it home and played with it a few months ago when having a forum argument with another individual on this. My 27" tube TV used about 2 watts when sleeping. My 37" LCD used less than 1. My PS2 used no power (but the transformer was using 2 watts). My cable box used 12 watts when asleep, DVR used between 20 and 50 depending on what it was doing when asleep. What surprised me was the coffee pot was using 3 watts when off (it has a tiny built in clock). The 2 alarm clocks we have each use 5 watts. Adding up all my idle devices I was just over 220Watts in use! 10% of that was in scent plug-ins around the house and night lights, about 20% was in our cable boxes alone. 25% was in devices I can't turn off, like the garage opener, stove clock, built in microwave, etc. Another 20% was in my home theater equipment (amp, dvd, vcr, and TVs). There were some other random devices around as well, not including my network setup...
After finding this out, I installed a "step on" power extension (like people use under the Christmas tree) in line between the wall and home theater, so I can press one switch at night to turn off all the device in the HT setup (except the DVR which has to stay pugged in all the time per the cable company or they'll void the warranty on the device). I threw out all the scent plug-ins in favor of passively diffused oils and popuri. I changed the few night lights we had out for LCD versions. I now have a programmable timer power strip in the computer room that I have 2 laptops, a small TV, a printer and a network switch hooked up to. Each night at 11:00PM the adapter cuts power to the laptops (which hibernate automatically after 15 minutes when on battery), my printers, the switch they're connected to, and the TV and cable box in there. My HTPC now uses sleep mode with Wake on Lan to save power and automatically shuts down and powers
Parent
Re:hmmm. (Score:4, Informative)
Things did get better when they started replacing the small turbines with fewer, much larger ones. The turbines closest to their house were removed, and the new turbines ran at much lower rpm which means they produce less noise.
As for sticking solar panels onto the turbine blades: this would make the blades heavier and less efficient. Also, you'd have to add slip rings on the root of each blade, and on the main shaft to transfer the power.
Slip rings are expensive, heavy and they need maintenance, especially when you're transferring significant amounts of power through them.
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Re:hmmm. (Score:4, Insightful)
Why are long term trends not taken into account in these reports, for example. It is rubbish to say that we cannot accurately predict climate that far into the future because our short-term predictions are not very good. After all, we cannot predict the little ups & downs in next month's weather, but we can predict that winter will follow summer and autumn, and we know what the trends are in each of those seasons. The long-term trends in global weather can be predicted as well.
On a geological timescale, we are in high summer. Winter is coming, and in 10.000 years we'll be in an ice age. The start of the downward trend in average temperatures is imminent (which means anywhere between now and 1.000 years)... Perhaps that is why the IPCC report does not look any further than the year 2100, the scary hockeystick curve will flatten out after that year, and if you look even further it will drop. Our distant descendants (if any) may even be grateful for the extra CO2 we have released, since it might make the next ice age a little less severe.
But with all that said, conservation and reducing our dependancy on a limited resource is a good thing. But I refuse to join in the mindless panic.
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Re:hmmm. (Score:5, Interesting)
Instead of making more money, people could work less. Instead of buying all sorts of shit, people could do much cleaner things such as talking, writing, riding a bike, going to a brothel, taking a walk, singing, playing a part on a play, painting, fighting (if not pushed too far it is not necessarily bad for some people...).
It is way too simplistic to say that there is a law of nature that says we will end up using every resource available. We are supposed to be rational beings even if we often do stupid things. One of the things of being rational (or partly rational) is that we can choose what we do. We don't simply answer any call of the wild (even if there is such a thing).
We are changing from a production society to a consumer one. We are becoming a bunch of morons that just sit and receive stuff. Not very different from the Eloi in H. G. Wells' The Time Machine. I don't think just consuming is satisfying enough. It is much easier (and faster) just to watch a movie than it is to tell a story and we end up watching 10 movies. Maybe a little boredom is good for creativity. It certainly is much cleaner than riding a car 100 km to do anything "new".
Parent
Solar cell? Pfftt..... (Score:4, Funny)
How much power? (Score:4, Interesting)
OK, but how much of a typical house's power would that supply? (I realize this depends on location and time of year.)
Or how many panels would it take to give you a daily, full recharge of a plug-in hybrid in, say, Los Angeles? (Imagine that that would do for LA's smog.)
Re:How much power? (Score:4, Informative)
Assuming you are going at work using 10kW (14 HP) average for two hours (both ways), and assuming 6 hours a day peak power, and your losses are zero, you need less than 15 square meters (160 square feet).
Now, if you add 50% losses in the recharge system (car and house), you need to double that - 30 square meters, or some 300+ square feet of solar installation, inclined to an angle equal to your location's latitude (equator- flat roof top, Alaska - sharp roof)
Parent
someone convince my local government (Score:5, Interesting)
why?
because my HOA (home owners association) does not permit them. As such it would take State or local laws to override the HOA; because in many States the HOA rules have strong legal backing at the State level.
This is akin to the problems satellite TV faced in many locales. There were numerous ordinaces, both at the HOA and local level which blocked satellite dishes. Even the small ones we are accustomed to today were blocked. It took a Federal Law to end that restriction. Unfortunately its going to take another such law to allow many of us to use renewable energy. Hell, I cannot even get rain barrels approved even though they would not be visible from the street.
Efficiency is less important... (Score:5, Insightful)
fail (Score:4, Funny)
Concentration Is Good (Score:4, Insightful)
But also the concentrators are a lot cheaper than the cells. The concentrator is usually a cheap (compared to the cell) lens or mirror. So a 20x concentrator gets 20x the input energy, but for a much lower cost than 20 cells. And that cell is operating at higher efficiency, on 20x the input. So a $10 cell fed by 20 $5 concentrators costs only $110 instead of $200. 5% more efficiency in the cell is applied to all 20 concentrators, not just the 1 cell, for 200% efficiency. So it's double the efficiency at 55% the price, or over 3.6x the $:energy efficiency. In reality, the concentrators are better than 5x cheaper, and the efficiency gains can go higher than 5% greater.
And then there's all the savings from cheaper replacement concentrators, which could even last longer than the cells (though the cells typically last >30 years), and dropping all the other HW from the 19 (or however many) extra cells in favor of "dumb" concentrators. In fact, since concentrators are so cheap, the cells might not require HW to track the Sun for maximum absorbtion, but just array the concentrators in an arc (or bubble) that always leaves an array of concentrators facing the Sun (and the rest off-axis), without consuming energy to move. Or extra parts, or computing, and saving all the maintenance costs, too.
So the more concentration, the better. After all, that's how the engineers thought up this stuff.
Put some things into perspective (Score:5, Informative)
I will try to put a summary to the interested folks around:
A photovoltaic system is composed today by:
- Module
- Inverter DC/AC
- Mounting system
- Cabling
- Measuring/Protection electrical stuff
Most of the cost today is the module. Systems go (net) for 4-5$/Watt.
More efficient cells (and modules) mean less installation costs. For the future, it will be important since cell and module prices will go down.
Today, in California, if you take a system lifetime of 25 years, the kWh equivalent "price" is about 25-30cent.
System price decrease is expected to be 5-10% yearly for the next 5-10 years at least. This means that very soon the PV power will be cheaper than the one sold by the utility.
PV systems are perfect for distributed energy: a centralized power plant is not really cheaper or more efficient than a 5kW roof installation. And the energy transport kills the small margin that you had in favour of the big thing. That is why most utilities are not hot about PV: it is against their business model.
For the moment, it is not cheap to get "disconnected" from the grid. Therefore, a mix of PV and other electricity is necessary. PV has a nice peak at max. consumption peak. However, the evening consumption must be covered otherwise. Wind, biomass, ocean waves, geothermal, whatever.
PV in order to charge e-cars is OK today already. A car that uses 10 liter to do 100km, at a 20kW mean power, is using 20kWh energy for 10 liter gas, at 1$/liter it would be 50 cent/kWh. Make the calculation with your local gas price/gallon and you see that, even today, it is competitive. And cleaner. Only e-cars are not yet developed/deployed as they need to be.
About Solar-thermal energy for cold- it works for mid-big sized equipments, it is cheaper and especially more reliable than electricity... PV supporting electrical AC is still a bit more expensive but both run a nice race.
Ah, the typical guy asks about energy payback times: depending on technology, after 1-4 years your system has produced the energy needed to make it. Longer times belong to PV prehistory and to right-wing-thinktank analysis.
Cheers!
Re:feasible (Score:5, Informative)
But in places like California, solar panels indeed pay for themselves
Parent
Re:feasible (Score:5, Informative)
A search on 'water cooled pv' [google.com] gives some interesting documents about experiments done with this combination. Read them and then go and build something like that. My 2 puny 11 watt panels are somewhat to small for this application but anyone who has (plans for) panels on the roof AND a need of warm water does him/herself a disservice by not looking in to this IMnsHO...
Parent
Being done in New Mexico (Score:4, Interesting)
--
Register your home for solar power; fixed competitive rates for up to 25 years: http://mdsolar.blogspot.com/2007/01/slashdot-user
Parent
Not too bad (Score:5, Informative)
Why didn't I get the ground based system? Because when it's over 100 F and your main AC unit dies, I couldn't wait for the ground based unit installation taking over a week. I will plan for one at my next house though.
Parent
Re:feasible (Score:5, Informative)
Parent
Re:What a pointless comparison (Score:5, Informative)
You can get at most 20 HP of power from that. In your real situation, with maybe 5 square meters of surface available in the morning, and lower solar power, and the 40% efficiency solar cells, you get 2HP (or 1.5KW). Does it help? A bit, yes. If your car can load itself all day with energy, and know when she will reach destination, she could bleed the electricity storage battery (and reload it later). This way, you could get 10 square meters of max power, 8 hours a day, and with perfect efficiency in rest (charge, discharge, motor) you get 80 HP hours - or two hours at 40HP. Good enough for a commute... but...
Now, you could buy solar panels at $5000 per kW (and 20 pounds). Assuming double efficiency is treble the price - you need $15,000 per square meter, so you'll pay $150,000 for solar on your car. Is it worth to drop your fuel consumption 50%? Or completely?
Parent
Re:What a pointless comparison (Score:4, Insightful)
This is the point where the central market planners jump in and shout that we should subsidize solar panels. But why does that solar panel cost $15,000 per square metre? Because of all the resources, energy, and labour consumed in producing it. Chances are those more than offset the gas you're not burning.
When the manufacturer can make panels efficiently enough to be more affordable than gasoline, it'll be because they're finally less wasteful and polluting overall.
A similar principle holds with recycling, by the way. In the instances where recycling actually saves on energy and raw materials, there is a cost savings as well, and the recycler will pay *you* for your bottles and cans. If the government has to make you do it, it's because the process is not cost-effective overall, and more waste is taking place in the recycling process than the recycling itself saves.
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Re:Another kind of efficiency (Score:5, Insightful)
I don't see energy getting any cheaper on this planet, and I don't see energy consumption decreasing.
The problem is it's not just the solar panels: it's the batteries and other infrastructure (and then maintenance!), and the last time I looked at it, it was closer to 20-yrs to pay back a whole system, and the system had a 20-yr life expectancy. That's break-even assuming it makes it to life expectancy.
What I am interested in is directly attaching an AC unit to a solar panel. Where I live it's generally only hot when it's sunny, so the AC would run for free.
Since the AC is one of the most expensive things to run it's win-win-win-win:
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