New Record For Solar Cell Power Efficiency 351
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%."
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.
Re:feasible (Score:5, Informative)
But in places like California, solar panels indeed pay for themselves
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)
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?
Re:feasible (Score:2, Informative)
About payback times (Score:3, Informative)
The calculation that produces a three year period says that you start saving money after three years. It assumes that you borrow money to buy the panels. After three years, the money you save on electricity is greater than the loan payments. The link below has a graph. You will notice that the savings take a big jump after twenty years. That's when the loan is paid back and you aren't making payments any more. So, using the link's assumptions, the payback on the investment is about twenty years.
http://www.ongrid.net/PVPayback.html [ongrid.net]
The point of the link is that, even if it takes a long time to pay for the system, you can still save money by going solar.
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.
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...
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.
Re:someone convince my local government (Score:1, Informative)
Re:What a pointless comparison (Score:3, Informative)
Seeing a car's power rated in terms of horsepower has always seemed somewhat excessive to me. For a long time, people used a single horse[1] to get around. They were quite slow for long distances, but could achieve something close to the legal speed limit for built-up areas. Since we're playing with absolutely ideal numbers, let's try another one; the car has zero mass.
According to Wikipedia, the Sun produces approximately 1KW of energy per square metre. Your 20 square metre car then has a 20kW energy output (around 27hp). How fast can this accelerate a human? Assume for now that a human weighs around 100Kg (most people weigh less, so this includes a small luggage allowance as well). One Watt is one Newton per second, and one Newton is the amount of energy required to accelerate one kilogram at one metre per second per second. Your 20 kW car can accelerate a 100kg person at 20,000 / 100 = 200 meters per second, per second. Since this is roughly 20g, you would probably not want to do that very often.
Now we have some absolute upper bounds on optimality, let's stray back slightly towards feasibility. At 40% efficiency, you get 80m/s/s. Still not bad. For reference, 0-60mph in five seconds requires just over five meters per second per second of acceleration. Of course, we're still assuming equatorial sunlight. Dropping the solar energy down to a more reasonable 50% gives us 40m/s/s. Our car still weighs nothing, however, so let's run this the other way; if we want 0-60 in 5 seconds, how much can our car weigh? The answer comes out at 700kg (800kg including passenger), which is not too bad; a quick google indicates that this is about half the mass of an average car.
It seems that a totally solar car is not completely beyond the realms of feasibility with current technology, but it will probably not be commercially viable for some time. For one thing, you're going to need a battery for when it's cloudy or night, which will drive up the mass very quickly.
[1] The original definition of a horsepower was for mine ponies, so a cart horse probably provided a few horsepower.
Re:feasible (Score:3, Informative)
Compare to direct solar heating, where damn near 100% of the energy you absorb gets transferred to the water. After all, the desired end product is heat, and it's trivial to convert 100% of any energy form into heat if you're patient enough.
=Smidge=
Re:What a pointless comparison (Score:3, Informative)
http://www.greencarcongress.com/2006/06/2006_sola
Solar drag racing (without batteries) can run the 1/4 kilometer (800 feet) in 57 seconds (using no batteries).
Well, the new record is 30 seconds for 820 feet, and 50 mph on finish - see http://users.applecapital.net/~jim/solardragrace.
And the future is shiny:
"As the race develops over time, solar dragsters may eventually exceed two horsepower"
Comment removed (Score:5, Informative)
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.
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,
Re:The real question.. (Score:3, Informative)
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!
Wow, how innaccurate (Score:3, Informative)
> produce the same amount of power as today's standard solar panels,
> which have an efficiency of about 17%."
The article being quoted clearly states that these cells require concentrated sunlight -- this is true of all thin-film high-TSE cells. So basically you can't mount them on the roof, you'll get no power at all.
Further, most solar panels get about 11% efficiency. There are ones that get into the 15-17% range, but these are much more expensive and see considerably less use as a result.
These new cells will be very useful for large-scale energy developments, like large solar farms in the desert. They are completely useless for rooftop deployment.
Maury
Re:hmmm. (Score:3, Informative)
2) Both sides are trying to muddy the waters. You don't hear "Everything will be fine" and you don't hear "We are all going to die" because there is some give and take with every publication.
3) Some people think we can't change the climate. But looking at the "Dust Bowl" in the US and "urban heat island effect" it's clear we can alter the local climate in significant ways.
4) It's generally accepted that increasing CO2 increases global temperature up to a point but we don't know what all the effects of increased global temperature are going to be. It's probably going to be expensive / destructive for low lieing costal cities but most of the temperature increase is going to occur in the north which might increase economic activity enough to help offset some of the damage.
IMO: I suspect in the long term (1000+ years) we will carefully control the worlds climate. Over the realy long term 10,000 - 1,000,000 years we may decide to alter the earths orbit and fine craft our heat output to deal with the amount of energy we are generating, but right now we don't have the tools or experience to deal with significant climate change. As with most significant changes large numbers of people are going to die and then the world will adjust and move on. It's not the end of the world just the end of our world as we know it.
Re:What a pointless comparison (Score:2, Informative)
This system is designed/manufactered by Webasto, I believe.
Germany is leading green (Score:2, Informative)
Germany lines all of its freeways w/ solar cells. That is making good use of otherwise wasted space.
I hope other countries (the US included) take some lessons from the Germans.
Roottop concentrators are being delivered (Score:3, Informative)
You won't be all that competitive is you are producing 11% efficient solar today. I think perhaps you are thinking that most solar panels already sold have a lower efficiency. One company is selling at $3.00/watt for lower efficency panels as compared with $4.20/watt for most. You have to compete on price to offset the higher installation costs of lower efficeincy panels.
--
Solar power you can afford: http://mdsolar.blogspot.com/2007/01/slashdot-user
Re:hmmm. (Score:3, Informative)
Here's one.
A rather one-sided presentation, I might add, but since you concede that this has already been countered by pointing out Albright's poor science and publishing his own website calling his boss's work a "myth", I don't need to get into details.
The same happened with two scientists in a Dutch government-run climatological research institute.
Really? Who? The only one I've heard of is Tennekes, and as far as I've ever been able to determine, he was not fired — he simply retired. He certainly has said nothing to the contrary himself; all the claims about him being fired can be traced back to an off-hand claim by Lindzen.
Who else were you thinking of?
That goes for both sides of the table, however most politicians, scientists and activists have far more to gain by a "let's impose controls" attitude than with a "nothing to see here, move along" attitude, the global warming camp is far more influential than the sceptics camp.
I am trying to imagine what scientists have to gain by imposing economic caps on carbon. I really hope you aren't going to drag up the "they can't get grant money otherwise" claim.
The current rate of warming is nothing exceptional, and might even be just a ripple in the trend.
On the contrary, there is no evidence for any rate of change as large as present, other than the abrupt D-O events associated with a collapse/restart of the thermohaline circulation.
The past has seen increases in temperature of higher rates and over a larger range.
You are obfuscating the issue. Remember that my point was this: the rate of warming is larger than the natural rate of cooling into an ice age. This is true. There have been other events, not associated with the ice age cycle, which have shown a rapid cooling. But this is irrelevant to either my point or yours (which was that we need the warming to offset imminent cooling). It's irrelevant because there is no such imminent cooling. Ironically, global warming itself is the only thing that could set off that kind of rapid cooling via a THC collapse right now, and even if it did, the amount of warming needed to trigger such a collapse would likely outweigh the resulting cooling itself.
That's also the pattern to most ice ages (and we're at the peak following a small one of a couple 100 years ago):
We are in an interglacial period, but it is dishonest to claim that we are at the "peak" of one, implying that it's all cooling from here on out; there is no evidence of this.
a slow decline in temperature, followed by a sharp ramp upwards.
The "sharp ramp upwards" during a deglaciation is still significantly slower than the current rate of warming, and is also irrelevant to your claims about imminent cooling.
Warming and cooling are natural trends, on which we have some (small influence).
The influence may be "small" compared to the total change involved in the ice age cycle, but that doesn't mean that the resulting impacts are negligible in any absolute sense.
We should be worried about the warming trend, but not exaggerate our supposed influence.
Nor should we minimize our actual influence.
Thart's like worrying about a small wave, while the normal tide raises and drops the water level by several meters.
That's also a dishonest analogy, since you are choosing as a basis for comparison something (a small wave) which demonstrably has no impact to society as a whole. You cannot demonstrate the same about current climate change. Furthermore, the fact that there have been large climate changes in the past is a red herring; sure, the Cretaceous was much warmer than today, but that doesn't mean that we'd prefer to live in that climate.
We have seen nothing yet.
Of course this is false; we have seen a warming trend, which appears inexplicable in terms o
Re:feasible (Score:3, Informative)
Along with that getting specialized home appliances can be cost effective; special extreme efficiency 24 volt DC refridgerator, for example. Reducing your install by 1 panel can save several thousand dollars easy.
Re:hmmm. (Score:1, Informative)
With the added difficulty of extracting the electric current from a spinning solar array, wouldn't it just be easier to put them on the ground, next to the wind turbines?
Re:feasible (Score:2, Informative)
Re:feasible (Score:3, Informative)
being in the process of doing a solar water heater myself, regardless the path you choose, you still have to run a pump, to even get close to a 14% solar direct to water heater efficiency.
IE you can place the storage tank above the heater, and pull your fresh water through the heater, and storage tank, allowing some thermal circulation, then your incoming water pressure to move things, but you surely won't be anywhere near even the 14% efficiency of a 14% EF PV panel (you will be much, much cheaper though)
in my system I have got a 65Watt 12VDC water pump circulating pump, and on order, 3*15Watt PV solar panels, a cheap charge controller [suburbia.com.au] and a solar panel. I am re-using my old water heater, and ordering a on-demand water heater to make up for only having room for a 20 gallon tank, when a 100 Gallon tank would be better sized.
even 100% DIY, many free parts, and Arizona sun. I am still going to be over $1000, to save maybe $200 a year in grid electric.
Re:feasible (Score:2, Informative)
given an estimated total build cost of $1.60/watt [wikipedia.org], that's roughly equivalent to nuclear [uic.com.au], but without all of the ongoing costs of large security forces, fuel cycles, decommissioning, and all of the nasty waste left over. let's not forget that uranium is getting more expensive and the spent fuel is piling up.
Now, i'm not anti-nuclear, in fact i think we should be building breeders as fast as wen can, but to discount wind, which is economically similar to nuclear in build cost per watt, is cheaper to maintain, and doesn't have a lot of the nasty side effects because of someone as subjective as "it's ugly".... seems silly to me>
how pretty are a bunch more nuclear reactors all over the place?
how much beautiful habitat will your kids miss out on because there's a power plant there?
how much land will be restricted from your babies eyes because of the countless acres around the waste storage facility that are cordoned off for national security?
wind turbines can be put right where power is needed if the location has a steady breeze, the're high enough off the ground that the land underneath is still usable for farming or.... whatever.
it's not nearly as ugly as it used to be, is it really worth discounting?
Re:Not too bad (Score:2, Informative)
Re:Efficieny of Trees (Score:3, Informative)