New Record For Solar Cell Power Efficiency

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%."

Comments

The real question..

[Enderandrew]

Yes, but will it run Linux?

Actually, while I'm glad they are making a more efficient solar panel, when will they make a cost-effecient solar panel for mass-adoption?

Re:The real question..

[Enderandrew]

The article is about solar panels. How is it off-topic to ask about solar panels?

Smog

[Rixel]

Hopefully, Solar Cell efficiency will keep ahead of smog cover in major cities.

Re:Smog

[R3d Jack]

Just move to a location upwind of all the pollution. Like, say, 50 miles west of Los Angeles.

Waiting

[Cassius Corodes]

Im waiting for them to reach above 100% efficiency before I'll buy

Re:Waiting

[Hoi Polloi]

Great, I'm stuck with the old 1st generation -135% efficiency solar cells. They are gas powered.

feasible

[farkus888]

a good grid tie system and these things will pay for themselves. I hope that panels of this efficiency are ready for public purchase when I am ready to be a homeowner. this is one of those things that makes economic and environmental sense and I hope it doesn't get stymied by people who are afraid to be "green" because they think it has to be more expensive.

Re:feasible

[Calinous]

The most efficient use of solar power is the water heating system. Solar panels are a distant second for now - as they are very costly for the power they can produce (we assume your house needs heating or hot water). Depending on conditions, wind power might be a cheaper overall choice than solar panels.
        But in places like California, solar panels indeed pay for themselves

Re:feasible

[evilviper]

The most efficient use of solar power is the water heating system.

I'm not too sure about that. How about a PV panel powering a ground-source heat pump? I'm willing to bet that would give you more hot water than direct solar heating, at least in most climates.

Re:feasible

[Calinous]

It might be so - however, I don't know the costs of a ground-source heat pump. Did any digging recently? Also, you can get hot water at a higher efficiency than electricity from solar power, and the costs of installations are lower to boot. What a solar water heating system can't give you (but a PV panel/ground pump could easily) is cooling

Re:feasible

[knarf]

That is why the two should be combined... Water-cooled Photovoltaic panels give the best of both worlds: cooler PV panels which are more effective PLUS warm/hot water for heating, hot water or - indirectly - cooling. The technology is out there. It is simple. It works. As to why is is not used that much yet? Good question.

A search on 'water cooled pv' 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...

Re:feasible

[Smidge204]

As per the summary, solar cells are 17% efficient. The efficiency of a heat pump will vary quite a bit depending on working temperatures, but the compressor motor will doubtfully be more than about 80% efficient (electrically). So overall, at best, 14% of the sunlight makes it into the hot water.

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:feasible

[xappax]

You deliberately buy things that aren't as cost-effective as other stuff, but that reduces CO2-emissions. Unfortunately your money aren't "lost", someone will get rich, such as the bank, or the company CEO, so even this method isn't 100% convincing to me.

Seems like if you deliberately spend money on things that are less polluting than the mainstream offerings, you're helping to make that industry more economically viable. For example: if you buy residential wind turbines, the company that makes them will profit. Yes, some of that money will probably be spent on things that cause pollution, like employee salaries or airline tickets, however it will also be spent on improving and marketing a product that can reduce pollution dramatically.

No institution or individual can ever have zero negative impact on the environment, but they can have a greater positive impact, so that their damage is offset overall. The question becomes, is a supposedly "green" institution really helping the environment more than they're hurting it? Some companies really are, and it's great to give them business, but some are just using environmental concerns as a marketing niche, and giving them money will do nothing but enrich them, and possibly allow them to create more pollution.

I agree with your general sentiment, though. The key is being critical and informed about where your money goes. When you spend money, it doesn't just disappear - it goes on to pay for things that may be destructive or immoral, and couldn't happen without your money. Or, it may go on to pay for things that are constructive and really awesome. Though the amount of money you spend may be similar, the difference between these transactions is vast when you consider the consequences.

Re:feasible

[Firethorn]

In such a setup, such as for a off-grid solar power house the cost benefits of using thermal solar for heating the water outweighs the loss of flexibility. Panels for solar water heating are generally at least an order of magnitude cheaper than solar electric panels. You simply oversize your water tank(and insulate it well) to last through a cloudy day/night.

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:feasible

[Talchas]

Sigh, standby yes (although I expect some would differ on "significant"), hibernate NO. Hibernate is off with the ram written to the hard drive.

Re:feasible

[xappax]

If it's profitable, it usually means their customers are making money by buying their power too. Which means that their customers now have more money to spend. See above.

I think you're presupposing that all possible things someone can spend money on have the same CO2-emission potential. $1 worth of burnt coal (in the form of electricity) produces X amount of CO2. If MiracleTurbine becomes successful, and I get to keep that dollar, I'm not necessarily going to spend it on something that also emits X CO2. In fact, it'd probably be pretty difficult to do worse than paying a company to burn up as much coal as possible for $1 and give me the energy produced. Buying gasoline could be as bad, maybe, but most alternative uses will not be, therefore there will be less "CO2 emissions-per-dollar-spent".

the most efficient way of reducing CO2-emissions is to not earn a living.

Actually, given the premise that consumption in general is the cause of CO2 emissions, the most efficient way of reducing emissions would be to earn a living and then not spend any of it. After all, if you refuse to work, your potential employer will just take that money and do something else with it, right? Something that will probably contribute to CO2 emissions. So the most efficient thing to do would be to earn a lot of money and then sit on it - literally, take it out of the bank (banks invest your money in CO2 emitting companies/governments) and put it under your bed, or just destroy it entirely. This is the only way you can really be sure it won't be used for CO2-emitting consumption, and the more money you "take out of circulation" this way, the less consumption is possible.

The problem with this strategy is, unfortunately, that the government creates as much money as they want. If money is taken out of circulation, they can just add more in to replace it and keep the cycle of consumption going. Really, money is only effective when spent, which brings me back to my original point. Strategically spending money (give money only to institutions which are helping to reduce CO2 emissions, boycott outright those which increase it) is possible, and unfortunately in a capitalist economy, probably the best available way to create a net positive impact on CO2 emissions.

Re:feasible

[Dare nMc]

Not only is the theoretical maximum efficiency of blackbody air to water (with solar deflectors added in) max out to around 60%, so not much improvement needed to be equal. (since this 40%+ efficiency needs deflector as well)

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 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

[undercanopy]

for reference, i'm referring to the newer, more sleekly designed turbines than the older scaffold-looking eyesores (i'll agree with you there)

given an estimated total build cost of $1.60/watt, that's roughly equivalent to nuclear, 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?

hmmm.

[apodyopsis]

I'm interested in solar power as a means of lowering the fossil dependency - but there are other, better means of doing so. The CE manufacturers need to meet them half way and mandate more efficient devices that consume less power and bring back the humble ON/OFF switch that actually did turn off the power. Is it that hard to walk to the TV? And, of course, wind and tidal need to be followed up.

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:hmmm.

[NeilTheStupidHead]

Everybody wants wind power (but not in their back yard) That's one thing that I've never understood. I used to live about an hour's drive from a wind turbine and drove by it several times a day. I could never wait to drive by because I loved the sight. My new home is very windy and could benefit greatly from wind power. I simply cannot fathom the resistance to wind turbines.

One thing I have always wondered though: given the fairly large surface area of the turbine blades, would it be possible to add a photosensitive material and pull a bit of power from the sun too? Probably not terribly practical at the moment, but I seem to recall reading, probably on /., about a paint on solar panel.

Re:hmmm.

[Calinous]

The wind turbines convert some of the wind power in electricity, some of it goes in vortexes, and some goes into sound. A small wind turbine will spin at higher rpm in wind, and the noise might become unpleasant.
      As for solar power from blades' surface - the tower where the turbine is seated has more surface area than the blades, extra mass is not usually a problem, and you have a sun-facing side - the blades don't always have a sun-facing side (so you'll need to put panels on both sides), the shape of the blades is critical for efficiency, and mass in a fast rotating, very long blade is always a problem

Re:hmmm.

[pzs]

What really depresses me is seeing the general public in interview and their complacency and dismissiveness about global climate change. People's sense of entitlement is astonishing: "I work hard so I have the right to a low-cost long-haul flight," even if we've done without that "right" for thousands of years and those flights are ultimately destroying the planet.

There is also the huge number of people who believe that the consensus of thousands of scientists on climate change is a "global conspiracy" and their fear that it may eventually mean, shock horror, more taxes. This from people who will never know hunger, get free education and health care and live in the extreme safety and tranquiltiy of a developed nation. If you think I'm making this up, try looking at the "Have Your Say" debates on the BBC News web page.

It really is enough to make me think this is a good idea.

Peter

Re:hmmm.

[hcdejong]

My parents live in an area that has lots of wind turbines. A few years ago, many of these were small, high-rpm turbines that were clearly audible from hundreds of meters away. Sitting in the back yard, you always had this droning noise in the background, this could be very annoying.
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:hmmm.

[monk.e.boy]

My friend lives about a mile away from a small wind farm. I is very noisy, it sounds like cars on a freeway, but far too regular. Almost like a loud heart beat. And when the sun catches the blades you get a nice strobe effect which sends you fucking crazy after an hour or so.

My friend is selling up.

I can't wait, we never visit him any more. His house sucks.

Wind farms are ok - so long as they aren't in your back yard. Solar and Nuke is the real future.

monk.e.boy

PS check my .sig for Open Source Flash Charts (bar, line, area and pie)

Re:hmmm.

[lauwersw]

There's another idea about this gaining attention. Suppose people do care and start conserving energy. They pay less for their energy bill, so that means they own more money. What do they do with this money? Spend it on other things of course! So that means other people are earning more money, for example in other parts of the world that are currently using less energy. What will they do with this extra money? Yes, spend it and in that process use more energy than they would have before!

Net result? 0

Maybe this is just a general law in nature: a species will use up all resources it can find. The only real solution would be a real clean source of energy. Your alternative would work too, but is way less attractive ;-)

Re:hmmm.

[JaredOfEuropa]

There is also the huge number of people who believe that the consensus of thousands of scientists on climate change is a "global conspiracy" and their fear that it may eventually mean, shock horror, more taxes.

This believe is partly justified. The conspiracy isn't by the scientists, and isn't a global conspiracy either, but the climate scare has given the meddlers of any political stripe the perfect pretext to push their own agendas. The climate debate has been thoroughly politicised, at the expense of proper science. That does not mean that all conclusions are incorrect or made up, but very often peer reviews are sorely lacking, and many reports have had chapters and sections stricken in the final draft, because those sections could cast doubt on the severity or existence of human impact on the climate. In many cases scientists voicing such doubts have not been gainsaid, but fired from "scientific" institutions. Because a widespread doubt in our impact on the climate would spoil the party for the meddlesome politicians. The political stakes are huge, perhaps the largest of any issue in our history.

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.

Re:hmmm.

[russ1337]

They pay less for their energy bill, so that means they own more money....Spend it on other things and in that process use more energy than they would have before....Net result? 0

I didn't realize my energy company was denying me spendable income with the intention of saving the planet. Here I thought they were just squeezing every cent from their customers for profits!

Re:hmmm.

[Anonymous Coward]

The hooker herself can be inherently bad for the environment unless you find an off-the-grid vegan hooker. But by that point, she's so skinny and annoyingly opinionated that you really wouldn't want to touch her with a 20 foot pole. Besides, those emo frame glasses were made from petroleum.

Re:hmmm.

[pjabardo]

These are *VERY* wise words!

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".

Re:hmmm.

[tehcyder]

I simply cannot fathom the resistance to wind turbines.

They're planning on one near where I live, and the most amusing objection/worry is that one of the blades might fly off and decapitate a swathe of children playing in their school a few hundred yeards away...

Re:hmmm.

[OldBus]

I simply cannot fathom the resistance to wind turbines

It's probably drag and friction...

Re:hmmm.

[Retric]

1) Ice ages are somewhat random events so saying 10,000 years we will be in an ice age is silly it may have already happened or yet to start. Looking back several million years ices ages have no where near the consistency as the seasons. They don't all get as cold they don't last the same amount of time and they don't occur on a regular basis.

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:hmmm.

[RocketScientist]

I think you have a valid point but you need to look at why this happened.

Among the general public, basically they've had the "global warming" concept beat into their heads, but they're watching the people doing it fly around the world in private jets and live in houses with 4K/month electricity bills.

Among the geek skeptics, like myself, what I see is not science, it's religion. It's "we've solved this problem, we know it's happening, so NO MORE DEBATE ABOUT IT!!!!". That's not science. We're still debating gravity, we're still debating inertia, we're debating light as a particle or wave. That's science. The "no more debate, no more discussion, this is happening and anyone who doesn't believe must be shunned" vibe from most environmentalists is simply religion, not science. Not that the other side's better, buying off scientists and spinning science to meet a political agenda funded by energy companies. But therein lies the problem: this is a political issue, not a scientific one.

My main problem is that we're extrapolating a 4 billion year old climate with about 150 years of directly observed but partial data and 30 years of directly observed global data. The tree ring studies originally done were riddled with accounting problems and were, very likely, fraudulent, and the remaining indirect methods seem to point in many different directions. Further complicating the issue is the ad hominem attacks every time a study comes out that supports either side. If I was an environmental scientist at this point, and no matter what I published I risked physical threats to my security, I'd probably find another line of work. That's the position we've put these people in. They can't publish science anymore, everything they publish is a religious tract, hoping to sway one camp or the other to provide them protection and cash so they can continue their work.

Back on topic: Solar cells are nice, but once you factor in the environmental cost of production they're not efficient. Greenhouse gases are not the only pollutants, they're just the fashionable ones to bitch about right now. Arsenic, volatile and carcinogenic organics, acids, and heavy metals are created/liberated as a byproduct of solar cell production. The problems of these pollutants haven't been solved, they've just taken a back seat to greenhouse gases. When you consider the immediate problem of groundwater pollution against a backdrop of a possible global warming problem, solar cells seem to sell out the immediate problem in favor of the long term one. We've got the technologies to solve both problems with a minimum in absolute terms of toxic byproducts, but ironically the environmental movement hates it.

go nukes.

We have the solution to the problem, we just need the environmental movement in this western world to actually go through the enlightenment and discover that maybe, just maybe, science might fix this problem instead of religion.

Re:hmmm.

[Sandbags]

We don't even need a true power on off switch that has to be flipped manually. What we need is a remote power switch that cuts main power, and a small, rechargeable battery cell that can respond to the remote and re-activate main power. A tiny battery and a capacitor to have enough juice to throw a 2.5 volt magnetic switch would add about $1 in manufacturing costs to home theater devices, but save dozens per year in electric fees per home for "trickle" devices. All network devices should support Wake on LAN, but unfortunately, most don't (or do, but people don't know what that means or how to use it).

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

Re:hmmm.

[Ambitwistor]

That does not mean that all conclusions are incorrect or made up, but very often peer reviews are sorely lacking, The actual scientific literature published in journals is peer reviewed.

and many reports have had chapters and sections stricken in the final draft, because those sections could cast doubt on the severity or existence of human impact on the climate. In many cases scientists voicing such doubts have not been gainsaid, but fired from "scientific" institutions. Please, give examples.

And while you've raised the issue, shall we discuss political meddling in the opposite direction (cough EPA report cough)?

Why are long term trends not taken into account in these reports, for example. They look at century time scales, but not longer, because (despite what you say) predictions are very hard to do for longer timescales, especially given the uncertainty in what humans will be doing in terms of atmospheric emissions and land use changes. Remember, climate physics is not the only input into climate prediction; you need projections of human activity as well. (See here.)

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)... It is far from established when the next ice age cycle is going to start, and there are some who claim that due to patterns in orbital dynamics, the current interglacial could be exceptionally long (as long as 50,000 years). (See here.)

Perhaps that is why the IPCC report does not look any further than the year 2100 Perhaps it is, as I said, hard to project much more than a century or two in advance.

the scary hockeystick curve will flatten out after that year, and if you look even further it will drop The current rate of warming far exceeds the natural rate of cooling during glaciation. That rate of warming will eventually level off, but it's not going to be outweighed by glaciation any time in the next few centuries.

It is true that eventually we will enter a new ice age, regardless of global warming, but no one is "ignoring" this fact. It's just farther off into the future; right now, the warming is what we have to deal with. If warming is a problem, you can't just ignore it because someday it will be cooler.

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. If that turns out to be the case, it's better to release the CO2 then, rather than now, when we don't need it. As we have seen already, it's far easier to raise the temperature quickly than it is to cool it, having to do with the ease in emitting CO2 as a byproduct of civilization and with the long residence time of CO2 in the atmosphere.

Re:hmmm.

[JaredOfEuropa]

Please, give examples.

Here's one. The same happened with two scientists in a Dutch government-run climatological research institute. I'm sure you can find others, and I am also sure each of these examples can (and have) been countered by arguments of these scientists being fired for bad science or using "improper channels" to release their counter-claims.

And while you've raised the issue, shall we discuss political meddling in the opposite direction (cough EPA report cough)?

My point is that the entire climate debate is no longer about science, but about politics. 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.

The current rate of warming far exceeds the natural rate of cooling during glaciation.

The current rate of warming is nothing exceptional, and might even be just a ripple in the trend. The past has seen increases in temperature of higher rates and over a larger range. 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): a slow decline in temperature, followed by a sharp ramp upwards.

It is true that eventually we will enter a new ice age, regardless of global warming, but no one is "ignoring" this fact. It's just farther off into the future; right now, the warming is what we have to deal with. If warming is a problem, you can't just ignore it because someday it will be cooler.

Warming and cooling are natural trends, on which we have some (small influence). We should be worried about the warming trend, but not exaggerate our supposed influence. Thart's like worrying about a small wave, while the normal tide raises and drops the water level by several meters.

As we have seen already, it's far easier to raise the temperature quickly than it is to cool it, having to do with the ease in emitting CO2 as a byproduct of civilization and with the long residence time of CO2 in the atmosphere.

We have seen nothing yet. The current increase in temperature might be a ripple in the trend, it fits the trend itself, and it might also be caused or aggravated by human influence. But in the history of the earth it is most certainly not anything out of the ordinary.

Re:hmmm.

[Ambitwistor]

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:hmmm.

[CommieLib]

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.

I've got to disagree with you from both sides of the political aisle. I will argue that we cannot make accurate climate predictions (at least within the range that is relevant to the anthroprogenic global warming debate) because we have utterly failed to do so in the past. That data that the IPCC use show no warming after 1999, which doesn't even fit the past of the model, let alone the future.

I think really what the whole problem is with the debate is that there's a huge difference between the approaches of the typical person and the scientist to uncertainty. A scientist eats, drinks and bathes in uncertainty, and is comfortable with saying, "Gee, we just don't know. Maybe we'll know more in the future, but this is our best understanding currently, and it is almost certainly at least partially wrong." The typical person deals with decisions made on imperfect information in their daily life, and regards uncertainty as incompletion, or at worst, weakness. That's why we have people who believe in UFO's, ghosts, or fricking Sasquatch rather than saying, "I just don't know what the hell that was. I probably never will."

As the previous poster pointed out, the whole debate is INCREDIBLY useful to authoritarians, as is any crisis which justifies sweeping powers and changes to society.

Solar cell? Pfftt.....

[ihaveamo]

I'm working on a lunar cell at the moment... the other 50% of a day is totally untapped!!

What a pointless comparison

[suv4x4]

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%.

Let me guess: you'll leave how your roof empty to produce the same electricity, or take the whole roof to produce more than twice the electricity. Hard dilemma...

At this point solar energy seems inevitable in our future. Not long from now we'll have more efficient electric motors and even more efficient solar cells, so that would make it a viable backup to a car battery charge and mean you can drive for days and days at long distance without recharging.

The big money now will go to those people who manage to best make use of our existing infrastructure and our new technologies (stellar examples include Toyota's hybrids... imagine if that electric motor they use also has few solar panels to help it in the next models).

Re:What a pointless comparison

[Calinous]

Assuming your car has 20 square meters of surface, all of it oriented towards the sun. In Ecuador. With 100% efficient solar panels.
      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:What a pointless comparison

[tekrat]

So, run this by me again;...

Consider that, aside from police cars and taxis, most cars spend most of the time PARKED, either in a parking lot at work, or a driveway at home. The average car's lifespan is mostly spent at rest, with about a 1/2 hr drive to work and a 1/2 hr drive home.

Why is it NOT prudent to build a solar panel into the roof and/or engine hood to help recharge the batteries while the damn thing spends 8 hrs per day parked in the sunshine?

Hell, if we could take the heat that builds up inside the car on a hot summer day and convert that into electricity, I bet I could drive home just on that!

TTYL
Brian C.

Re:What a pointless comparison

[TheRaven64]

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:What a pointless comparison

[Calinous]

Let's see what is possible now:
http://www.greencarcongress.com/2006/06/2006_solar _drag.html

      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.h tm

      And the future is shiny:
"As the race develops over time, solar dragsters may eventually exceed two horsepower"

Re:What a pointless comparison

[Rocketship Underpant]

"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?"

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.

Re:What a pointless comparison

[FJR1300 Rider]

Some VW/Audi models have a "solar sunroof", which is nothing more than a small solar panel mounted on the sunroof. It is used mainly to produce energy to keep the AC fans working even when the engine is shut off (when there's sunlight, at least), to keep the interior of the car cooler than it would normally be if it were parked in the sun. Since the car interior is, on average, 20 degrees celsius cooler, the AC will have a much easier task of cooling the cabin to the desired value, thus saving a little bit of fuel. Pretty neat.

This system is designed/manufactered by Webasto, I believe.

How much power?

[DoofusOfDeath]

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%."

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?

[Calinous]

Peak solar power is around 750W per square meter of installation. With those new panels, you could get - let's say - 1000W per 4 square meters (40 square feet).
      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)

someone convince my local government

[Shivetya]

that renewable sources of energy are a good thing.

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...

[Anonymous Coward]

...than price per watt. We got plenty of space we can cover with solar cells so it's not important that they are extremely efficient, just cheap enough so it doesn't cost much to cover large areas.

Another kind of efficiency

[fringd]

The real problem with solar power is not getting more watts per square inch; it's getting more watts per dollar. From what I hear, high grade silicon is prohibitively expensive. It takes more than 3 years to pay back your monetary investment. This information is probably based upon old panels though.

These new panels may produce twice the energy, but is there any chance that they cost less than twice the dollars? What is the limiting factor in solar panel costs?

I've heard that some people are working on polymer solar panels, this would seem to deal with the dependence on expensive silicon...

Re:Another kind of efficiency

[dwandy]

It takes more than 3 years to pay back your monetary investment.

"Three years" should not be a 'too long' perdiod to re-coup your investment.

• That's less than 4% of an average lifetime.
• I'd take an investment that was guaranteed to pay back 100% every three years.

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:

• I can run it guilt-free
• It runs whenever it's hot
• I don't need the other infrastructure
• I will still pay for the panel in a relatively short time.

Re:Another kind of efficiency

[dbIII]

If you are running AC then solar thermal in one of many forms is a better idea - use that heat to move heat around instead of making electricity and turn it back into heat to move heat around. Then you use your panel for your electronic stuff runing on DC - suddenly you don't need a very big panel anymore.

About payback times

[Anonymous Coward]

It probably takes a lot more than three years to pay back the investment. A three year payback would be astounding. If that were the case, you could shut down all the existing power plants and run the country just on solar. OK, that's a bit exagerated because solar doesn't make power all the time. Even so, a three year payback would see a dramatic increase in solar use.

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

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.

Spot on.

[ushering05401]

"The CE manufacturers need to meet them half way and mandate more efficient devices that consume less power and bring back the humble ON/OFF switch that actually did turn off the power."

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:Spot on.

[JaredOfEuropa]

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.

It goes to heat production, mostly. However I prefer a step forward rather than taking a step back by having to turn everything off. It is possible to make equipment have a minimal power consumption on standby, by only running a small circuit that looks for the "On" button being pressed on the device. A lot depend on how you power this circuit... a transformer is a notoriously bad way of doing it.
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,

Massive scale solar farming

[Linker3000]

The development of solar power will go a good way to lowering our dependency on fossil fuels, but to be practical we need to deploy the cells in a massive scale - I'm thinking thousands of square miles of solar farms - so what we really need is a relatively flat landscape in a location with significant sunshine levels. It would also be ideal if the region could provide the raw materials for the manufacture of the cells to save in transportation costs, but to be perfect the region would also have an abundant supply of fossil fuels to power the manufacturing plants until such time as construction was complete.

In summary, the ideal location would have:

Sun
Sand
Oil

You see what I did there!?

fail

[jovius]

Yes, this is great, but solar power will eventually fail completely, and there are no guarantees for long-term investments beyond five billion years from now.

Economically feasible?

[Anonymous Coward]

What matters to me: Do those new cells finally "produce" more energy during their life than they required during manufactoring?

Re:Economically feasible?

[Squirmy McPhee]

What matters to me: Do those new cells finally "produce" more energy during their life than they required during manufactoring?

What do you mean "finally"? They always have, though nowadays they recover the energy used in their production much faster than they used to. A few years to recovery is typical, and you really have to be trying to make it more than a decade. By contrast, the solar panels themselves are waranteed for 20+ years and thought to have useful lifetimes of 30+ years.

Comment removed

[account_deleted]

Comment removed based on user account deletion

Concentration Is Good

[Doc Ruby]

Concentration of a larger solar input area onto a smaller solar cell is nearly always better than straight 1:1 reception. The efficiency goes up with these materials, which of course is good.

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.

Not too bad

[Gr8Apes]

I looked into this recently. Installing a ground based heat pump instead of a regular air conditioner would have been around $6K (instead of $2K for the AC). Note that this was for an old style 12 SEER AC unit that's no longer available against a 25+ SEER heat pump (get added bonus of generating heat). AC units have almost doubled in cost, and now are about $4500 installed (new US regulations require higher SEER units).

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:Not too bad

[Gr8Apes]

Actually, there's another issue with solar hot-water systems: home owners associations. In my particular case, I can't put such a system on the preferred side of the roof because it'd be visible from the street (my house faces SSW). There's also the issue of performance, although I've not looked into this in the past 8 years so I'm not up on any improvements.

Re:why don't they...

[zqwerty]

Its 20 years since I looked into solar cells in my engineering job, but the figure quoted above must be close to theoretical maximum because solar cells amount to a forward biased diode and can never get to 50% efficiency, they also have poor temperature performance which falls off rapidly as they get hotter, so enclosing them and reflecting more sunlight onto them is exactly the wrong thing to do, they run most efficiently when cool. As said in this thread the big problem is cost and having to store the electricity when the sun is not around at night.

Buy more oil not solar.

[bri_eh]

The power of Bush compels you! The power of Bush compels you! But seriously, transfer 1/16 of the money from the oil wars to research on making more efficient and cheaper solar cells and we will will have a energy independent North America and far less air pollution before the 2050 point of no return.

Being done in New Mexico

[mdsolar]

I razzed New Mexico Governor Bill Richardson on my blog yesterday saying he is trying to keep the southerneastern US off solar so he can build a huge New Mexican Solar Power Monopoly to supply them: http://mdsolar.blogspot.com/2007/07/new-mexicans-c onspire.html(tinfoil hat warning). One of the projects linked there aims to do just this, havesting the heat generated at the panels for building heating. Engulf and Devour, that's his motto.
--
Register your home for solar power; fixed competitive rates for up to 25 years: http://mdsolar.blogspot.com/2007/01/slashdot-users -selling-solar.html

Put some things into perspective

[ilovethesun]

Hi,

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

[Maury Markowitz]

> 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%."

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

Germany is leading green

[IwantToKeepAnon]

I saw a Nova (IIRC) where Germany is subsidising individuals to put up solar cells. Farmers are covering entire fields with them. They have a contract so that they are garunteed to recoup expenses and make a profit.

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

[mdsolar]

In fact, roof top concentrators look quite practical: http://www.technologyreview.com/Energy/18718/. I wish the original article had given a diagram of how their system is laidout, but it definitely mentioned rooftop use.

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-users -selling-solar.html

FINALLY SOME GENUINELY GOOD NEWS

[tjstork]

I've got my black colored glasses on, but to me it seems like almost every headline lately is either bad news for some group, or at least provokes a political brawl. But finally, after what seems like a brutal decade, there's been a bit of good news for Team USA. GM and Ford are both making money, and now someone has made a real advance in solar cell efficiency. As someone who lives in Delaware, and has seen banks slash their staff and Chrysler announce the closure of a key auto plant, the prospect of any industrial expansion is a welcome bonus.

Let's say something political, now. Let's hope that the Government can come together with the kind of tax incentives they are waiving around for Ethanol and Oil production to help building owners migrate to solar cells. I think we've beaten the crap out of each other enough debating energy independence and its just time to get rolling.

Duh!

[Anonymous Coward]

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%

It makes no difference to me whether they cover the entire roof, or just half. Space on my roof is free. The important question is, which solution is cheaper? I wish they would give us cost efficiency, as in dollars per watt. Watts per square inch is only important when land or space is terribly expensive.

High tech one offs

[Danathar]

I think most people would be surprised what can be created with technology when you only have to make a few of them. It's the mass manufacture of "scifi" like devices that is HARD.

If I wanted to create super sci-fi stuff for my spy that's not so hard, custom made stuff with lots of money behind it can do amazing things.

I'm really hoping that their method is mass manufacturable.

Smug

[smaddox]

I'd be more worried about Smug. With all these people buying hybrids, Smug levels are on a record high!

Re:Efficieny of Trees

[ChrisMaple]

Vegetation varies greatly. I've seen figures as high as 10% for high yield plants. Just to guess, a fast growing healthy tree might be 1%, an old hardwood 0.1% or less. Something like a bristlecone pine would be very poor, indeed. Where I live (southern New Hampshire) the growing season is only 5 months, so more than half the year is completely lost.