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Solar Cell Achieves 40% Efficiency

kdawson posted more than 7 years ago | from the too-cheap-to-meter dept.

Power 632

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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transport losses? (5, Insightful)

toQDuj (806112) | more than 7 years ago | (#17125638)

yes, a few hundred miles in the american southwest would do it (anyone objecting to using Texas?), but only if the entire world lived in the american southwest. As it is, energy losses due to transportation are quite significant and hinder an all-out world power source plan.

B.

Re:transport losses? (3, Insightful)

dew-genen-ny (617738) | more than 7 years ago | (#17125662)

When you say energy losses due to transportation, are you just talking about transmission over wires?

How about conversion to something like hydrogen?

There are lots of desert areas that I'm sure could be used for energy generation, at least it would be better than polluting our way to global death....

Re:transport losses? (5, Insightful)

jtorkbob (885054) | more than 7 years ago | (#17125852)

Hydrogen conversion has its own inefficiency, so that's out.

That statistic is simply an illustration in any case. Obviously there are some other places in the world where such installations could be put; perhaps some less sunny ones would require more space to reach equivalent capacity.

In any case, I think that a 100% solar earth is unlikely:

* Much of the time it is night, and storing that much juice in batteries is impractical. Things like hydroelectric storage and thermal solar plants could help with this problem, but its a whole different research issue.
* In the event of, say, a major volcanic eruption or meteor impact, world power production would plummet. That could be the least of our worries.

Solar and wind are like the icing on the clean power cake. They are great for the role they serve, but you can't have them for dinner without getting a stomach ache.

Re:transport losses? (3, Insightful)

poopdeville (841677) | more than 7 years ago | (#17126034)

I think the best use for this technology would be to put it on every roof in in America (and Europe and eventually the world), and use nuclear power as a method to buffer against periods of low sunlight.

While the major volcano/meteor event you mentioned could deplete the nuclear buffer, it would do that (and worse) now.

At the very least, considering the effects on the economy that nearly free energy would have, we could build enough nuclear power plants to completely handle our energy needs in case such an unfortunate turn of events occured. Hell, we could sell of the surplus nuclear energy to subsidize projects like the complete mechanization of food production, -- obviously using our nearly free energy. Or just lower taxes (though I would prefer the former)

Re:transport losses? (5, Funny)

Anonymous Coward | more than 7 years ago | (#17126072)

Mod parent up. He clearly knows how to achieve the technological utopia we all long for.

Re:transport losses? (2, Insightful)

mubes (115026) | more than 7 years ago | (#17126110)

With the exception of nuclear power we already have a 100% solar earth to all intents and purposes. It's just the conversion techniques that vary.

Re:transport losses? (1, Insightful)

Anonymous Coward | more than 7 years ago | (#17125700)

As it is, energy losses due to transportation are quite significant and hinder an all-out world power source plan.


Also the fact that USA is hostile to the rest of the world and extremely selfish, means no other country could trust it as a source of energy anyway. Example about the area was there just to illustrate, not as a concrete suggestion how energy needs of the world should be solved. There might be even better places in Sahara, but we'd still face the problems of moving the energy efficiently. Luckily, solar energy is quite easy to decentralize, however not suitable for every country.

Re:transport losses? (1)

Jugalator (259273) | more than 7 years ago | (#17125718)

Yes, so they could use a much smaller area for just the US instead, and have the cells a bit better distributed. I don't see how that would be a bad thing though. Sure, perhaps for underdeveloped countries (who're going to spend all the money to build for them?), but not really elsewhere. 40% efficiency would have enormous benefits, let's hope we get their in production cells soon enough.

Re:transport losses? (1)

Shados (741919) | more than 7 years ago | (#17125862)

Just having it as standard on the roof of 80% of the houses of the metropolitan areas of the world probably would cover a large chunk of the energy requirements. Then build a couple of "solar plants" here and there over the world to sell it like we do with hydro-electric dens right now. Then finish it all up with a few hydrogen or whatever "factories" that use this as power, and you should cover 95%+ of energy needs of the world. Because no solution fits everything, cover the last 5% with the good old fashionned ways (dens, fossil fuel, etc). Even if this is just a pipe dream... if we could only lower fossil fuel use by, let say, 5-10%, that would already have extreme benifits.

Re:transport losses? (0)

Anonymous Coward | more than 7 years ago | (#17125976)

Even if this is just a pipe dream

It is. You haven't factored in the most important part. What is the cost per kilowatt-hour? I don't care if these solar cells get 99% efficiency if they can't produce electricity for less than $0.07/Kwh. Additionally, you should note that these solar cells won't be useful for cars, trucks, or ships (60% of worldwide energy usage) so you won't be able to drop 95% of the energy needs of the world unless hydrogen produced from these solar cells is also cheaper than oil.

Re:transport losses? (0)

Anonymous Coward | more than 7 years ago | (#17125728)

it's about time to utilize your house roof!!

Re:transport losses? (1)

krotkruton (967718) | more than 7 years ago | (#17125742)

Nobody said that the area couldn't be split up and put in different places, but you make a good point anyway.

Also (not contrary to anything you were saying), I did not read the article, but the summary said 265 miles on a side, which turns out to be 70,225 square miles. Texas is 268,581 square miles [texasalmanac.com]. A solar array that large would take up a little over 26% of Texas. When put in that perspective, that's a huge mass of land. Using "265 on a side" just doesn't do the size justice.

Re:transport losses? (3, Funny)

Anonymous Coward | more than 7 years ago | (#17125858)

Great. You've been so brainwashed by the media measuring in Libraries of Congress or Size of Texas that now you are forced to convert into those units to understand a size.

Re:transport losses? (1)

Gotta ask yourself.. (977664) | more than 7 years ago | (#17125762)

But why would you want to have only one energy source anyway? Obviously the "one-spot-on-earth" example was just that, an example, but in a real situation it would make far more sense for each country to have its own solar cells to draw energy from, or at least have them more evenly spread across the globe, both for politica, economical and logistic reasons.

Re:transport losses? (2, Insightful)

nicholas. (98928) | more than 7 years ago | (#17125796)

And yet somehow we have no problems tranporting oil to non-oil producing regions. A huge solar farm could produce massive amounts of hydrogen. And hydrogen transports just as easily as oil via the same infrastruture. Cheap, unlimited, nearly clean energy and all we have to do is build it. I bet (no figures nor money to back me up) that we could have built several solar farms for the cost of one war in Iraq --not that I'm getting the two issues confused ; )

Re:transport losses? (5, Informative)

Anonymous Coward | more than 7 years ago | (#17125884)

And hydrogen transports just as easily as oil via the same infrastruture.

Bzzt! Wrong answer. Hydrogen requires a completely different infrastructure that has never been massively developed. Transporting hydrogen trapped in a hydrocarbon is feasible and could use the same infrastructure, but hydrogen itself is a much more complicated issue. You either need to cryogenic cooling or you need to build infrastructure that has low hydrogen diffusion and low hydrogen embrittlement (and probably very high pressure to move a significant energy density of hydrogen around if you go the gaseous path). People who want hydrogen for various industries tend to steam reform it from hydrocarbons instead of using this oil infrastructure you think can transport hydrogen.

Re:transport losses? (1)

SnowZero (92219) | more than 7 years ago | (#17125974)

At $50 a square foot (the current cost of a 25%-efficient cell), a 265-mile square of solar panels would cost $98 trillion dollars. That's quite a bit more than fighting even an expensive war. We will still need a few more breakthroughs for solar to be practical. With a 5x reduction in price, for example, you'd probably start to see it on a lot of buildings.

NO WAR FOR SILICON!

Re:transport losses? (1)

krotkruton (967718) | more than 7 years ago | (#17126064)

Minor correction: We will still need a few more breakthroughs for large-scale solar to be practical.

Re:transport losses? (2, Informative)

poopdeville (841677) | more than 7 years ago | (#17126106)

And yet somehow we have no problems tranporting oil to non-oil producing regions.

We don't?

Wait, we do. And that's the prime economic reason developing alternative energy strategies is in the US's (and everyone else's) best interests, despite our reliance on our current profits in the energy market.

Well you don't need it all in one place... (0)

Anonymous Coward | more than 7 years ago | (#17125816)

Solar power isn't a total solution, but if this is true with 40% efficiency and if these things can be done economicly then fuck it's a pretty damn good first step.

Screw transmission loss. I want my roof to be solar panels... Screw asphalt shingles.

Seriously. What is the transmission losses of a few meters?

Everybody could be their own power station then. Then it woudl only have to augmented by centralized power plants. Combination of Nuclear, existing hydroeletric, and petrolium plants.. all based on the geographical realities, with decentralized solar generation buildings would help a lot.

Maybe even make hydrogen power practical for automobiles and other devices. (thus reducing the dependance on toxic batteries)

This is pretty kick-ass if it all works out.

Re:transport losses? (0)

Anonymous Coward | more than 7 years ago | (#17125946)

The map on the link is very interesting. Contrast it with this map of population density [usda.gov], notice how population density is almost inversely correlated with total solar irradiance (except for India and some parts of Africa). Also remember that the resistance of a wire increases with its length. This means that, barring millions of miles of superconducting cable, the transmission losses incurred by transferring PV generated power from sunny areas to populated areas will most likely swamp any advantage (other than generally reliable sunlight presence) of locating PV plants in sunny areas.

Additionally, consider that the population of the Earth is likely to grow, a little, and become more developed, a lot, which will increase energy needs by perhaps a full order of magnitude. The expected population of the Earth in 2100 using energy at the rate of the developed world corresponds to something like 100 TW continuous power usage by the world. Factoring all that in (even using the 40% uber-efficient PV cells), we would have to dedicate something like the equivalent of the area of India to PV arrays. And India is not such a small place...

Cost is the issue (1, Insightful)

bastiaannaber (701867) | more than 7 years ago | (#17125642)

Very nice, but I'd rather see a reduction in cost per watt than an increase in efficiency. It's not like there isn't enough space for for solar cells. Most of the deserts are rather empty. Only if the price per watt drops significantly will we see these things filling up deserts.

Re:Cost is the issue (4, Informative)

GreyPoopon (411036) | more than 7 years ago | (#17125674)

Very nice, but I'd rather see a reduction in cost per watt than an increase in efficiency.
By reducing the number of solar collectors needed or the area that needs to be covered, the installation costs are significantly reduced. The article indicates that this new technology could yield systems with installed costs of as little as $3 per watt.

Re:Cost is the issue (5, Informative)

dch24 (904899) | more than 7 years ago | (#17125838)

In addition, 40.7% is just a bump up from 39% [boeing.com], which (apparently) Spectrolab has been achieving for the better part of the year. They may be very close to high-volume production. Direct photovoltaic solar generation is an immediate revenue source, but solar energy can be directly applied for other processes, the most notable being desalination [wikipedia.org].

Re:Cost is the issue (0)

Anonymous Coward | more than 7 years ago | (#17125682)

if you can increase the efficiency and keep the price the same or only slightly higher, then there is your price drop

Re:Cost is the issue (2, Informative)

rgravina (520410) | more than 7 years ago | (#17125696)

I'd rather see a reduction in cost per watt than an increase in efficiency

Aren't the two related?

Also, FTFA:
This breakthrough may lead to systems with an installation cost of only $3 per watt, producing electricity at a cost of 8-10 cents per kilowatt/hour, making solar electricity a more cost-competitive and integral part of our nations energy mix.

Re:Cost is the issue (2, Interesting)

glittalogik (837604) | more than 7 years ago | (#17126100)

They're only related if the more efficient panel isn't significantly more expensive to produce. That is, of course, largely a matter of demand; the more of something you want/make/buy/sell, the more refined the production process becomes and the cheaper the individual units become - in this case, solar panels and therefore kilowatt hours.

Frankly I'm in favour of biting the bullet and making this a personal routlay, and am looking forward to doing so when I have a property to do it to. If someone can afford to buy a house, they can afford to put some bloody photovoltaics on the roof and if that adds an extra 6 months to their mortgage then so be it. For once it'd be nice to see economics take a back seat to environmental responsibility.

Re:Cost is the issue (1)

simm1701 (835424) | more than 7 years ago | (#17126158)

The 2 are not necessarily related. Lets say I have a choice of 2 panels Panel A is 1sqm and is 80% effiecient due to some new process someone has come up with (this is hypothetical remember) but due to it using nano tech to make it it costs $10,000 to buy this panel and fit it Panel B on the other hand is fairly old technology, has 10% efficiency but costs $125 for a 1sqm panel inc fitting You would need 8 of panel B, costing $1000 to have the same wattage capacity of panel A, but panel A would cost 10 times more - so efficency does not necessary improve the wattage/cost ratio. The more efficient panels do have one major advantage though - they increase the maximum power generation capability for a given square area. And over time the cost of manufactoring the more efficient panels is likely to drop

Re:Cost is the issue (-1, Troll)

Anonymous Coward | more than 7 years ago | (#17125726)

Personally, I'd rather see a decrease in watt-joule per newton-meter, and an increase in cash flow into my pocket. Also, I'd like to eat more desserts and get laid.

Re:Cost is the issue (4, Insightful)

Rinikusu (28164) | more than 7 years ago | (#17125826)

Erm.. deserts are empty.. of what?

Lots of animals and wildlife flora/fauna live in the deserts. Many of which are endangered. Many of which provide valuable eco-service to the land around them. It might not be prudent to just blot out the sun with solar collectors and think everything's going to be okay.

I'd rather see these on rooftops, supplementing power sources in a more local fashion where their impact will be minimal.

Re:Cost is the issue (1)

Darkman, Walkin Dude (707389) | more than 7 years ago | (#17125930)

Lots of animals and wildlife flora/fauna live in the deserts. Many of which are endangered. Many of which provide valuable eco-service to the land around them. It might not be prudent to just blot out the sun with solar collectors and think everything's going to be okay.

Tens of thousands (or more) of human beings were killed very recently over another energy source, oil. What makes you think a few snakes and scorpions are going to stop them if this is viable? And if you want an eco-service, by shading a lot of desert you might well be able to turn it into valuable farmland or something like that.

I would be very interested to see what savings this could bring from a rooftop installation however, in a temperate climate.

Re:Cost is the issue (3, Insightful)

WindBourne (631190) | more than 7 years ago | (#17126036)

So now, you are suggesting that we should put all of America's power generation in exactly one small spot. Yes. Oh yes. I can hear it already:

there is our next target with the new bomb (thank you, george), the Americans make it sooooo easy.
.

In addition, as to farmland in the desert, well here is a couple of thoughts:
  • There is actually too much unproductive farmland in America. We have a lot of land that is actually very poor, but still in production due to farm subsidies. And desert land is very nutrient poor.
  • Here in the West, and more so the SouthWest, we have this issue with water. We are lacking. Plan on sending some our way? We could use it more for our pools and golf courses. And yes, the city folks, esp those from back east, will demand that the water go to them.
  • A simple fact is that plants need light. The solar cells use what? Why light. And they all have a back that reflects the unused photons back through the layer so that it might get another chance at being used.

Re:Cost is the issue (4, Insightful)

bogjobber (880402) | more than 7 years ago | (#17126124)

Looks like someone needs a refresher course in ecology. Deserts are very rich and diverse zones. Remember, a desert isn't just sand dunes. Just because it isn't green and not many people live there (the US West/Southwest) doesn't mean it's a barren wasteland. Also, the reason why the desert isn't farmland is because there is no water. The thing preventing Nevada from being a rich agricultural region is a rather large mountain range, not too much sun. Unless you can find a way of getting more water to the desert (like the Northwest) then it isn't going to produce squat.

Besides, other areas of the country still receive sunshine. I bet when you take into account the costs of maintaining the transmission infrastructure as well as the risks associated with a centralized power source most of the solar stations would be stationed near population centers instead of concentrated in one area.

Re:Cost is the issue (1)

Conanymous Award (597667) | more than 7 years ago | (#17125942)

How 'bout dem oceans instead of deserts? Floating Beowulf clusters of these (just had to say it that way) wouldn't harm the environment.

Re:Cost is the issue (1)

J.Y.Kelly (828209) | more than 7 years ago | (#17126154)

How 'bout dem oceans instead of deserts? Floating Beowulf clusters of these (just had to say it that way) wouldn't harm the environment.
You really wouldn't want to do that. Oceans are already hugely productive with respect to the light which falls on them. It might be a bad idea to shade the source of ~80% of net global oxygen production [wikipedia.org]!

Speaking of deserts having their role (1)

Moraelin (679338) | more than 7 years ago | (#17126134)

There was an article linked to from The Register (but I'm too lazy to search for it right now= where they figured out that tens of tons of earth dust from some hole in Sahara are carried by wind currents all the way over to the Amazon. They said that without that, the rain forest would be a lot less impressive.

Kinda makes one wonder. Take some of the massive solar energy input out (and/or add enough wind turbines around too, while we're at it) and those currents may no longer carry any dust over, or carry it just a few miles into the Atlantic. Well, that one is obvious, but it makes me wonder what else. The Gulf Stream is also powered by the sun, for example, and that's what makes the climate of, say, the Netherlands be not quite the same as that of Siberia.

Seriously (1)

syncrotic (828809) | more than 7 years ago | (#17126162)

Oh yes of course, the desert is a precious and fragile ecosystem that needs to be protected. It's not just a land of oppressive heat, sand, rock, and thorny vegation - it's home to some very rare species of, umm, cactii and scorpions, that represent, uh, valuable biodiversity that must be protected.

Nature must be sheltered from the influence of evil parasitic humans. It is to be protected for its own sake, and no other justification is necessary.

This kind of attitude has put a halt to multibillion dollar projects that would have benefitted thousands of people, and sometimes entire nations. If it were up to people like you, we'd all be freezing in the dark.

Re:Cost is the issue (1, Insightful)

DilbertLand (863654) | more than 7 years ago | (#17125842)

Everyone always seems to forget how much energy actually goes into producing a solar cell. It wasn't all that long ago that the electricity needed just to melt the silicon was more energy than the cell would generate throughout it's entire lifetime (they do degrade over time). That doesn't even include all the energy consumed during any additional manufacturing, transportation, and installation.

Re:Cost is the issue (2, Interesting)

mrbluze (1034940) | more than 7 years ago | (#17125986)

A viable business model for the solar energy solution might be for new houses to be built with high efficiency solar arrays on rooves, using the energy for household purposes and selling excess energy. Therefore a return on investment could be expected. Excess daytime energy can be stored for night-time use, though this is fairly inefficient (the most efficient method is pumping water uphill to a dam). In places like Australia this is quite achievable, as governments have been fairly forthcoming at times with giving grants and subsidies to people taking up environmental initiatives, and on the other hand issuing strict regulations for energy saving methods of house design. With the prices of electricity which exist in Australia, for example, it's actually a very achievable aim - with a $10,000AUD outlay for a regular household solar array, recouping the investment occurs in about 10 years. I don't think having solar farms is the only solution - only the big business solution.

Re:Cost is the issue (1)

gertvs (1033762) | more than 7 years ago | (#17126176)

Cost per watt is indeed important for widespread acceptance. But conventional energy prices *will* go up sooner or later, and the real bottom line will be what we are willing to, or can, pay for a watt. It is likely that the cost curves will converge and at some point in time cross. After that few will be interested in conventional energy. This solar energy efficiency milestone is important to guesstimate if and when this will happen.

A large solar collector would also.. (4, Interesting)

nullchar (446050) | more than 7 years ago | (#17125652)

A large solar collector would also shade the ground and absorb the heat (energy) that the surrounding ground and air would normally receive. I guess, taking extra heat (energy) from one place, and adding it to lots of others may not be bad...

What about the cost in sending that energy down the wire? Would it be best to build one big-ass solar array? Or would it be better to distribute smaller collectors over a large area, even if the sunlight is not optimal?

Re:A large solar collector would also.. (0)

Anonymous Coward | more than 7 years ago | (#17125690)

Um, I would guess a bunch of little ones. Because if we had one big one, a storm would kill all of our power temporarily.

Re:A large solar collector would also.. (0)

Anonymous Coward | more than 7 years ago | (#17125704)

A large solar collector would also shade the ground and absorb the heat (energy) that the surrounding ground and air would normally receive. I guess, taking extra heat (energy) from one place, and adding it to lots of others may not be bad...

I wonder what the environmental effect of dramatically cutting down the heat that hits the desert would have on not only the local environment/wildlife but on weather systems. This is much more than a butterfly flapping its wings...

Re:A large solar collector would also.. (1)

Jugalator (259273) | more than 7 years ago | (#17125736)

On the other hand, deserts are expanding very quickly today, and it's quite a difference in their sizes compared to e.g. the early 1900's now.

Re:A large solar collector would also.. (1)

poopdeville (841677) | more than 7 years ago | (#17125878)

I suppose it could be bad globally, but global weather effects would get lost in the inherent "randomness" of weather. The butterfly effect you alluded to shows that all events are (in a fairly abstract sense equally) weather changing, not just the big ones.

I'm thinking 260 or so square miles of solar cells would severely alter the local ecosystem. But who cares? There's a chance for more life in the area with lowered ground temperatures.

Re:A large solar collector would also.. (1)

MichaelSmith (789609) | more than 7 years ago | (#17125712)

A large solar collector would also shade the ground and absorb the heat (energy) that the surrounding ground and air would normally receive. I guess, taking extra heat (energy) from one place, and adding it to lots of others may not be bad...

PV cells have a lower albedo than the Earth as a whole, at least solid land, anyway. So over land they will result in more heat being transferred to the amosphere than the soil under them would have. Sea water has a pretty low albedo so I don't know if this applies over land as well.

No, not pale, pink-eyed mutants... (1, Informative)

Anonymous Coward | more than 7 years ago | (#17125860)

Hey MichaelSmith,

Here's the link [wikipedia.org] you forgot.

Re:A large solar collector would also.. (1)

AK Marc (707885) | more than 7 years ago | (#17125824)

Both. Build a big ass array in Arizona/Nevada to power the west coast. Then have smaller areas around the midwest and south for the rest. Also, having offshore platforms with panels on them to desalinate water and generate H2 would not be a bad idea.

How about... (1)

Belial6 (794905) | more than 7 years ago | (#17125900)

How about we put them some place that is already covered. You know like above houses. Kind of like... say... a roof. I don't know how many square miles of the US is rooftops, but I bet if you added it up, you wouldn't need much in the way of non-building covering space for whatever extra power was needed to power the US.

Finally! (0, Troll)

Threni (635302) | more than 7 years ago | (#17125666)

> At 40% efficiency, it looks like a square 265 miles on a side in the American southwest would do it.

A use for Israel! At last they can put something positive back into the world!

Re:Finally! (-1, Flamebait)

Anonymous Coward | more than 7 years ago | (#17125694)

This only gets modded -1, Flamebait because of the Elders of Zion.

Re:Finally! (1)

MichaelSmith (789609) | more than 7 years ago | (#17125724)

A use for Israel!

How about the empty quarter of Saudi Arabia?

For me, this represents an opportunity to generate the power where I will need it. Transmission systems will be less important in the future.

Re:Finally! (1)

xenocide2 (231786) | more than 7 years ago | (#17125854)

40 percent is impressive, but the cost is likely still damn high, and not an incredible improvement over the previous record. In short if solar wasn't close to making since yesterday, it still won't today. It might some time in the future, but probably not tomorrow.

Re:Finally! (1)

MichaelSmith (789609) | more than 7 years ago | (#17125950)

40 percent is impressive, but the cost is likely still damn high

If the cost is high because of complexity then large scale manufacturing should be able to bring the cost down. Think how cheap LSI chips are. Of course you need the demand to be high so that volumes can be increased so that prices can come down and stimulate demand for which you need...

Re:Finally! (1, Flamebait)

gunny01 (1022579) | more than 7 years ago | (#17126108)

That comment is so ignorant, I'm gonna included an equally bigoted comment of my own!

Why not use Lebanon? They don't have any oil and the knowledge of the falafel has been safely exported.

Not long (1, Redundant)

sc0p3 (972992) | more than 7 years ago | (#17125698)

Not long before solar cars and roof top solar panels =)

Re:Not long (0)

Anonymous Coward | more than 7 years ago | (#17125948)

1982 called, it wants its shit back.

Silly figure (0)

Anonymous Coward | more than 7 years ago | (#17125714)

At the population density of, say, Manhattan (or downtown Paris, Hong Kong, or Shanghai) you could fit most of the population of the Earth into a square 265 miles on a side. Such a figure doesn't really shed much light on the actual cost of switching to Solar Power. It doesn't even do a good job of helping us better understand how much land we would have to set aside for that sort of switch (in the same way as the 265 mi. x 265 mi. area containing the population of the Earth doesn't really shed much light on how much impact human habitation has on the Earth and how much land area is actually used). It's a ridiculous figure with very little utility.

Solar cells... (1)

Sneakernets (1026296) | more than 7 years ago | (#17125720)

This is Great news. I've seen Solar Cells evolve from yucky novelties (solar powered fan hats) to calculators that can operate on such little light energy. I thought that was efficient... now it's even better?

I want these on every roof in America.

265 miles on a side... (1)

Goldsmith (561202) | more than 7 years ago | (#17125738)

Gee, that's about the size of Utah [wikipedia.org].

Re:265 miles on a side... (0)

Anonymous Coward | more than 7 years ago | (#17126070)

That's not an accident. We finally found a use for it.

All we have to do now is pave over the Mormons.

The coming 'power centers' (1)

geosyncline (1036246) | more than 7 years ago | (#17125748)

Because transmitting electricity long distances is prohibative, why not setup 'energy creation' centers in the tropics, where a variety of transportable energy could be generated and then shipped/pipped to wherever it needs to go. You could go the hydrogen generation route with it's engineering difficulties that have yet to be overcome, or find another more easily transportable, but more energy soaking medium. Regardless, if 40% becomes reality... at the right cost naturally, then the next question is how do you get the energy from point A to point B? Seems to me you have to either bottle it up for transport or have a large breakthrough in supercondctivity. (even then the distances seem prohibative) If these things can be made cheaply and have a good life span on them, then even having them as supplemental power on the roof of your house could be a major win!

They already exists (1)

WindBourne (631190) | more than 7 years ago | (#17126058)

They are called Enron, Shell Oil, Xcell Energy, etc. They use centralized power plants and distribute power to other places. The real new approach will be moving back to a true distributed energy generation.

Re:They already exists (1)

cliffski (65094) | more than 7 years ago | (#17126146)

well said. There is a lot of talk in the UK (talk is all it is sadly) of 'turning each home into a micro-powerstation'. I love this idea. Why should I be paying so much cash to some big (often foreign-owned) evil megacorp for my power, when I could use my roofspace to generate a lot of it myself? Doing so take transmissions losses away altogether.
If it was a simple matter of attaching some panels and plugging a cable into a wallsocket, I'd be there already, but the installation of solar setups is a complex enough deal for now that I think I'll wait till I move hosue, and know I'll be there long enough to get my investment back.

They will never let it happen (1)

rssrss (686344) | more than 7 years ago | (#17125804)

"it looks like a square 265 miles on a side in the American southwest would do it."

Like 2/3rds of Arizona. Just wait until the eco-freaks figure out what covering that much desert would do the blind desert pup fish. There is no way they would let you cover 70,000 square miles of desert with mirrors.

Re:They will never let it happen (1)

WindBourne (631190) | more than 7 years ago | (#17125926)

And there is no need to do so. The simple answer is that these do not have to supply all of energy. In fact, it is best that it not do so. The reason why countries like America are in the trouble that they are in, is that we depend on limited types of energy generation; Coal and Oil. Even if we drop Oil and Coal today, it would be in our best interest to have multiple sources spread out all over the USA so that even if a nuke is blown up on it, it will not take out all generation.

But if we can get a great deal more wind, geo-thermal, solar, and even nukes combined with true energy storage, then we are in good shape.

No problem there. (1)

DimGeo (694000) | more than 7 years ago | (#17125972)

That's for the whole world, not just the USA. Put panels on each roof globally and you won't even notice (while gaining much more energy than needed).

where the facts? (5, Informative)

Anonymous Coward | more than 7 years ago | (#17125808)

So it's a bit unclear what the article means by 40% efficient as the article seems to confuse the concentrator part of the solar cell with the multi-junction part. The concentrator doesn't make the device more efficient at converting solar radiation into electrical power, it just concentrates the light so you don't have to use as large of a device. The idea being that the solar cell material is expensive but the optics are relatively cheap, so you might as well focus as much light on the device as it will absorb and still function.

The multi-junction part comes from the idea that you can, using a solar cell, only extract as much energy from a photon as the size of something called the band gap of the material that the cell is made from. At the same time, a solar cell can only absorb photons with energies higher than the band gap. If the bandgap is small, as it is in silicon, then you can absorb most of the suns rays, but you can only get about 1 electronVolt of energy out of each one no matter how much energy the photon has. Since the bulk of photons emitted by the sun have more than 1 electronVolt of energy Si solar cells waste alot of the energy in sunlight as heat. If you make the solar cell out of a semiconductor with a larger bandgap then you absorb fewer photons (more of the solar spectrum lies below the critical energy for absorption) but you extract more energy from each photon. So, for a solar cell made from one material there is a sweet spot in terms of the bandgap that maximizes the energy extracted. Multi-junction cells try to overcome this by combining multiple devices with different bandgaps so that you can maximize both the total number of photons converted to electricity and the energy extracted from each photon.

Re:where the facts? (2, Informative)

swebster (530246) | more than 7 years ago | (#17126062)

The concentrator doesn't make the device more efficient at converting solar radiation into electrical power, it just concentrates the light so you don't have to use as large of a device.
Actually, that's not quite right. Higher light intensity does make the cells more efficient. It's one of the advantages of using concentrator cells.

Downsides (2, Insightful)

ChowRiit (939581) | more than 7 years ago | (#17125814)

I'm all in favour of clean energy, I think it's a laudable goal, but we shouldn't be patting eachother on our backs just yet.

Firstly, these solar cells are no doubt incredibly expensive - any high efficiency ones are. Secondly, they're probably made using rare and/or exotic materiels, making manufacturing in bulk tricky, and thirdly there's likely to be a lot of pollution created in the manufacturing process for by-products et cetera (it's a problem with less efficient cells too, but the more efficient ones are generally more pollutions).

Lastly, there's another issue. What happens when the sun goes behind a cloud? You need to be able to cover the entire slack in an instant, because you NEED a constant power output. That means you NEED enough GAS powerplants to power the whole world too, as they're the only type of power plant you can literally turn the dial and turn up the output.

Me, I'm going to be sitting here hoping that the test fusion plant they're building in France works, because from what I've learnt lately, if it doesn't, we're screwed.

Re:Downsides (2, Insightful)

Atlantis-Rising (857278) | more than 7 years ago | (#17125914)

Er, ever heard of batteries? It's perfectly possible to have capacatance stations built into the grid that serve as temporary UPS units for when the power slacks. Similarly, if you spread the generating stations out roughly evenly around the planet and build in enough extra capacity, (maybe 5%, I'm talking out of my ass here) the chances of cloud covering enough of that generator grid to cause a severe power loss are probably negligable.

Presumably, you'd want the capacitance spread out across the grid- not only to prevent brownouts due to lack of power production, but also to temporarily handle spikes in load and to handle temporary grid failures. Neighbourhood or even house-scale capacitance units wouldn't require much storage and could effienctly handle temporary spikes in load, like the use of (for example) a microwave or vacuumn cleaner.

Of course, if you're splitting up capacitance that way, why not split up generation that way too? Just use the power grid as a way to ship excess power around to handle temporary generation losses.

Energy from the sun at maximum potential is what, 1 KW per square meter? My house's roof is probably 15-20 square meters; 12 KW on a sunny day is great. I have absolutely no idea at the moment how much power I'm actually using, on average, (including nights, etc) but I'll bet this won't be enough to cover it. That's okay. Even if it covers half of it...

Re:Downsides (1)

Odinson (4523) | more than 7 years ago | (#17126114)

It's enough to cover my electrical needs. At 350 kwh a month in a 2 bedroom apt in queens with two adults and a baby living in it. That's with near full time use of two window air conditioners in the summer, and part time use of a dishwasher and a couple of nasty CRTs. All in an ancient, very inefficent building.

Of course there still is the issue of heat 8 months a year since those would be the less sunny days.

And That... (3, Interesting)

Belial6 (794905) | more than 7 years ago | (#17125924)

"Lastly, there's another issue. What happens when the sun goes behind a cloud? You need to be able to cover the entire slack in an instant, because you NEED a constant power output. That means you NEED enough GAS powerplants to power the whole world too, as they're the only type of power plant you can literally turn the dial and turn up the output."

And that is what fuel cells are really for. Forget having hydrogen delivered to your home so that you can use a fuel cell as a generator. No, you use photovolic at the home to generate a tank of Hydrogen so that you can convert it back to electricity when you need it. The real promise of fuel cells is for use as a very clean battery.

Re:Downsides (5, Interesting)

hcdejong (561314) | more than 7 years ago | (#17125966)

That means you NEED enough GAS powerplants to power the whole world too, as they're the only type of power plant you can literally turn the dial and turn up the output.

No, they're not. Hydro plants can do this as well. The UK uses several hydro plants like Dinorwig [fhc.co.uk] to cover peak loads. Dinorwig can go from 0 to 1320 MW in 12 seconds, and has a peak output of about 1800 MW. It is built as an accumulator system, pumping water up the mountain at night (using excess capacity from nuclear and fossil fuel plants) so it doesn't depend on a huge water supply (river). Efficiency (W generated vs. W needed to pump the water up the mountain) is about 70%.

Re:Downsides (1)

SpaghettiPattern (609814) | more than 7 years ago | (#17126132)

What happens when the sun goes behind a cloud?

Worse still, what happens when the sun hides behind the earth where he can't be seen? (I know the bugger, he's a bastard and does so regularly.)

We need site redundancy. One plant in the US, one in Russia and one in the Sahara.

Don't worry, we'll get the sun of a bitch 24/7.

Panels On The Roof (3, Interesting)

DaftShadow (548731) | more than 7 years ago | (#17125844)

I've been recently wrestling with the idea of putting solar panels up myself, but the truth of the matter is that I cannot afford the current RoR's length of time (approx 13-18years), nor can I get enough panels onto the limited rooftop I plan to use to cause a very big dent. A huge increase in efficiency of space, as well as cost/watt, changes these numbers *dramatically.* This is awesome.

- DaftShadow

Re:Panels On The Roof (5, Informative)

Nasarius (593729) | more than 7 years ago | (#17126032)

Contact your local power company. Many (such as LIPA) will pay for a large percentage of your costs.

Roofs of the future should be solar! (1)

arcite (661011) | more than 7 years ago | (#17126144)

Just imagine if every second house has solar power, even if it was just used to heat hot water, the energy savings would be enormous.

Still does not solve much (3, Insightful)

WindBourne (631190) | more than 7 years ago | (#17125864)

The issue is not one of generation. There is actually plenty of energy production (and more is coming on line with new wind and geo-thermal). Our problem is one of energy production when it is needed. Since solar (and most alternatives) will NEVER be able to produce 24x7 or even 8x7, then you need a way to save the energy. As it is, USA feds has been trying to force more research down the path of hydrogen. But the earliest will be around 2025 ,and that depends on having some MAJOR advancements in cost economics that make this solar cell efficiency games look like child's play. IOW, this route will not be happening.

Do not get me wrong. These solar cells are most likely a good thing. Of course, it depends on how the true cost relative to other methods. But this country needs to quit subsidizing oil and coal as well as have a multi-prong research in energy storage to really make the alternatives happen.

Re:Still does not solve much (3, Insightful)

magman (1036252) | more than 7 years ago | (#17125956)

You've got it completely wrong... One of the main benefits of the solar production is that it's distributed and produces during peak hours. In other words, the power is generated when it's needed and you don't have to transport it to the areas where it's being used. Think air conditioning In Japan it's already cost effective to install solar panels without subsidies, in other parts of the world you generally need subsidies to get it working economically. But this business is growing at a rate of 40% each year worldwide, it's only a matter of time!

Re:Still does not solve much (1)

WindBourne (631190) | more than 7 years ago | (#17126104)

Look, here southwest Co, we have 220 days of at least SOME sun. And further southwest, it is something like 230-265 days. These are not work days only. That means that 1/3 of them are sunless i.e. blocked from good light. So now, you need to have some other means of filling in the energy. That is why Xcell and others do not want wind. They do not serve when Xcell needs them. So Xcell creates coal plants that work as base system, and use natural gas for peak productions. But if we had good electrical storage, then we could get rid of the peak producers and slowly take out the base units as well. The storage would be filled by the alternative generators. As it is, Xcell gets huge fines when the lines come down in the summer due to heavy A.C. loads. And many times, those A.Cs. operate when the sun is not there.

Obligatory suburban subdivision response... (1)

Zhe Mappel (607548) | more than 7 years ago | (#17125872)

"At 40% efficiency, it looks like a square 265 miles on a side in the American southwest would do it."

NIMBY!

Re:Obligatory suburban subdivision response... (1)

ydra2 (821713) | more than 7 years ago | (#17126010)

Let me guess. You are from Texas. Well Texas is bigger than all the rest of the world put together aint it? 265 miles by 265 would fit right nicely in Texas and Texas gets lots of sunlight. So how about it Texans? Y'all wanna move out so we can build the biggest goddam solar plant this planet's ever seen? It'd be one mighty feather in your 10,000 gallon hat. And, owning all the worlds energy supply you could say "Don't mess with Texas" and we wouldn't.

Re:Obligatory suburban subdivision response... (1)

foo12 (585116) | more than 7 years ago | (#17126094)

Fine. Not In [Your] Back Yard. But how about on your roof? It's unused space and the energy benefits would be twfold (electricity generation and reduced cooling demands)

God, geeks are so incredibly stupid (5, Insightful)

Anonymous Coward | more than 7 years ago | (#17125910)

1. Deserts are not empty. They have an ecosystem.

2. There is no reason at all to fill a desert with solar cells, and then transport the energy across to the other side of the planet. Solar cells are installed locally, like on your roof, or in your back yard, on every roof across the planet. Most of the electricity consumed would be as Direct Current right from your rooftop, with an inverter converting for those appliances you still insist on retaining that us AC.

3. For dense city sitatuions with high rises who's energy needs can not be met by rooftops, etc., electricity can be sent via conventional AC lines across the conventional power grid from say no more than 50 miles away. Not the other side of the world.

4. Those who produce an excess of electricity beyond their need, sell it into the grid.

life span (1)

YeeHaW_Jelte (451855) | more than 7 years ago | (#17125968)

Solar cells cost a lot of energy to make, so what's the life span on these things? What's left if you subtract the manufactoring costs from the life-time energy generation of these things?

Here's an Idea (1)

pogopark (1004095) | more than 7 years ago | (#17126028)

I'm not sure if this would work at 40% -- might realistically need to be a bit higher -- but anyway, here's a thought. Energy can be transmitted in the form of microwaves, right? How about we build a ring or spherical grid of energy-collecting satellites around the Earth? They'd be interconnected with each other as well as with the ground... no matter where the Sun was beaming, there'd be enough energy to power the grid. High-frequency radiation is love, /.

Re:Here's an Idea (1)

Somatic (888514) | more than 7 years ago | (#17126052)

I'm not sure if this would work at 40% -- might realistically need to be a bit higher -- but anyway, here's a thought. Energy can be transmitted in the form of microwaves, right?

Fool! Didn't you ever play Sim City?

Re:Here's an Idea (1)

WindBourne (631190) | more than 7 years ago | (#17126122)

Microwaves. Cool idea. Prior to submitting for a patent, please study how your food is heated in your microwave oven. Hint; most of it is interaction between the wave and one type of molecule.

Re:Here's an Idea (1)

Timberwolf0122 (872207) | more than 7 years ago | (#17126142)

It's a nice idea, although some serious safety gear would be needed to ensure that the satelite does not inadvertantly beam a 20MW microwave on someones cat.

Is this efficiency measured at the earth's surface (1)

F00F (252082) | more than 7 years ago | (#17126138)

For some reason I'd thought that these highly-efficient multi-junction cells made by Spectrolab generally quote peak efficiency statistics as based on the ideal spectrum of incident solar light found in space, i.e. the orbits of the (usually geostationary) communications satellites where these cells are often encountered (hence why Boeing has the interest in Spectrolab). I thought I remembered that when you aactually account for the spectrum of visible light that makes it through the atmosphere, the efficiency goes down quite a bit.

But TFA hints at terrestrial applications, so maybe I'm just pulling this out of thin air, so to speak...

Anybody?
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