Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

World record solar cell with 44.7% efficiency

phys.org

Post reply on HN
Print view View original

101–110 of 127 posts

Re: World record solar cell with 44.7% efficiency

#101

Post by MikeCapone »

jnw2 wrote: post #36
MikeCapone wrote: post #21

Earlier quoted context omitted.

Efficiency matters, but price/watt matters more and there's still room for a kind of moore's law there.

Which of efficiency or price/watt matters more depends on the application. For example, I believe something like 4 m^2, 40% efficient, 8 hours of charging is enough to get electricity to drive a Tesla something like 30-40 miles. (In practice, I assume you'd cover all of the outside of the car with 40% efficient solar panels to make this work (or maybe even 80% if you can figure out how to build them), and then 4 m^2…

Absolutely. I should have been more precise.

I think that for maximizing the amount of electricity generated via solar power, price/watt matters most.

Re: World record solar cell with 44.7% efficiency

#102

Post by michaelwww »

mentos wrote: post #93
dredmorbius wrote: post #73

For those wondering about the significance of this announcement: As several people have noted, what matters for solar PV isn't efficiency but cost per Watt . The maximum available energy is 1W/meter^2 at ground. Single-layer PV efficiency is on the order of about 40%. Mutliple-layer cells can reach a maximum of around 80%. Even with existing efficiencies, the land space necessary to dedicate to solar power for all el…

Is long term storage necessary? Couldn't a coal powered plant be fitted with solar to create a hybrid solution where coal burning kicks in when the clouds come out? edit: The idea being that you can piggy back on the infrastructure already in place at power plants?

My initial reaction was that you can't turn coal plants on and off that way, which turned out to be correct:

http://www.ipautah.com/data/upfiles/newsletters/CyclingArtic...

Re: World record solar cell with 44.7% efficiency

#103

Post by kken »

dredmorbius wrote: post #73

For those wondering about the significance of this announcement: As several people have noted, what matters for solar PV isn't efficiency but cost per Watt . The maximum available energy is 1W/meter^2 at ground. Single-layer PV efficiency is on the order of about 40%. Mutliple-layer cells can reach a maximum of around 80%. Even with existing efficiencies, the land space necessary to dedicate to solar power for all el…

Solar power has something that has been proven to be an universial law for all manufacturing: The manufacturing cost decreases is a power function of cumulative production, also known as wright's law.

This is a very interesting paper about this concept: http://arxiv.org/abs/1207.1463

Moore's law is special because it relies on physical scaling (See Dennard Scaling) of the product. The transistors get smaller with each technology iteration, resulting in a physical correspondence to the economical law. Something like this does not exist for solar cells and most other products.

Re: World record solar cell with 44.7% efficiency

#105

Post by moocowduckquack »

JoeAltmaier wrote: post #95
moocowduckquack wrote: post #85

Earlier quoted context omitted.

So this new cell is 23% efficient, versus 46% if deployed orbitally That isn't how you calculate conversion efficiency. If there is no input to convert, you don't count that as a conversion loss.

Exactly. So lets talk about a different, important number. Watts per dollar per day. The only one your accountant/investor cares about. Its something like double or triple for space-based solar cells, if you can deploy them efficiently.

a. they have to be in space so your capital outlay is insane

b. you have massive efficiency losses in wireless power transmission

Re: World record solar cell with 44.7% efficiency

#106

Post by cauthonLuck »

marcfawzi wrote: post #18

When will the world run out of the "III-V semiconductor materials" ? And which nation or corporation currently controls the largest deposits?

That is the question. All of the materials are expensive themselves (gallium, indium) or expensive to process ( silicon) - which means these cells will never scale and replace oil.

Which is why dye-sensitized solar cells are such a promising alternative, despite their lower single module efficiencies of ~15% (20-30% for the expensive semiconductors discussed in OP). http://en.wikipedia.org/wiki/Dye-sensitized_solar_cell

Re: World record solar cell with 44.7% efficiency

#108

Post by X4 »

dredmorbius wrote: post #73

For those wondering about the significance of this announcement: As several people have noted, what matters for solar PV isn't efficiency but cost per Watt . The maximum available energy is 1W/meter^2 at ground. Single-layer PV efficiency is on the order of about 40%. Mutliple-layer cells can reach a maximum of around 80%. Even with existing efficiencies, the land space necessary to dedicate to solar power for all el…

Bill Gates invested in at least 5 Battery Startups who could revolutionize the capacity problems of the large power-grids worldwide: http://gigaom.com/2013/04/02/bill-gates-investors-back-sodiu... Soon replaced by graphene super capacitors..

How conservative do you sound when you promote Thorium reactors in a solar cell thread? ..some people have heard enough "positive" things about nuclear power now. There are cheaper, more reliable, regrowing and more efficient technologies that Nuclear power fans simply ignore. Nobody said that the power generated by nuclear fusion is lower than with green power, but definitely at scale.

Re: World record solar cell with 44.7% efficiency

#109

Post by dredmorbius »

forgottenpaswrd wrote: post #78
dredmorbius wrote: post #73

For those wondering about the significance of this announcement: As several people have noted, what matters for solar PV isn't efficiency but cost per Watt . The maximum available energy is 1W/meter^2 at ground. Single-layer PV efficiency is on the order of about 40%. Mutliple-layer cells can reach a maximum of around 80%. Even with existing efficiencies, the land space necessary to dedicate to solar power for all el…

"The maximum available energy is 1W/meter^2 at ground" Where are you from, Britain? http://en.wikipedia.org/wiki/Sunlight ""sunshine duration" to mean the cumulative time during which an area receives direct irradiance from the Sun of at least 120 watts per meter" "The total amount of energy received at ground level from the sun at the zenith is 1004 watts per square meter" This depends on altitude of course, the max…

Where are you from, Britain?

Doh! 1kW/meter^2. Apologies.

More closer to the equator, less in higher lattitudes and/or where topography (valleys, canyons) or weather (fog, clouds) interfere, though even diffuse sunlight can provide significant power.

Re: World record solar cell with 44.7% efficiency

#110

Post by dredmorbius »

anovikov wrote: post #74
dredmorbius wrote: post #73

For those wondering about the significance of this announcement: As several people have noted, what matters for solar PV isn't efficiency but cost per Watt . The maximum available energy is 1W/meter^2 at ground. Single-layer PV efficiency is on the order of about 40%. Mutliple-layer cells can reach a maximum of around 80%. Even with existing efficiencies, the land space necessary to dedicate to solar power for all el…

Not true at all. Your statement about available land is correct of course, but the important part of picture is that the soft costs for construction of solar electric power plants are already much higher than hard costs. And, improving efficiency is a great way to cut them. Imagine a 10 MW power plant built out of panels with 10% efficiency. If you replace them with 20% efficient panels, you increase output 2x withou…

Sure, you can increase your efficiency, but:

There's a hard upper limit. 1 kW/meter^2 (mis-typed as 1W above). And you've got diminishing marginal returns of more efficient cells. The truth is that the land requirements are likely to go down by a factor of 2-4 maximum. Other cost factors (transmission, but especially storage) will dwarf these.

Once you've provisioned land for solar, the key costs are in replacing the panels every 20-40 years or so. Wind, stones, hail, and simple degredation will mandate this. Physical support infrastructure is likely more robust.

Land use for solar isn't dedicated-purpose for most applications. Even solar thermal can be used for grazing or other uses. PV can simply go on top of existing structures. You're not talking land acquisition so much as site acquisition.

Solar and wind are likely to be overprovisioned where possible. In the sense that you'll provide more capacity than is strictly needed to meet electrical demand. In part because you're not going to get 100% duty cycles ("capacity factor", which is how power installations are rated, are typically ~20 - 40%), and because you don't have an accelerator pedal, only a brake. Solar and wind aren't dispatchable, only sheddable. With overcapacity you've got the option of converting "excess" into other usable and storable forms of energy (hydrogen, methane, battery storage, electricity-to-fuels, etc.), or for intermittent but high-energy needs.

We've got cost reductions built in to PV production for the foreseable future. Again, efficiency improvements need to be considered in terms of total cost per Watt / kWh delivered*.

Post reply on HN