World record solar cell with 44.7% efficiency • Hacker News Board

Re: World record solar cell with 44.7% efficiency

#41

Post by jacquesm » Wed, Sep 25, 2013, 5:15 AM UTC

dgreensp wrote: post #39

So when does solar power become cheap and efficient enough that it's a real game changer? It seems like the numbers have gotten a lot better in recent years, at least in terms of efficiency.

Price per Watt of installed PV is what drives adoption so with efficiency as one term in there (Wattage output is a direct result of efficiency) the remaining ones (lifespan, efficiency over lifespan and production costs / unit area of panel) are still problematic enough to slow down wholesale adoption. To some extent this is right now offset by subsidies, you'll know that it has arrived when the subsidies are stopped and adoption still increases.

Re: World record solar cell with 44.7% efficiency

#42

Post by danielharan » Wed, Sep 25, 2013, 5:21 AM UTC

dgreensp wrote: post #39

So when does solar power become cheap and efficient enough that it's a real game changer? It seems like the numbers have gotten a lot better in recent years, at least in terms of efficiency.

We're at a tipping point already. What's helped the most recently is financing.

Solar is already cheaper than retail in a few states; see e.g. this map that lets you play with dates and scenarios: http://ilsr.org/projects/solarparitymap/

As for game changers, see e.g. http://www.greentechmedia.com/articles/read/are-utilities-re... http://grist.org/climate-energy/solar-panels-could-destroy-u...

Re: World record solar cell with 44.7% efficiency

#43

Post by officialjunk » Wed, Sep 25, 2013, 5:27 AM UTC

Now combine this with IBM's research to collect most of the energy lost to heat production and push the efficiency up to 80% http://arstechnica.com/science/2013/04/ibms-solar-tech-is-80...

Re: World record solar cell with 44.7% efficiency

#44

Post by baq » Wed, Sep 25, 2013, 5:31 AM UTC

idProQuo wrote: post #38

SamuelKillin wrote: post #35

Good on them. In reality, however, fuel from the sun is free and we have unlimited land. Getting the cost down and economies of scale are what everyone is really focussed on.

We have unlimited land, but I don't think we have unlimited Silicon with which to cover it.

sahara has all the land and all the silicon you may need.

Re: World record solar cell with 44.7% efficiency

#45

Post by ars » Wed, Sep 25, 2013, 5:34 AM UTC

brownBananas wrote: post #6

Is the composition of this one solar cell from 4 subcells of any significance? Is it just 4 for a reason?

The way a solar cell works is it absorbs only at one single frequency.

Photons below that frequency are lost and not used at all. If the photon is above the frequency then the energy up to that cutoff is used and the rest is wasted (either emitted as a new photon or as heat).

Meaning if you set the target frequency at infrared then you loose all the additional energy UV has over infrared.

By making multiple layers (junctions) you waste less energy, the more the better (in theory anyway).

Re: World record solar cell with 44.7% efficiency

#46

Post by ars » Wed, Sep 25, 2013, 5:35 AM UTC

bsullivan01 wrote: post #37

gilgoomesh wrote: post #15

Earlier quoted context omitted.

It's worse than that. There's no room for a single doubling of 44% efficiency. The theoretical maximum for multi-junction concentrator cells is about 86%: https://en.wikipedia.org/wiki/Shockley–Queisser_limit For single junction cells it's a mere 33%.

Interesting. Considering that solar is essentially "free" after you buy the equipment, something like Moore's Law can be applied to the price of solar panels or their longevity. We got plenty of space in our roofs :-)

Less space means less installation costs, and it means less raw materials.

Silicon is OK, but some of the other stuff doesn't exist on earth in sufficient quantity to use solar energy in quantity.

Re: World record solar cell with 44.7% efficiency

#47

Post by ck2 » Wed, Sep 25, 2013, 6:00 AM UTC

While nearly 45% is impressive, I'd rather see "cheap as paint" solar cells at 10% efficiency that are football fields in size.

Put them on every commercial rooftop and all that free space we have out west in the USA.

Re: World record solar cell with 44.7% efficiency

#48

Post by fauigerzigerk » Wed, Sep 25, 2013, 6:04 AM UTC

paul_f wrote: post #22

twelvechairs wrote: post #17

this is great but its worth noting that efficiency isn't really what's holding solar production back, its price. few peoples roofs are crammed with PV to the point where they can't fit more in.

This is the fundamental problem with PV. Compared to cheap natural gas, there just isn't much future in it

I don't understand what you see as a fundamental problem with PV. Prices for panels are dropping like a stone and efficiency is increasing. What's the fundamental problem?

Re: World record solar cell with 44.7% efficiency

#49

Post by tsotha » Wed, Sep 25, 2013, 6:07 AM UTC

jussij wrote: post #26

paul_f wrote: post #22

Earlier quoted context omitted.

This is the fundamental problem with PV. Compared to cheap natural gas, there just isn't much future in it

No Future? That might be true, except for that rather large elephant in the room call human-induced climate change.

Pretty sure that was sarcasm.

Re: World record solar cell with 44.7% efficiency

#50

Post by tsotha » Wed, Sep 25, 2013, 6:12 AM UTC

dgreensp wrote: post #39

So when does solar power become cheap and efficient enough that it's a real game changer? It seems like the numbers have gotten a lot better in recent years, at least in terms of efficiency.

Solar is already cheaper in most places provided you have net metering, which is a subsidy. But there's a limit to how many people can use the grid for free.