Breakthrough could double solar energy output | Hacker News Reader

Breakthrough could double solar energy output

latimes.com

49 pointspwg22 comments

This is not a new invention - it's called a multi junction solar cell. (Although this may be a cheap way to do - that part may be new.)

A photon needs to be above a critical energy to generate an electron - any energy above that is lost as heat. Any photons lower than that energy are unusable and also lost as heat.

A multi junction solar cell has multiple layers, each one capable of handling a different energy level.

For extra credit have the photon create an electron, then get emitted again with a lower energy only to be captured a second time by a lower layer.

But these type of solar cells cost a lot to make, so are mainly lab curiosities and are not used commercially much except in very specially applications where the cost is worth it.

> This is not a new invention - it's called a multi junction solar cell.

The photon absorption mechanism of multi-junction solar cells is still energy-transfer via electron-hole pair production.

This paper is utilizing excitons for the energy transfer, which truly is a different beast.

[One liner description of excitons: It is a positive and negative charge bound together by electrostatic attraction. It acts a lot like hydrogen with a hole taking the role of the proton.] (OK, that was two lines.)

Original article in Science Daily is here; http://www.sciencedaily.com/releases/2011/12/111215141617.ht...

Original paper is here; http://www.sciencemag.org/content/334/6062/1541

Everyone do yourselves a favor and read these instead.

I'll believe it when the headline reads "Breakthrough doubles solar energy..." not "could".

If I read the article correctly it seems that his improvement in experimental conditions is about 42% which is still very impressive.

"loads more electrical power"? "it's way cheap"? This sounds like it was written for a college newspaper by a freshman.

I also liked "much of the energy delivered by sunlight comes in the form of “hot” electrons"

I think the biggest statement in the article is The bottom line? Commonly used studies have listed dollars-per-watt of electricity as high as $7.61. According to Dr. Pearce, the real cost in 2011 is under $1 per watt.

That used to be the figure at which it would become feasible to convert to mass generation through solar... Maybe the timing is off, it came quicker than a lot of people expected, or else there are other factors still to be solved (availability?)

Should be an interesting space to watch over the next 2-5 years, now that we've reached the $1/watt mark...

This is indeed another confirmation of what I've heard earlier this year that 1kw can now be build for about $1000 (including inverters / control devices) -

now put this knowledge into context -

One of the biggest solar plants currently being planned / projected / soon to be build is in Greece with about 20km2 of area donated by the Greek state to build solar plant(s) up to 10+ GW (the numbers are only a few months old so not much change in efficiency here).

This should finally also make it clear to everyone what really is wrong with renewables & the "energy industry" today.

Simple arithmetic shows you that the consortium of the usual suspects (large energy conglomerates, quangos / PPPs, banks & private equity) is cutting themselves a premium of at least 100% for financing etc. And that does not include the frontloading of other cost, tax free revenues etc.

At the same time smaller decentralized plants are being hindered with changes in legislation, feed-in tariffs, planning permissions and ridiculously high building cost. At least here in Europe.

I would be very concerned if the solar energy output doubled. I don't have nearly enough insulation in my house, and I'm rather fond of the oceans.

Like all other "breakthroughs": it sounds great but I'll only get excited when/if it's actually been commercialized and available for purchase.

This is a very good point.

There are lots of "breakthroughs" which are genuinely incredibly useful, but not commercially viable (yet, or ever).

Until these things are viable commercially it is best not to get too giddy when hearing about them.

If only they defined what they meant by 'output' in the title to make it less sensational.

Most readers will likely interpret this as energy, which is not the case. The author meant output of electrons per photon absorbed. (The breakthrough is that high energy photons can be absorbed with less loss of energy by converting them into multiple electrons.)

Heh, another thing that the mass media tries to get me excited with, and just baits and switches with more of that good ole coal and oil.

Who cares if they discovered it if I can never buy it.

according to a rerun of the a speech by the australian climate change commissioner to the national press club i watched a bit of yesterday, depending on where you live the current cost curve of solar energy will place on par with brown coal in 2018.

technological development will only accelerate change.

think it was this speech http://www.npc.org.au/speakerarchive/tim-flannery.html... old media == no stream or even a transcript :\

Might be this one, no transcript though: http://www.abc.net.au/tv/bigideas/stories/2011/02/08/3131960...

Firstly, why would you assume you would never be able to buy it?

Secondly, it might not be directly relevant to people like you and I initially. If instead something like this could be cheap enough to bring to the massive billion(s) of people with no power or light at night -- that's huge. Once it's ready, and I'm nearly sure it eventually will be (solar in general), then it'll be ready for us to consume.

They described the plastic as 'organic', hopefully this means it comes from somewhere other than from petroleum - does anyone know enough to comment?

If it means organic as in 'carbon-based compound' then it's just redundant.

By "organic" they most likely mean carbon based, which leads me to believe that it is most likely petroleum based.

Pentacene is synthesized from benzene, and the primary source for benzene is currently petroleum. It doesn't have to be, but benzene has always been a relatively cheap "garbage" byproduct of other products (first coke, then petroleum fuels). It is unlikely that over the long term extraction of fossil fuels would be a cost-efficient means of deriving chemicals that are now heavily subsidized by the primary products; bacterial synthesis would probably much more practical. That is to say one shouldn't dismiss non-fuel petrochemicals simply because the current cheapest source is petroleum -- it won't always be unless the demand for petrochemical fuels (or coal/coke) remains high. Ironically, then, things that are now petrochemicals could spell the end of the petrochemical industry if they contribute to a reduction in demand for fuel.

The author likely translated organic polymer to organic plastic, because they didn't realize that these words have very precise meanings and they thought that the word polymer would be 'scary'.

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